Econstudentlog

Astrophysics

Here’s what I wrote about the book on goodreads:

“I think the author was trying to do too much with this book. He covers a very large number of topics, but unfortunately the book is not easy to read because he covers in a few pages topics which other authors write entire books about. If he’d covered fewer topics in greater detail I think the end result would have been better. Despite having watched a large number of lectures on related topics and read academic texts about some of the topics covered in the book, I found the book far from easy to read, certainly compared to other physics books in this series (the books about nuclear physics and particle physics are both significantly easier to read, in my opinion). The author sometimes seemed to me to have difficulties understanding how large the potential knowledge gap between him and the reader of the book might be.

Worth reading if you know some stuff already and you’re willing to put in a bit of work, but don’t expect too much from the coverage.”

I gave the book two stars on goodreads.

I decided early on while reading the book that the only way I was going to cover this book at all here would be by posting a link-heavy post. I have added some quotes as well, but most of what’s going on in this book I’ll only cover by adding some relevant links to wiki articles dealing with these topics – as the link collection below should illustrate, although the subtitle of the book is ‘A Very Short Introduction’ it actually covers a great deal of ground (…too much ground, that’s part of the problem, as indicated above…). There are a lot of links because it’s just that kind of book.

First, a few quotes from the book:

“In thinking about the structure of an accretion disc it is helpful to imagine that it comprises a large number of solid rings, each of which spins as if each of its particles were in orbit around the central mass […] The speed of a circular orbit of radius r around a compact mass such as the Sun or a black hole is proportional to 1/r, so the speed increases inwards. It follows that there is shear within an accretion disc: each rotating ring slides past the ring just outside it, and, in the presence of any friction or viscosity within the fluid, each ring twists or torques the ring just outside it in the direction of rotation, trying to get it to rotate faster.

Torque is to angular momentum what force is to linear momentum: the quantity that sets its rate of change. Just as Newton’s laws yield that force is equal to rate of change of momentum, the rate of change of a body’s angular momentum is equal to the torque on the body. Hence the existence of the torque from smaller rings to bigger rings implies an outward transport of angular momentum through the accretion disc. When the disc is in a steady state this outward transport of angular momentum by viscosity is balanced by an inward transport of angular momentum by gas as it spirals inwards through the disc, carrying its angular momentum with it.”

“The differential equations that govern the motion of the planets are easily written down, and astronomical observations furnish the initial conditions to great precision. But with this precision we can predict the configuration of the planets only up to ∼ 40 Myr into the future — if the initial conditions are varied within the observational uncertainties, the predictions for 50 or 60 Myr later differ quite significantly. If you want to obtain predictions for 60 Myr that are comparable in precision to those we have for 40 Myr in the future, you require initial conditions that are 100 times more precise: for example, you require the current positions of the planets to within an error of 15m. If you want comparable predictions 60.15Myr in the future, you have to know the current positions to within 15mm.”

“An important feature of the solutions to the differential equations of the solar system is that after some variable, say the eccentricity of Mercury’s orbit, has fluctuated in a narrow range for millions of years, it will suddenly shift to a completely different range. This behaviour reflects the importance of resonances for the dynamics of the system: at some moment a resonant condition becomes satisfied and the flow of energy within the system changes because a small disturbance can accumulate over thousands or millions of cycles into a large effect. If we start the integrations from a configuration that differs ever so little from the previous configuration, the resonant condition will fail to be satisfied, or be satisfied much earlier or later, and the solutions will look quite different.”

“In Chapter 4 we saw that the physics of accretion discs around stars and black holes is all about the outward transport of angular momentum, and that moving angular momentum outwards heats a disc. Outward transport of angular momentum is similarly important for galactic discs. […] in a gaseous accretion disc angular momentum is primarily transported by the magnetic field. In a stellar disc, this job has to be done by the gravitational field because stars only interact gravitationally. Spiral structure provides the gravitational field needed to transport angular momentum outwards.

In addition to carrying angular momentum out through the stellar disc, spiral arms regularly shock interstellar gas, causing it to become denser, and a fraction of it to collapse into new stars. For this reason, spiral structure is most easily traced in the distribution of young stars, especially massive, luminous stars, because all massive stars are young. […] Spiral arms are waves of enhanced star density that propagate through a stellar disc rather as sound waves propagate through air. Like sound waves they carry energy, and this energy is eventually converted from the ordered form it takes in the wave to the kinetic energy of randomly moving stars. That is, spiral arms heat the stellar disc.”

“[I]f you take any reasonably representative group of galaxies, from the group’s luminosity, you can deduce the quantity of ordinary matter it should contain. This quantity proves to be roughly ten times the amount of ordinary matter that’s in the galaxies. So most ordinary matter must lie between the galaxies rather than within them.”

“The nature of a galaxy is largely determined by three numbers: its luminosity, its bulge-to-disc ratio, and the ratio of its mass of cold gas to the mass in stars. Since stars form from cold gas, this last ratio determines how youthful the galaxy’s stellar population is.

A youthful stellar population contains massive stars, which are short-lived, luminous, and blue […] An old stellar population contains only low-mass, faint, and red stars. Moreover, the spatial distribution of young stars can be very lumpy because the stars have not had time to be spread around the system […] a galaxy with a young stellar population looks very different from one with an old population: it is more lumpy/streaky, bluer, and has a higher luminosity than a galaxy of similar stellar mass with an old stellar population.”

Links:

Accretion disk.
Supermassive black hole.
Quasar.
Magnetorotational instability.
Astrophysical jet.
Herbig–Haro object.
SS 433.
Cygnus A.
Collimated light.
Light curve.
Lyman-alpha line.
Balmer series.
Star formation.
Stellar evolution.
Black-body radiation.
Helium flash.
White dwarf (featured article).
Planetary nebula.
Photosphere.
Corona.
Solar transition region.
Photodissociation.
Carbon detonation.
X-ray binary.
Inverse Compton scattering.
Microquasar.
Quasi-periodic oscillation.
Urbain Le Verrier.
Perturbation theory.
Elliptic orbit.
Precession.
Axial precession.
Libration.
Orbital resonance.
Jupiter trojan (featured article).
Late Heavy Bombardment.
Exoplanet.
Lorentz factor.
Radio galaxy.
Gamma-ray burst (featured article).
Cosmic ray.
Hulse–Taylor binary.
Special relativity.
Lorentz covariance.
Lorentz transformation.
Muon.
Relativistic Doppler effect.
Superluminal motion.
Fermi acceleration.
Shock waves in astrophysics.
Ram pressure.
Synchrotron radiation.
General relativity (featured article).
Gravitational redshift.
Gravitational lens.
Fermat’s principle.
SBS 0957+561.
Strong gravitational lensing/Weak gravitational lensing.
Gravitational microlensing.
Shapiro delay.
Gravitational wave.
Dark matter.
Dwarf spheroidal galaxy.
Luminosity function.
Lenticular galaxy.
Spiral galaxy.
Disc galaxy.
Elliptical galaxy.
Stellar dynamics.
Constant of motion.
Bulge (astronomy).
Interacting galaxy.
Coma cluster.
Galaxy cluster.
Anemic galaxy.
Decoupling (cosmology).

June 20, 2017 Posted by | Astronomy, Books, Physics | Leave a comment

Cosmology: Recent Results and Future Prospects

This is another old lecture from my bookmarks. I’m reasonably certain the main reason why I did not blog this earlier is that it’s a rather general and not very detailed overview lecture, so it doesn’t actually contain a lot of new stuff. Hubble’s work, the discovery of the cosmic microwave background, properties of the early universe and how it evolved, discussion of the cosmological constant, dark matter and dark energy, some recent observational results – most of the stuff he talks about should be familiar territory to people interested in the field. Before I watched the lecture I had expected it to include a lot more ‘recent results’ and ‘future prospects’ than were actually included; a big part of the lecture is just an overview of what we’ve learned since the 1930es.

June 7, 2017 Posted by | Astronomy, Lectures, Physics | Leave a comment

Extraordinary Physics with Millisecond Pulsars

A few related links:
Nanograv.org.
Millisecond pulsar.
PSR J0348+0432.
Pulsar timing array.
Detection of Gravitational Waves using Pulsar Timing (paper).
The strong equivalence principle.
European Pulsar Timing Array.
Parkes Observatory.
Gravitational wave.
Gravitational waves from binary supermassive black holes missing in pulsar observations (paper – it’s been a long time since I watched the lecture, but in my bookmarks I noted that some of the stuff included in this publication was covered in the lecture).

May 24, 2017 Posted by | Astronomy, Lectures, Papers, Physics | Leave a comment

Out of this World: A history of Structure in the Universe

This lecture is much less technical than were the last couple of lectures I posted, and if I remember correctly it’s aimed at a general audience (…the sort of ‘general audience’ that attends IAS lectures, but even so…). The lecture itself is quite short, only roughly 35 minutes long, but there’s a long Q&A session afterwards.

May 21, 2017 Posted by | Astronomy, Lectures, Physics | Leave a comment

Hydrodynamical Simulations of Galaxy Formation: Progress, Pitfalls, and Promises

“This calculation was relatively expensive, about 19 million CPU hours were spent on it.”

….

Posts including only one lecture is a recent innovation here on the blog as I have in the past bundled lectures so that a lecture post would include at least 2 or 3 lectures, but I am starting to come around to the idea that these new types of posts are a good idea. I have been going over some old lectures I’ve watched in the past recently, and it turns out that there are quite a few lectures I never got around to blogging; I have mentioned before how the 3 lectures per post format was likely suboptimal, in the sense that they tended to lead to lectures never being covered e.g. because of the long time lag between watching a lecture and blogging it (in the case of book blogging I tend to be much more likely to spend my time covering books I read recently, rather than books I read a while ago, and the same dynamic goes for lectures), and I think this impression is now confirmed.

As some of the lectures I’ll be covering in posts like these in the future are lectures I watched a long time ago my coverage will probably be limited to the actual lectures and the comments I wrote down when I first watched the lecture in question. I don’t want to add a few big lecture posts to just get rid of the backlog, mostly because this blog is obviously not nearly as active as it used to be, and adding single-lecture posts dropwise is an easy (…low-effort) and convenient way for me to keep the blog at least somewhat active. What I wrote down in my comments about the lecture above when I watched it, aside from the quote above, is that considering the very high-level physics included it was sort of surprising to me that the lecture was not so technical as to not be worth watching – but it wasn’t. You’ll certainly not understand all of it, but it’s interesting stuff.

May 18, 2017 Posted by | Astronomy, Lectures, Physics | Leave a comment

Random stuff

It’s been a long time since I last posted one of these posts, so a great number of links of interest has accumulated in my bookmarks. I intended to include a large number of these in this post and this of course means that I surely won’t cover each specific link included in this post in anywhere near the amount of detail it deserves, but that can’t be helped.

i. Autism Spectrum Disorder Grown Up: A Chart Review of Adult Functioning.

“For those diagnosed with ASD in childhood, most will become adults with a significant degree of disability […] Seltzer et al […] concluded that, despite considerable heterogeneity in social outcomes, “few adults with autism live independently, marry, go to college, work in competitive jobs or develop a large network of friends”. However, the trend within individuals is for some functional improvement over time, as well as a decrease in autistic symptoms […]. Some authors suggest that a sub-group of 15–30% of adults with autism will show more positive outcomes […]. Howlin et al. (2004), and Cederlund et al. (2008) assigned global ratings of social functioning based on achieving independence, friendships/a steady relationship, and education and/or a job. These two papers described respectively 22% and 27% of groups of higher functioning (IQ above 70) ASD adults as attaining “Very Good” or “Good” outcomes.”

“[W]e evaluated the adult outcomes for 45 individuals diagnosed with ASD prior to age 18, and compared this with the functioning of 35 patients whose ASD was identified after 18 years. Concurrent mental illnesses were noted for both groups. […] Comparison of adult outcome within the group of subjects diagnosed with ASD prior to 18 years of age showed significantly poorer functioning for those with co-morbid Intellectual Disability, except in the domain of establishing intimate relationships [my emphasis. To make this point completely clear, one way to look at these results is that apparently in the domain of partner-search autistics diagnosed during childhood are doing so badly in general that being intellectually disabled on top of being autistic is apparently conferring no additional disadvantage]. Even in the normal IQ group, the mean total score, i.e. the sum of the 5 domains, was relatively low at 12.1 out of a possible 25. […] Those diagnosed as adults had achieved significantly more in the domains of education and independence […] Some authors have described a subgroup of 15–27% of adult ASD patients who attained more positive outcomes […]. Defining an arbitrary adaptive score of 20/25 as “Good” for our normal IQ patients, 8 of thirty four (25%) of those diagnosed as adults achieved this level. Only 5 of the thirty three (15%) diagnosed in childhood made the cutoff. (The cut off was consistent with a well, but not superlatively, functioning member of society […]). None of the Intellectually Disabled ASD subjects scored above 10. […] All three groups had a high rate of co-morbid psychiatric illnesses. Depression was particularly frequent in those diagnosed as adults, consistent with other reports […]. Anxiety disorders were also prevalent in the higher functioning participants, 25–27%. […] Most of the higher functioning ASD individuals, whether diagnosed before or after 18 years of age, were functioning well below the potential implied by their normal range intellect.”

Related papers: Social Outcomes in Mid- to Later Adulthood Among Individuals Diagnosed With Autism and Average Nonverbal IQ as Children, Adults With Autism Spectrum Disorders.

ii. Premature mortality in autism spectrum disorder. This is a Swedish matched case cohort study. Some observations from the paper:

“The aim of the current study was to analyse all-cause and cause-specific mortality in ASD using nationwide Swedish population-based registers. A further aim was to address the role of intellectual disability and gender as possible moderators of mortality and causes of death in ASD. […] Odds ratios (ORs) were calculated for a population-based cohort of ASD probands (n = 27 122, diagnosed between 1987 and 2009) compared with gender-, age- and county of residence-matched controls (n = 2 672 185). […] During the observed period, 24 358 (0.91%) individuals in the general population died, whereas the corresponding figure for individuals with ASD was 706 (2.60%; OR = 2.56; 95% CI 2.38–2.76). Cause-specific analyses showed elevated mortality in ASD for almost all analysed diagnostic categories. Mortality and patterns for cause-specific mortality were partly moderated by gender and general intellectual ability. […] Premature mortality was markedly increased in ASD owing to a multitude of medical conditions. […] Mortality was significantly elevated in both genders relative to the general population (males: OR = 2.87; females OR = 2.24)”.

“Individuals in the control group died at a mean age of 70.20 years (s.d. = 24.16, median = 80), whereas the corresponding figure for the entire ASD group was 53.87 years (s.d. = 24.78, median = 55), for low-functioning ASD 39.50 years (s.d. = 21.55, median = 40) and high-functioning ASD 58.39 years (s.d. = 24.01, median = 63) respectively. […] Significantly elevated mortality was noted among individuals with ASD in all analysed categories of specific causes of death except for infections […] ORs were highest in cases of mortality because of diseases of the nervous system (OR = 7.49) and because of suicide (OR = 7.55), in comparison with matched general population controls.”

iii. Adhesive capsulitis of shoulder. This one is related to a health scare I had a few months ago. A few quotes:

Adhesive capsulitis (also known as frozen shoulder) is a painful and disabling disorder of unclear cause in which the shoulder capsule, the connective tissue surrounding the glenohumeral joint of the shoulder, becomes inflamed and stiff, greatly restricting motion and causing chronic pain. Pain is usually constant, worse at night, and with cold weather. Certain movements or bumps can provoke episodes of tremendous pain and cramping. […] People who suffer from adhesive capsulitis usually experience severe pain and sleep deprivation for prolonged periods due to pain that gets worse when lying still and restricted movement/positions. The condition can lead to depression, problems in the neck and back, and severe weight loss due to long-term lack of deep sleep. People who suffer from adhesive capsulitis may have extreme difficulty concentrating, working, or performing daily life activities for extended periods of time.”

Some other related links below:

The prevalence of a diabetic condition and adhesive capsulitis of the shoulder.
“Adhesive capsulitis is characterized by a progressive and painful loss of shoulder motion of unknown etiology. Previous studies have found the prevalence of adhesive capsulitis to be slightly greater than 2% in the general population. However, the relationship between adhesive capsulitis and diabetes mellitus (DM) is well documented, with the incidence of adhesive capsulitis being two to four times higher in diabetics than in the general population. It affects about 20% of people with diabetes and has been described as the most disabling of the common musculoskeletal manifestations of diabetes.”

Adhesive Capsulitis (review article).
“Patients with type I diabetes have a 40% chance of developing a frozen shoulder in their lifetimes […] Dominant arm involvement has been shown to have a good prognosis; associated intrinsic pathology or insulin-dependent diabetes of more than 10 years are poor prognostic indicators.15 Three stages of adhesive capsulitis have been described, with each phase lasting for about 6 months. The first stage is the freezing stage in which there is an insidious onset of pain. At the end of this period, shoulder ROM [range of motion] becomes limited. The second stage is the frozen stage, in which there might be a reduction in pain; however, there is still restricted ROM. The third stage is the thawing stage, in which ROM improves, but can take between 12 and 42 months to do so. Most patients regain a full ROM; however, 10% to 15% of patients suffer from continued pain and limited ROM.”

Musculoskeletal Complications in Type 1 Diabetes.
“The development of periarticular thickening of skin on the hands and limited joint mobility (cheiroarthropathy) is associated with diabetes and can lead to significant disability. The objective of this study was to describe the prevalence of cheiroarthropathy in the well-characterized Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) cohort and examine associated risk factors […] This cross-sectional analysis was performed in 1,217 participants (95% of the active cohort) in EDIC years 18/19 after an average of 24 years of follow-up. Cheiroarthropathy — defined as the presence of any one of the following: adhesive capsulitis, carpal tunnel syndrome, flexor tenosynovitis, Dupuytren’s contracture, or a positive prayer sign [related link] — was assessed using a targeted medical history and standardized physical examination. […] Cheiroarthropathy was present in 66% of subjects […] Cheiroarthropathy is common in people with type 1 diabetes of long duration (∼30 years) and is related to longer duration and higher levels of glycemia. Clinicians should include cheiroarthropathy in their routine history and physical examination of patients with type 1 diabetes because it causes clinically significant functional disability.”

Musculoskeletal disorders in diabetes mellitus: an update.
“Diabetes mellitus (DM) is associated with several musculoskeletal disorders. […] The exact pathophysiology of most of these musculoskeletal disorders remains obscure. Connective tissue disorders, neuropathy, vasculopathy or combinations of these problems, may underlie the increased incidence of musculoskeletal disorders in DM. The development of musculoskeletal disorders is dependent on age and on the duration of DM; however, it has been difficult to show a direct correlation with the metabolic control of DM.”

Rheumatic Manifestations of Diabetes Mellitus.

Prevalence of symptoms and signs of shoulder problems in people with diabetes mellitus.

Musculoskeletal Disorders of the Hand and Shoulder in Patients with Diabetes.
“In addition to micro- and macroangiopathic complications, diabetes mellitus is also associated with several musculoskeletal disorders of the hand and shoulder that can be debilitating (1,2). Limited joint mobility, also termed diabetic hand syndrome or cheiropathy (3), is characterized by skin thickening over the dorsum of the hands and restricted mobility of multiple joints. While this syndrome is painless and usually not disabling (2,4), other musculoskeletal problems occur with increased frequency in diabetic patients, including Dupuytren’s disease [“Dupuytren’s disease […] may be observed in up to 42% of adults with diabetes mellitus, typically in patients with long-standing T1D” – link], carpal tunnel syndrome [“The prevalence of [carpal tunnel syndrome, CTS] in patients with diabetes has been estimated at 11–30 % […], and is dependent on the duration of diabetes. […] Type I DM patients have a high prevalence of CTS with increasing duration of disease, up to 85 % after 54 years of DM” – link], palmar flexor tenosynovitis or trigger finger [“The incidence of trigger finger [/stenosing tenosynovitis] is 7–20 % of patients with diabetes comparing to only about 1–2 % in nondiabetic patients” – link], and adhesive capsulitis of the shoulder (5–10). The association of adhesive capsulitis with pain, swelling, dystrophic skin, and vasomotor instability of the hand constitutes the “shoulder-hand syndrome,” a rare but potentially disabling manifestation of diabetes (1,2).”

“The prevalence of musculoskeletal disorders was greater in diabetic patients than in control patients (36% vs. 9%, P < 0.01). Adhesive capsulitis was present in 12% of the diabetic patients and none of the control patients (P < 0.01), Dupuytren’s disease in 16% of diabetic and 3% of control patients (P < 0.01), and flexor tenosynovitis in 12% of diabetic and 2% of control patients (P < 0.04), while carpal tunnel syndrome occurred in 12% of diabetic patients and 8% of control patients (P = 0.29). Musculoskeletal disorders were more common in patients with type 1 diabetes than in those with type 2 diabetes […]. Forty-three patients [out of 100] with type 1 diabetes had either hand or shoulder disorders (37 with hand disorders, 6 with adhesive capsulitis of the shoulder, and 10 with both syndromes), compared with 28 patients [again out of 100] with type 2 diabetes (24 with hand disorders, 4 with adhesive capsulitis of the shoulder, and 3 with both syndromes, P = 0.03).”

Association of Diabetes Mellitus With the Risk of Developing Adhesive Capsulitis of the Shoulder: A Longitudinal Population-Based Followup Study.
“A total of 78,827 subjects with at least 2 ambulatory care visits with a principal diagnosis of DM in 2001 were recruited for the DM group. The non-DM group comprised 236,481 age- and sex-matched randomly sampled subjects without DM. […] During a 3-year followup period, 946 subjects (1.20%) in the DM group and 2,254 subjects (0.95%) in the non-DM group developed ACS. The crude HR of developing ACS for the DM group compared to the non-DM group was 1.333 […] the association between DM and ACS may be explained at least in part by a DM-related chronic inflammatory process with increased growth factor expression, which in turn leads to joint synovitis and subsequent capsular fibrosis.”

It is important to note when interpreting the results of the above paper that these results are based on Taiwanese population-level data, and type 1 diabetes – which is obviously the high-risk diabetes subgroup in this particular context – is rare in East Asian populations (as observed in Sperling et al., “A child in Helsinki, Finland is almost 400 times more likely to develop diabetes than a child in Sichuan, China”. Taiwanese incidence of type 1 DM in children is estimated at ~5 in 100.000).

iv. Parents who let diabetic son starve to death found guilty of first-degree murder. It’s been a while since I last saw one of these ‘boost-your-faith-in-humanity’-cases, but they in my impression do pop up every now and then. I should probably keep at hand one of these articles in case my parents ever express worry to me that they weren’t good parents; they could have done a lot worse…

v. Freedom of medicine. One quote from the conclusion of Cochran’s post:

“[I]t is surely possible to materially improve the efficacy of drug development, of medical research as a whole. We’re doing better than we did 500 years ago – although probably worse than we did 50 years ago. But I would approach it by learning as much as possible about medical history, demographics, epidemiology, evolutionary medicine, theory of senescence, genetics, etc. Read Koch, not Hayek. There is no royal road to medical progress.”

I agree, and I was considering including some related comments and observations about health economics in this post – however I ultimately decided against doing that in part because the post was growing unwieldy; I might include those observations in another post later on. Here’s another somewhat older Westhunt post I at some point decided to bookmark – I in particular like the following neat quote from the comments, which expresses a view I have of course expressed myself in the past here on this blog:

“When you think about it, falsehoods, stupid crap, make the best group identifiers, because anyone might agree with you when you’re obviously right. Signing up to clear nonsense is a better test of group loyalty. A true friend is with you when you’re wrong. Ideally, not just wrong, but barking mad, rolling around in your own vomit wrong.”

vi. Economic Costs of Diabetes in the U.S. in 2012.

“Approximately 59% of all health care expenditures attributed to diabetes are for health resources used by the population aged 65 years and older, much of which is borne by the Medicare program […]. The population 45–64 years of age incurs 33% of diabetes-attributed costs, with the remaining 8% incurred by the population under 45 years of age. The annual attributed health care cost per person with diabetes […] increases with age, primarily as a result of increased use of hospital inpatient and nursing facility resources, physician office visits, and prescription medications. Dividing the total attributed health care expenditures by the number of people with diabetes, we estimate the average annual excess expenditures for the population aged under 45 years, 45–64 years, and 65 years and above, respectively, at $4,394, $5,611, and $11,825.”

“Our logistic regression analysis with NHIS data suggests that diabetes is associated with a 2.4 percentage point increase in the likelihood of leaving the workforce for disability. This equates to approximately 541,000 working-age adults leaving the workforce prematurely and 130 million lost workdays in 2012. For the population that leaves the workforce early because of diabetes-associated disability, we estimate that their average daily earnings would have been $166 per person (with the amount varying by demographic). Presenteeism accounted for 30% of the indirect cost of diabetes. The estimate of a 6.6% annual decline in productivity attributed to diabetes (in excess of the estimated decline in the absence of diabetes) equates to 113 million lost workdays per year.”

vii. Total red meat intake of ≥0.5 servings/d does not negatively influence cardiovascular disease risk factors: a systemically searched meta-analysis of randomized controlled trials.

viii. Effect of longer term modest salt reduction on blood pressure: Cochrane systematic review and meta-analysis of randomised trials. Did I blog this paper at some point in the past? I could not find any coverage of it on the blog when I searched for it so I decided to include it here, even if I have a nagging suspicion I may have talked about these findings before. What did they find? The short version is this:

“A modest reduction in salt intake for four or more weeks causes significant and, from a population viewpoint, important falls in blood pressure in both hypertensive and normotensive individuals, irrespective of sex and ethnic group. Salt reduction is associated with a small physiological increase in plasma renin activity, aldosterone, and noradrenaline and no significant change in lipid concentrations. These results support a reduction in population salt intake, which will lower population blood pressure and thereby reduce cardiovascular disease.”

ix. Some wikipedia links:

Heroic Age of Antarctic Exploration (featured).

Wien’s displacement law.

Kuiper belt (featured).

Treason (one quote worth including here: “Currently, the consensus among major Islamic schools is that apostasy (leaving Islam) is considered treason and that the penalty is death; this is supported not in the Quran but in the Hadith.[42][43][44][45][46][47]“).

Lymphatic filariasis.

File:World map of countries by number of cigarettes smoked per adult per year.

Australian gold rushes.

Savant syndrome (“It is estimated that 10% of those with autism have some form of savant abilities”). A small sidenote of interest to Danish readers: The Danish Broadcasting Corporation recently featured a series about autistics with ‘special abilities’ – the show was called ‘The hidden talents’ (De skjulte talenter), and after multiple people had nagged me to watch it I ended up deciding to do so. Most of the people in that show presumably had some degree of ‘savantism’ combined with autism at the milder end of the spectrum, i.e. Asperger’s. I was somewhat conflicted about what to think about the show and did consider blogging it in detail (in Danish?), but I decided against it. However I do want to add here to Danish readers reading along who’ve seen the show that they would do well to repeatedly keep in mind that a) the great majority of autistics do not have abilities like these, b) many autistics with abilities like these presumably do quite poorly, and c) that many autistics have even greater social impairments than do people like e.g. (the very likeable, I have to add…) Louise Wille from the show).

Quark–gluon plasma.

Simo Häyhä.

Chernobyl liquidators.

Black Death (“Over 60% of Norway’s population died in 1348–1350”).

Renault FT (“among the most revolutionary and influential tank designs in history”).

Weierstrass function (“an example of a pathological real-valued function on the real line. The function has the property of being continuous everywhere but differentiable nowhere”).

W Ursae Majoris variable.

Void coefficient. (“a number that can be used to estimate how much the reactivity of a nuclear reactor changes as voids (typically steam bubbles) form in the reactor moderator or coolant. […] Reactivity is directly related to the tendency of the reactor core to change power level: if reactivity is positive, the core power tends to increase; if it is negative, the core power tends to decrease; if it is zero, the core power tends to remain stable. […] A positive void coefficient means that the reactivity increases as the void content inside the reactor increases due to increased boiling or loss of coolant; for example, if the coolant acts as a neutron absorber. If the void coefficient is large enough and control systems do not respond quickly enough, this can form a positive feedback loop which can quickly boil all the coolant in the reactor. This happened in the RBMK reactor that was destroyed in the Chernobyl disaster.”).

Gregor MacGregor (featured) (“a Scottish soldier, adventurer, and confidence trickster […] MacGregor’s Poyais scheme has been called one of the most brazen confidence tricks in history.”).

Stimming.

Irish Civil War.

March 10, 2017 Posted by | Astronomy, autism, Cardiology, Diabetes, Economics, Epidemiology, History, Infectious disease, Mathematics, Medicine, Papers, Physics, Psychology, Random stuff, Wikipedia | Leave a comment

Galaxies

I have added some observations from the book below, as well as some links covering people/ideas/stuff discussed/mentioned in the book.

“On average, out of every 100 newly born star systems, 60 are binaries and 40 are triples. Solitary stars like the Sun are later ejected from triple systems formed in this way.”

“…any object will become a black hole if it is sufficiently compressed. For any mass, there is a critical radius, called the Schwarzschild radius, for which this occurs. For the Sun, the Schwarzschild radius is just under 3 km; for the Earth, it is just under 1 cm. In either case, if the entire mass of the object were squeezed within the appropriate Schwarzschild radius it would become a black hole.”

“It only became possible to study the centre of our Galaxy when radio telescopes and other instruments that do not rely on visible light became available. There is a great deal of dust in the plane of the Milky Way […] This blocks out visible light. But longer wavelengths penetrate the dust more easily. That is why sunsets are red – short wavelength (blue) light is scattered out of the line of sight by dust in the atmosphere, while the longer wavelength red light gets through to your eyes. So our understanding of the galactic centre is largely based on infrared and radio observations.”

“there is strong evidence that the Milky Way Galaxy is a completely ordinary disc galaxy, a typical representative of its class. Since that is the case, it means that we can confidently use our inside knowledge of the structure and evolution of our own Galaxy, based on close-up observations, to help our understanding of the origin and nature of disc galaxies in general. We do not occupy a special place in the Universe; but this was only finally established at the end of the 20th century. […] in the decades following Hubble’s first measurements of the cosmological distance scale, the Milky Way still seemed like a special place. Hubble’s calculation of the distance scale implied that other galaxies are relatively close to our Galaxy, and so they would not have to be very big to appear as large as they do on the sky; the Milky Way seemed to be by far the largest galaxy in the Universe. We now know that Hubble was wrong. […] the value he initially found for the Hubble Constant was about seven times bigger than the value accepted today. In other words, all the extragalactic distances Hubble inferred were seven times too small. But this was not realized overnight. The cosmological distance scale was only revised slowly, over many decades, as observations improved and one error after another was corrected. […] The importance of determining the cosmological distance scale accurately, more than half a century after Hubble’s pioneering work, was still so great that it was a primary justification for the existence of the Hubble Space Telescope (HST).”

“The key point to grasp […] is that the expansion described by [Einstein’s] equations is an expansion of space as time passes. The cosmological redshift is not a Doppler effect caused by galaxies moving outward through space, as if fleeing from the site of some great explosion, but occurs because the space between the galaxies is stretching. So the spaces between galaxies increase while light is on its way from one galaxy to another. This stretches the light waves to longer wavelengths, which means shifting them towards the red end of the spectrum. […] The second key point about the universal expansion is that it does not have a centre. There is nothing special about the fact that we observe galaxies receding with redshifts proportional to their distances from the Milky Way. […] whichever galaxy you happen to be sitting in, you will see the same thing – redshift proportional to distance.”

“The age of the Universe is determined by studying some of the largest things in the Universe, clusters of galaxies, and analysing their behaviour using the general theory of relativity. Our understanding of how stars work, from which we calculate their ages, comes from studying some of the smallest things in the Universe, the nuclei of atoms, and using the other great theory of 20th-century physics, quantum mechanics, to calculate how nuclei fuse with one another to release the energy that keeps stars shining. The fact that the two ages agree with one another, and that the ages of the oldest stars are just a little bit less than the age of the Universe, is one of the most compelling reasons to think that the whole of 20th-century physics works and provides a good description of the world around us, from the very small scale to the very large scale.”

“Planets are small objects orbiting a large central mass, and the gravity of the Sun dominates their motion. Because of this, the speed with which a planet moves […] is inversely proportional to the square of its distance from the centre of the Solar System. Jupiter is farther from the Sun than we are, so it moves more slowly in its orbit than the Earth, as well as having a larger orbit. But all the stars in the disc of a galaxy move at the same speed. Stars farther out from the centre still have bigger orbits, so they still take longer to complete one circuit of the galaxy. But they are all travelling at essentially the same orbital speed through space.”

“The importance of studying objects at great distances across the Universe is that when we look at an object that is, say, 10 billion light years away, we see it by light which left it 10 billion years ago. This is the ‘look back time’, and it means that telescopes are in a sense time machines, showing us what the Universe was like when it was younger. The light from a distant galaxy is old, in the sense that it has been a long time on its journey; but the galaxy we see using that light is a young galaxy. […] For distant objects, because light has taken a long time on its journey to us, the Universe has expanded significantly while the light was on its way. […] This raises problems defining exactly what you mean by the ‘present distance’ to a remote galaxy”

“Among the many advantages that photographic and electronic recording methods have over the human eye, the most fundamental is that the longer they look, the more they see. Human eyes essentially give us a real-time view of our surroundings, and allow us to see things – such as stars – that are brighter than a certain limit. If an object is too faint to see, once your eyes have adapted to the dark no amount of staring in its direction will make it visible. But the detectors attached to modern telescopes keep on adding up the light from faint sources as long as they are pointing at them. A longer exposure will reveal fainter objects than a short exposure does, as the photons (particles of light) from the source fall on the detector one by one and the total gradually grows.”

“Nobody can be quite sure where the supermassive black holes at the hearts of galaxies today came from, but it seems at least possible that […] merging of black holes left over from the first generation of stars [in the universe] began the process by which supermassive black holes, feeding off the matter surrounding them, formed. […] It seems very unlikely that supermassive black holes formed first and then galaxies grew around them; they must have formed together, in a process sometimes referred to as co-evolution, from the seeds provided by the original black holes of a few hundred solar masses and the raw materials of the dense clouds of baryons in the knots in the filamentary structure. […] About one in a hundred of the galaxies seen at low redshifts are actively involved in the late stages of mergers, but these processes take so little time, compared with the age of the Universe, that the statistics imply that about half of all the galaxies visible nearby are the result of mergers between similarly sized galaxies in the past seven or eight billion years. Disc galaxies like the Milky Way seem themselves to have been built up from smaller sub-units, starting out with the spheroid and adding bits and pieces as time passed. […] there were many more small galaxies when the Universe was young than we see around us today. This is exactly what we would expect if many of the small galaxies have either grown larger through mergers or been swallowed up by larger galaxies.”

Links of interest:

Galaxy (‘featured article’).
Leonard Digges.
Thomas Wright.
William Herschel.
William Parsons.
The Great Debate.
Parallax.
Extinction (astronomy).
Henrietta Swan Leavitt (‘good article’).
Cepheid variable.
Ejnar Hertzsprung. (Before reading this book, I had no idea one of the people behind the famous Hertzsprung–Russell diagram was a Dane. I blame my physics teachers. I was probably told this by one of them, but if the guy in question had been a better teacher, I’d have listened, and I’d have known this.).
Globular cluster (‘featured article’).
Vesto Slipher.
Redshift (‘featured article’).
Refracting telescope/Reflecting telescope.
Disc galaxy.
Edwin Hubble.
Milton Humason.
Doppler effect.
Milky Way.
Orion Arm.
Stellar population.
Sagittarius A*.
Minkowski space.
General relativity (featured).
The Big Bang theory (featured).
Age of the universe.
Malmquist bias.
Type Ia supernova.
Dark energy.
Baryons/leptons.
Cosmic microwave background.
Cold dark matter.
Lambda-CDM model.
Lenticular galaxy.
Active galactic nucleus.
Quasar.
Hubble Ultra-Deep Field.
Stellar evolution.
Velocity dispersion.
Hawking radiation.
Ultimate fate of the universe.

 

February 5, 2017 Posted by | Astronomy, Books, cosmology, Physics | Leave a comment

Random Stuff

i. On the youtube channel of the Institute for Advanced Studies there has been a lot of activity over the last week or two (far more than 100 new lectures have been uploaded, and it seems new uploads are still being added at this point), and I’ve been watching a few of the recently uploaded astrophysics lectures. They’re quite technical, but you can watch them and follow enough of the content to have an enjoyable time despite not understanding everything:


This is a good lecture, very interesting. One major point made early on: “the take-away message is that the most common planet in the galaxy, at least at shorter periods, are planets for which there is no analogue in the solar system. The most common kind of planet in the galaxy is a planet with a radius of two Earth radii.” Another big take-away message is that small planets seem to be quite common (as noted in the conclusions, “16% of Sun-like stars have an Earth-sized planet”).


Of the lectures included in this post this was the one I liked the least; there are too many (‘obstructive’) questions/interactions between lecturer and attendants along the way, and the interactions/questions are difficult to hear/understand. If you consider watching both this lecture and the lecture below, I would say that it would probably be wise to watch the lecture below this one before you watch this one; I concluded that in retrospect some of the observations made early on in the lecture below would have been useful to know about before watching this lecture. (The first half of the lecture below was incidentally to me somewhat easier to follow than was the second half, but especially the first half hour of it is really quite good, despite the bad start (which one can always blame on Microsoft…)).

ii. Words I’ve encountered recently (…or ‘recently’ – it’s been a while since I last posted one of these lists): Divagationsperiphrasis, reedy, architravesettpedipalp, tout, togs, edentulous, moue, tatty, tearaway, prorogue, piscine, fillip, sop, panniers, auxology, roister, prepossessing, cantle, catamite, couth, ordure, biddy, recrudescence, parvenu, scupper, husting, hackle, expatiate, affray, tatterdemalion, eructation, coppice, dekko, scull, fulmination, pollarding, grotty, secateurs, bumf (I must admit that I like this word – it seems fitting, somehow, to use that word for this concept…), durophagy, randy, (brief note to self: Advise people having children who ask me about suggestions for how to name them against using this name (or variants such as Randi), it does not seem like a great idea), effete, apricity, sororal, bint, coition, abaft, eaves, gadabout, lugubriously, retroussé, landlubber, deliquescence, antimacassar, inanition.

iii. “The point of rigour is not to destroy all intuition; instead, it should be used to destroy bad intuition while clarifying and elevating good intuition. It is only with a combination of both rigorous formalism and good intuition that one can tackle complex mathematical problems; one needs the former to correctly deal with the fine details, and the latter to correctly deal with the big picture. Without one or the other, you will spend a lot of time blundering around in the dark (which can be instructive, but is highly inefficient). So once you are fully comfortable with rigorous mathematical thinking, you should revisit your intuitions on the subject and use your new thinking skills to test and refine these intuitions rather than discard them. One way to do this is to ask yourself dumb questions; another is to relearn your field.” (Terry Tao, There’s more to mathematics than rigour and proofs)

iv. A century of trends in adult human height. A figure from the paper (Figure 3 – Change in adult height between the 1896 and 1996 birth cohorts):

elife-13410-fig3-v1

(Click to view full size. WordPress seems to have changed the way you add images to a blog post – if this one is even so annoyingly large, I apologize, I have tried to minimize it while still retaining detail, but the original file is huge). An observation from the paper:

“Men were taller than women in every country, on average by ~11 cm in the 1896 birth cohort and ~12 cm in the 1996 birth cohort […]. In the 1896 birth cohort, the male-female height gap in countries where average height was low was slightly larger than in taller nations. In other words, at the turn of the 20th century, men seem to have had a relative advantage over women in undernourished compared to better-nourished populations.”

I haven’t studied the paper in any detail but intend to do so at a later point in time.

v. I found this paper, on Exercise and Glucose Metabolism in Persons with Diabetes Mellitus, interesting in part because I’ve been very surprised a few times by offhand online statements made by diabetic athletes, who had observed that their blood glucose really didn’t drop all that fast during exercise. Rapid and annoyingly large drops in blood glucose during exercise have been a really consistent feature of my own life with diabetes during adulthood. It seems that there may be big inter-individual differences in terms of the effects of exercise on glucose in diabetics. From the paper:

“Typically, prolonged moderate-intensity aerobic exercise (i.e., 30–70% of one’s VO2max) causes a reduction in glucose concentrations because of a failure in circulating insulin levels to decrease at the onset of exercise.12 During this type of physical activity, glucose utilization may be as high as 1.5 g/min in adolescents with type 1 diabetes13 and exceed 2.0 g/min in adults with type 1 diabetes,14 an amount that quickly lowers circulating glucose levels. Persons with type 1 diabetes have large interindividual differences in blood glucose responses to exercise, although some intraindividual reproducibility exists.15 The wide ranging glycemic responses among individuals appears to be related to differences in pre-exercise blood glucose concentrations, the level of circulating counterregulatory hormones and the type/duration of the activity.2

August 13, 2016 Posted by | Astronomy, Demographics, Diabetes, language, Lectures, Mathematics, Physics, Random stuff | Leave a comment

Random stuff

I find it difficult to find the motivation to finish the half-finished drafts I have lying around, so this will have to do. Some random stuff below.

i.

(15.000 views… In some sense that seems really ‘unfair’ to me, but on the other hand I doubt neither Beethoven nor Gilels care; they’re both long dead, after all…)

ii. New/newish words I’ve encountered in books, on vocabulary.com or elsewhere:

Agleyperipeteia, disseverhalidom, replevinsocage, organdie, pouffe, dyarchy, tauricide, temerarious, acharnement, cadger, gravamen, aspersion, marronage, adumbrate, succotash, deuteragonist, declivity, marquetry, machicolation, recusal.

iii. A lecture:

It’s been a long time since I watched it so I don’t have anything intelligent to say about it now, but I figured it might be of interest to one or two of the people who still subscribe to the blog despite the infrequent updates.

iv. A few wikipedia articles (I won’t comment much on the contents or quote extensively from the articles the way I’ve done in previous wikipedia posts – the links shall have to suffice for now):

Duverger’s law.

Far side of the moon.

Preference falsification.

Russian political jokes. Some of those made me laugh (e.g. this one: “A judge walks out of his chambers laughing his head off. A colleague approaches him and asks why he is laughing. “I just heard the funniest joke in the world!” “Well, go ahead, tell me!” says the other judge. “I can’t – I just gave someone ten years for it!”).

Political mutilation in Byzantine culture.

v. World War 2, if you think of it as a movie, has a highly unrealistic and implausible plot, according to this amusing post by Scott Alexander. Having recently read a rather long book about these topics, one aspect I’d have added had I written the piece myself would be that an additional factor making the setting seem even more implausible is how so many presumably quite smart people were so – what at least in retrospect seems – unbelievably stupid when it came to Hitler’s ideas and intentions before the war. Going back to Churchill’s own life I’d also add that if you were to make a movie about Churchill’s life during the war, which you could probably relatively easily do if you were to just base it upon his own copious and widely shared notes, then it could probably be made into a quite decent movie. His own comments, remarks, and observations certainly made for a great book.

May 15, 2016 Posted by | Astronomy, Computer science, History, language, Lectures, Mathematics, Music, Random stuff, Russia, Wikipedia | Leave a comment

Physically Speaking: A Dictionary of Quotations on Physics and Astronomy

Here’s my goodreads review of the book. As mentioned in the review, the book was overall a slightly disappointing read – but there were some decent quotes included in the book, and I decided that I ought to post a post with some sample quotes here as it would be a relatively easy post to write. Do note while reading this post that the book had a lot of bad quotes, so you should not take the sample quotes I’ve posted below to be representative of the book’s coverage in general.

i. “The aim of science is to seek the simplest explanation of complex facts. We are apt to fall into the error of thinking that the facts are simple because simplicity is the goal of our quest. The guiding motto in the life of every natural philosopher should be “Seek simplicity and distrust it.”” (Alfred North Whitehead)

ii. “Poor data and good reasoning give poor results. Good data and poor reasoning give poor results. Poor data and poor reasoning give rotten results.” (Edmund C. Berkeley)

iii. “By no process of sound reasoning can a conclusion drawn from limited data have more than a limited application.” (J.W. Mellor)

iv. “The energy produced by the breaking down of the atom is a very poor kind of thing. Anyone who expects a source of power from the transformation of these atoms is talking moonshine.” (Ernest Rutherford, 1933).

v. “An experiment is a question which science poses to Nature, and a measurement is the recording of Nature’s answer.” (Max Planck)

vi. “A fact doesn’t have to be understood to be true.” (Heinlein)

vii. “God was invented to explain mystery. God is always invented to explain those things that you do not understand. Now, when you finally discover how something works, you get some laws which you’re taking away from God; you don’t need him anymore. But you need him for the other mysteries. So therefore you leave him to create the universe because we haven’t figured that out yet; you need him for understanding those things which you don’t believe the laws will explain, such as consciousness, or why you only live to a certain length of time – life and death – stuff like that. God is always associated with those things that you do not understand.” (Feynman)

viii. “Hypotheses are the scaffolds which are erected in front of a building and removed when the building is completed. They are indispensable to the worker; but he must not mistake the scaffolding for the building.” (Goethe)

ix. “We are to admit no more cause of natural things than such as are both true and sufficient to explain their appearances.” (Newton)

x. “It is the province of knowledge to speak and it is the privilege of wisdom to listen.” (Oliver Wendell Holmes)

xi. “Light crosses space with the prodigious velocity of 6,000 leagues per second.

La Science Populaire
April 28, 1881″

“A typographical error slipped into our last issue that is important to correct. The speed of light is 76,000 leagues per hour – and not 6,000.

La Science Populaire

May 19, 1881″

“A note correcting a first error appeared in our issue number 68, indicating that the speed of light is 76,000 leagues per hour. Our readers have corrected this new error. The speed of light is approximately 76,000 leagues per second.

La Science Populaire
June 16,1881″

xii. “All models are wrong but some are useful.” (G. E. P. Box)

xiii. “the downward movement of a mass of gold or lead, or of any other body endowed with weight, is quicker in proportion to its size.” (Aristotle)

xiv. “those whom devotion to abstract discussions has rendered unobservant of the facts are too ready to dogmatize on the basis of a few observations” (-ll-).

xv. “it may properly be asked whether science can be undertaken without taking the risk of skating on the possibly thin ice of supposition. The important thing to know is when one is on the more solid ground of observation and when one is on the ice.” (W. M. O’Neil)

xvi. “If I could remember the names of all these particles, I’d be a botanist.” (Enrico Fermi)

xvii. “Theoretical physicists are accustomed to living in a world which is removed from tangible objects by two levels of abstraction. From tangible atoms we move by one level of abstraction to invisible fields and particles. A second level of abstraction takes us from fields and particles to the symmetry-groups by which fields and particles are related. The superstring theory takes us beyond symmetry-groups to two further levels of abstraction. The third level of abstraction is the interpretation of symmetry-groups in terms of states in ten-dimensional space-time. The fourth level is the world of the superstrings by whose dynamical behavior the states are defined.” (Freeman Dyson)

xviii. “Space tells matter how to move . . . and matter tells space how to curve.” (John Wheeler)

xix. “the universe is not a rigid and inimitable edifice where independent matter is housed in independent space and time; it is an amorphous continuum, without any fixed architecture, plastic and variable, constantly subject to change and distortion. Wherever there is matter and motion, the continuum is disturbed. Just as a fish swimming in the sea agitates the water around it, so a star, a comet, or a galaxy distorts the geometry of the space-time through which it moves.” (Lincoln Barnett)

xx. “most physicists today place the probability of the existence of tachyons only slightly higher than the existence of unicorns” (Nick Herbert).

December 19, 2015 Posted by | Astronomy, Books, Physics, Quotes/aphorisms, Religion | Leave a comment

A few lectures

I was debating whether to post this, but considering how long it’s been since my last post I decided to do it. A large number of lectures have recently been uploaded by the Institute for Advanced Studies, and despite the fact that most of my ‘blogging-related activities’ these days relate to book reading I have watched a few of those lectures, and so I decided to post a couple of the lectures here:

I liked this lecture. Part II of the lecture in particular, starting around the 38 minute mark, dealt with stuff reasonably closely related to things I’d read about before (‘relatively’…) recently, back when I read Lammer’s text (blog coverage here); so although I didn’t remember the stuff covered in Lammer’s text in too much detail, it was definitely helpful to have worked with this stuff before. However I do believe you can watch the lecture and sort of understand what she’s talking about without knowing a great deal about these topics, at least if you don’t care too much about understanding all the details (I’d note that there are a lot of things going on ‘behind the scenes’ here, and that you can say a lot of stuff about topics closely related to this talk, like outgassing processes and how they relate to things like volcanism as well as e.g. the dynamic interactions between atmospheric molecules and the solar wind taking place in the early stages of stellar evolution). As is always the case for IAS lectures it’s really hard to hear the questions being asked and that’s annoying, but actually I think miss Schilchting is reasonably good at repeating the question or sort of answer them in a way that enables you to gather what’s ‘going on’; at least the fact that you can’t hear the questions is in my opinion a somewhat bigger problem in the lecture below (relatedly you can actually also see where the laser pointer is pointing in this lecture, at least some of the time – you can’t in the lecture below).

As mentioned this one was harder to follow, at least for me.

I hope to find time to blog a bit more in the days to come. One of several reasons why I’ve not blogged more than I have during the last weeks is that I recently realized that if I put in a bit of effort I’d be able to reach 150 books this year (I’m currently at 143 books, but very close to 144), with 50 non-fiction books (I think going for 52 would be a bit too much, but I’m not ruling it out yet – I’m currently at 47 non-fiction books (…but very close to 48)). I should note that I update the book post to which I link above much more often than I update ‘the blog’ in general with new posts. The reason why the ‘read 150 books this year goal’ is relevant is of course that every time I blog a book here on the blog, this takes away a substantial amount of time which I can’t spend actually reading books. Goodreads incidentally have recently made a nice ‘book of the year’ profile where you can see more details about the books I’ve read etc. From that profile I realized that my implicit working goal of reading 100 pages/day over the year has already been met (I’m currently at ~42.000 pages).

December 18, 2015 Posted by | Astronomy, Books, Lectures, Physics | Leave a comment

A couple of lectures and a little bit of random stuff

i. Two lectures from the Institute for Advanced Studies:

The IAS has recently uploaded a large number of lectures on youtube, and the ones I blog here are a few of those where you can actually tell from the title what the lecture is about; I find it outright weird that these people don’t include the topic covered in the lecture in their lecture titles.

As for the video above, as usual for the IAS videos it’s annoying that you can’t hear the questions asked by the audience, but the sound quality of this video is at least quite a bit better than the sound quality of the video below (which has a couple of really annoying sequences, in particular around the 15-16 minutes mark (it gets better), where the image is also causing problems, and in the last couple of minutes of the Q&A things are also not exactly optimal as the lecturer leaves the area covered by the camera in order to write something on the blackboard – but you don’t know what he’s writing and you can’t see the lecturer, because the camera isn’t following him). I found most of the above lecture easier to follow than I did the lecture posted below, though in either case you’ll probably not understand all of it unless you’re an astrophysicist – you definitely won’t in case of the latter lecture. I found it helpful to look up a few topics along the way, e.g. the wiki articles about the virial theorem (/also dealing with virial mass/radius), active galactic nucleus (this is the ‘AGN’ she refers to repeatedly), and the Tully–Fisher relation.

Given how many questions are asked along the way it’s really annoying that you in most cases can’t hear what people are asking about – this is definitely an area where there’s room for improvement in the context of the IAS videos. The lecture was not easy to follow but I figured along the way that I understood enough of it to make it worth watching the lecture to the end (though I’d say you’ll not miss much if you stop after the lecture – around the 1.05 hours mark – and skip the subsequent Q&A). I’ve relatively recently read about related topics, e.g. pulsar formation and wave- and fluid dynamics, and if I had not I probably would not have watched this lecture to the end.

ii. A vocabulary.com update. I’m slowly working my way up to the ‘Running Dictionary’ rank (I’m only a walking dictionary at this point); here’s some stuff from my progress page:

Vocab
I recently learned from a note added to a list that I’ve actually learned a very large proportion of all words available on vocabulary.com, which probably also means that I may have been too harsh on the word selection algorithm in past posts here on the blog; if there aren’t (/m)any new words left to learn it should not be surprising that the algorithm presents me with words I’ve already mastered, and it’s not the algorithm’s fault that there aren’t more words available for me to learn (well, it is to the extent that you’re of the opinion that questions should be automatically created by the algorithm as well, but I don’t think we’re quite there yet at this point). The aforementioned note was added in June, and here’s the important part: “there are words on your list that Vocabulary.com can’t teach yet. Vocabulary.com can teach over 12,000 words, but sadly, these aren’t among them”. ‘Over 12.000’ – and I’ve mastered 11.300. When the proportion of mastered words is this high, not only will the default random word algorithm mostly present you with questions related to words you’ve already mastered; but it actually also starts to get hard to find lists with many words you’ve not already mastered – I’ll often load lists with one hundred words and then realize that I’ve mastered every word on the list. This is annoying if you have a desire to continually be presented with both new words as well as old ones. Unless vocabulary.com increases the rate with which they add new words I’ll run out of new words to learn, and if that happens I’m sure it’ll be much more difficult for me to find motivation to use the site.

With all that stuff out of the way, if you’re not a regular user of the site I should note – again – that it’s an excellent resource if you desire to increase your vocabulary. Below is a list of words I’ve encountered on the site in recent weeks(/months?):

Copaceticfrumpyelisiontermagantharridanquondam, funambulist, phantasmagoriaeyelet, cachinnate, wilt, quidnunc, flocculent, galoot, frangible, prevaricate, clarion, trivet, noisome, revenant, myrmidon (I have included this word once before in a post of this type, but it is in my opinion a very nice word with which more people should be familiar…), debenture, teeter, tart, satiny, romp, auricular, terpsichorean, poultice, ululation, fusty, tangy, honorarium, eyas, bumptious, muckraker, bayou, hobble, omphaloskepsis, extemporize, virago, rarefaction, flibbertigibbet, finagle, emollient.

iii. I don’t think I’d do things exactly the way she’s suggesting here, but the general idea/approach seems to me appealing enough for it to be worth at least keeping in mind if I ever decide to start dating/looking for a partner.

iv. Some wikipedia links:

Tarrare (featured). A man with odd eating habits and an interesting employment history (“Dr. Courville was keen to continue his investigations into Tarrare’s eating habits and digestive system, and approached General Alexandre de Beauharnais with a suggestion that Tarrare’s unusual abilities and behaviour could be put to military use.[9] A document was placed inside a wooden box which was in turn fed to Tarrare. Two days later, the box was retrieved from his excrement, with the document still in legible condition.[9][17] Courville proposed to de Beauharnais that Tarrare could thus serve as a military courier, carrying documents securely through enemy territory with no risk of their being found if he were searched.” Yeah…).

Cauda equina syndromeCastleman’s disease, Astereognosis, Familial dysautonomia, Homonymous hemianopsia, Amaurosis fugax. All of these are of course related to content covered in the Handbook.

1740 Batavia massacre (featured).

v. I am also fun.

October 30, 2015 Posted by | Astronomy, History, Immunology, language, Lectures, Medicine, Neurology, Personal, Physics, Random stuff, Wikipedia | Leave a comment

A few lectures

The Institute for Advanced Studies recently released a number of new lectures on youtube and I’ve watched a few of them.

Both this lecture and the one below start abruptly with no introduction, but I don’t think much stuff was covered before the beginning of this recording. The stuff in both lectures is ‘reasonably’ closely related to content covered in the book on pulsars/supernovae/neutron stars by McNamara which I recently finished (goodreads link) (…for some definitions of ‘reasonably’ I should perhaps add – it’s not that closely related, and for example Ramirez’ comment around the 50 minute mark that they’re disregarding magnetic fields seemed weird to me in the context of McNamara’s coverage). The first lecture was definitely much easier for me to follow than was the last one. The fact that you can’t hear the questions being asked I found annoying, but there aren’t that many questions being asked along the way. I was surprised to learn via google that Ramirez seems to be affiliated with the Niels Bohr Institute of Copenhagen (link).

Here’s a third lecture from the IAS:

I really didn’t think much of this lecture, but some of you might like it. It’s very non-technical compared to the first two lectures above, and unlike them the video recording did not start abruptly in the ‘middle’ of the lecture – which in this case on the other hand also means that you can actually easily skip the first 6-7 minutes without missing out on anything. Given the stuff he talks about in roughly the last 10 minutes of the lecture (aside from the concluding remarks) this is probably a reasonable place to remind you that Feynman’s lectures on the character of physical law are available on youtube and uploaded on this blog (see the link). If you have not watched those lectures, I actually think you should probably do that before watching a lecture like the one above – it’s in all likelihood a better use of your time. If you’re curious about things like cosmological scales and haven’t watched any of videos in the Khan Academy cosmology and astronomy lecture series, this is incidentally a good place to go have a look; the first few videos in the lecture series are really nice. Tegmark talks in his lecture about how we’ve underestimated how large the universe is, but I don’t really think the lecture adequately conveys just how mindbogglingly large the universe is, and I think Salman Khan’s lectures are much better if you want to get ‘a proper perspective’ of these things, to the extent that obtaining a ‘proper perspective’ is even possible given the limitations of the human mind.

Lastly, a couple more lectures from khanacademymedicine:

This is a neat little overview, especially if you’re unfamiliar with the topic.

July 24, 2015 Posted by | Astronomy, Lectures, Medicine, Pharmacology, Physics, Psychology | Leave a comment

A few lectures

This one is not quite new, but I have never seen it or blogged it before. The sound is not completely optimal and as is so often the case for lectures like these it’s at times slightly annoying that you can’t tell what she’s pointing at when she’s talking about the slides, but these issues are relatively minor and should not keep you from watching the lecture.

This is a really nice introduction to some main ideas in the Nimzo Indian defence.

June 10, 2015 Posted by | Astronomy, Chess, Lectures | Leave a comment

Stuff

i. World Happiness Report 2013. A few figures from the publication:

Fig 2.2

Fig 2.4

Fig 2.5

ii. Searching for Explanations: How the Internet Inflates Estimates of Internal Knowledge.

“As the Internet has become a nearly ubiquitous resource for acquiring knowledge about the world, questions have arisen about its potential effects on cognition. Here we show that searching the Internet for explanatory knowledge creates an illusion whereby people mistake access to information for their own personal understanding of the information. Evidence from 9 experiments shows that searching for information online leads to an increase in self-assessed knowledge as people mistakenly think they have more knowledge “in the head,” even seeing their own brains as more active as depicted by functional MRI (fMRI) images.”

A little more from the paper:

“If we go to the library to find a fact or call a friend to recall a memory, it is quite clear that the information we seek is not accessible within our own minds. When we go to the Internet in search of an answer, it seems quite clear that we are we consciously seeking outside knowledge. In contrast to other external sources, however, the Internet often provides much more immediate and reliable access to a broad array of expert information. Might the Internet’s unique accessibility, speed, and expertise cause us to lose track of our reliance upon it, distorting how we view our own abilities? One consequence of an inability to monitor one’s reliance on the Internet may be that users become miscalibrated regarding their personal knowledge. Self-assessments can be highly inaccurate, often occurring as inflated self-ratings of competence, with most people seeing themselves as above average [here’s a related link] […] For example, people overestimate their own ability to offer a quality explanation even in familiar domains […]. Similar illusions of competence may emerge as individuals become immersed in transactive memory networks. They may overestimate the amount of information contained in their network, producing a “feeling of knowing,” even when the content is inaccessible […]. In other words, they may conflate the knowledge for which their partner is responsible with the knowledge that they themselves possess (Wegner, 1987). And in the case of the Internet, an especially immediate and ubiquitous memory partner, there may be especially large knowledge overestimations. As people underestimate how much they are relying on the Internet, success at finding information on the Internet may be conflated with personally mastered information, leading Internet users to erroneously include knowledge stored outside their own heads as their own. That is, when participants access outside knowledge sources, they may become systematically miscalibrated regarding the extent to which they rely on their transactive memory partner. It is not that they misattribute the source of their knowledge, they could know full well where it came from, but rather they may inflate the sense of how much of the sum total of knowledge is stored internally.

We present evidence from nine experiments that searching the Internet leads people to conflate information that can be found online with knowledge “in the head.” […] The effect derives from a true misattribution of the sources of knowledge, not a change in understanding of what counts as internal knowledge (Experiment 2a and b) and is not driven by a “halo effect” or general overconfidence (Experiment 3). We provide evidence that this effect occurs specifically because information online can so easily be accessed through search (Experiment 4a–c).”

iii. Some words I’ve recently encountered on vocabulary.com: hortatory, adduce, obsequious, enunciate, ineluctable, guerdon, chthonic, condignphilippic, coruscate, exceptionable, colophon, lapidary, rubicund, frumpish, raiment, prorogue, sonorous, metonymy.

iv.

v. I have no idea how accurate this test of chess strength is, (some people in this thread argue that there are probably some calibration issues at the low end) but I thought I should link to it anyway. I’d be very cautious about drawing strong conclusions about over-the-board strength without knowing how they’ve validated the tool. In over-the-board chess you have at minimum a couple of minutes/move on average and this tool never gives you more than 30 seconds, so some slow players will probably suffer using this tool (I’d imagine this is why u/ViktorVamos got such a low estimate). For what it’s worth my Elo estimate was 2039 (95% CI: 1859, 2220).

In related news, I recently defeated my first IM – Pablo Garcia Castro – in a blitz (3 minutes/player) game. It actually felt a bit like an anticlimax and afterwards I was thinking that it would probably have felt like a bigger deal if I’d not lately been getting used to winning the occasional bullet game against IMs on the ICC. Actually I think my two wins against WIM Shiqun Ni during the same bullet session at the time felt like a bigger accomplishment, because that specific session was played during the Women’s World Chess Championship and I realized while looking up my opponent that this woman was actually stronger than one of the contestants who made it to the quarter-finals in that event (Meri Arabidze). On the other hand bullet isn’t really chess, so…

April 15, 2015 Posted by | Astronomy, Chess, Lectures, Papers, Psychology | 2 Comments

Some links (Open Thread?)

It’s been quite a while since the last time I posted a ‘here’s some interesting stuff I’ve found online’-post, so I’ll do that now even though I actually don’t spend much time randomly looking around for interesting stuff online these days. I added some wikipedia links I’d saved for a ‘wikipedia articles of interest’-post because it usually takes quite a bit of time to write a standard wikipedia post (as it takes time to figure out what to include and what not to include in the coverage) and I figured that if I didn’t add those links here I’d never get around to blogging them.

i. Battle of Dyrrhachium. Found via this link, which has a lot of stuff.

ii. An AMA by someone who claims to have succeeded in faking his own death.

iii. I found this article about the so-called “Einstellung” effect in chess interesting. I’m however not sure how important this stuff really is. I don’t think it’s sub-optimal for a player to spend a significant amount of time in positions like the ones they analyzed on ideas that don’t work, because usually you’ll only have to spot one idea that does to win the game. It’s obvious that one can argue people spend ‘too much’ time looking for a winning combination in positions where by design no winning combinations exist, but the fact of the matter is that in positions where ‘familiar patterns’ pop up winning resources often do exist, and you don’t win games by overlooking those or by failing to spend time looking for them; occasional suboptimal moves in some contexts may be a reasonable price to pay for increasing your likelihood of finding/playing the best/winning moves when those do exist. Here’s a slightly related link dealing with the question of the potential number of games/moves in chess. Here’s a good wiki article about pawn structures, and here’s one about swindles in chess. I incidentally very recently became a member of the ICC, and I’m frankly impressed with the player pool – which is huge and includes some really strong players (players like Morozevich and Tomashevsky seem to play there regularly). Since I started out on the site I’ve already beaten 3 IMs in bullet and lost a game against Islandic GM Henrik Danielsen. The IMs I’ve beaten were far from the strongest players in the player pool, but in my experience you don’t get to play titled players nearly as often as that on other sites if you’re at my level.

iv. A picture of the Andromeda galaxy. A really big picture. Related link here.

v. You may already have seen this one, but in case you have not: A Philosopher Walks Into A Coffee Shop. More than one of these made me laugh out loud. If you like the post you should take a look at the comments as well, there are some brilliant ones there as well.

vi. Amdahl’s law.

vii. Eigendecomposition of a matrix. On a related note I’m currently reading Imboden and Pfenninger’s Introduction to Systems Analysis (which goodreads for some reason has listed under a wrong title, as the goodreads book title is really the subtitle of the book), and today I had a look at the wiki article on Jacobian matrices and determinants for that reason (the book is about as technical as you’d expect from a book with a title like that).

viii. If you’ve been wondering how I’ve found the quotes I’ve posted here on this blog (I’ve posted roughly 150 posts with quotes so far), links like these are very useful.

ix. Geology of the Yosemite area.

February 7, 2015 Posted by | Astronomy, Chess, Geology, History, Mathematics, Open Thread, Random stuff, Wikipedia | Leave a comment

Wikipedia articles of interest

i. Pendle witches.

“The trials of the Pendle witches in 1612 are among the most famous witch trials in English history, and some of the best recorded of the 17th century. The twelve accused lived in the area around Pendle Hill in Lancashire, and were charged with the murders of ten people by the use of witchcraft. All but two were tried at Lancaster Assizes on 18–19 August 1612, along with the Samlesbury witches and others, in a series of trials that have become known as the Lancashire witch trials. One was tried at York Assizes on 27 July 1612, and another died in prison. Of the eleven who went to trial – nine women and two men – ten were found guilty and executed by hanging; one was found not guilty.

The official publication of the proceedings by the clerk to the court, Thomas Potts, in his The Wonderfull Discoverie of Witches in the Countie of Lancaster, and the number of witches hanged together – nine at Lancaster and one at York – make the trials unusual for England at that time. It has been estimated that all the English witch trials between the early 15th and early 18th centuries resulted in fewer than 500 executions; this series of trials accounts for more than two per cent of that total.”

“One of the accused, Demdike, had been regarded in the area as a witch for fifty years, and some of the deaths the witches were accused of had happened many years before Roger Nowell started to take an interest in 1612.[13] The event that seems to have triggered Nowell’s investigation, culminating in the Pendle witch trials, occurred on 21 March 1612.[14]

On her way to Trawden Forest, Demdike’s granddaughter, Alizon Device, encountered John Law, a pedlar from Halifax, and asked him for some pins.[15] Seventeenth-century metal pins were handmade and relatively expensive, but they were frequently needed for magical purposes, such as in healing – particularly for treating warts – divination, and for love magic, which may have been why Alizon was so keen to get hold of them and why Law was so reluctant to sell them to her.[16] Whether she meant to buy them, as she claimed, and Law refused to undo his pack for such a small transaction, or whether she had no money and was begging for them, as Law’s son Abraham claimed, is unclear.[17] A few minutes after their encounter Alizon saw Law stumble and fall, perhaps because he suffered a stroke; he managed to regain his feet and reach a nearby inn.[18] Initially Law made no accusations against Alizon,[19] but she appears to have been convinced of her own powers; when Abraham Law took her to visit his father a few days after the incident, she reportedly confessed and asked for his forgiveness.[20]

Alizon Device, her mother Elizabeth, and her brother James were summoned to appear before Nowell on 30 March 1612. Alizon confessed that she had sold her soul to the Devil, and that she had told him to lame John Law after he had called her a thief. Her brother, James, stated that his sister had also confessed to bewitching a local child. Elizabeth was more reticent, admitting only that her mother, Demdike, had a mark on her body, something that many, including Nowell, would have regarded as having been left by the Devil after he had sucked her blood.”

“The Pendle witches were tried in a group that also included the Samlesbury witches, Jane Southworth, Jennet Brierley, and Ellen Brierley, the charges against whom included child murder and cannibalism; Margaret Pearson, the so-called Padiham witch, who was facing her third trial for witchcraft, this time for killing a horse; and Isobel Robey from Windle, accused of using witchcraft to cause sickness.[33]

Some of the accused Pendle witches, such as Alizon Device, seem to have genuinely believed in their guilt, but others protested their innocence to the end.”

“Nine-year-old Jennet Device was a key witness for the prosecution, something that would not have been permitted in many other 17th-century criminal trials. However, King James had made a case for suspending the normal rules of evidence for witchcraft trials in his Daemonologie.[42] As well as identifying those who had attended the Malkin Tower meeting, Jennet also gave evidence against her mother, brother, and sister. […] When Jennet was asked to stand up and give evidence against her mother, Elizabeth began to scream and curse her daughter, forcing the judges to have her removed from the courtroom before the evidence could be heard.[48] Jennet was placed on a table and stated that she believed her mother had been a witch for three or four years. She also said her mother had a familiar called Ball, who appeared in the shape of a brown dog. Jennet claimed to have witnessed conversations between Ball and her mother, in which Ball had been asked to help with various murders. James Device also gave evidence against his mother, saying he had seen her making a clay figure of one of her victims, John Robinson.[49] Elizabeth Device was found guilty.[47]

James Device pleaded not guilty to the murders by witchcraft of Anne Townley and John Duckworth. However he, like Chattox, had earlier made a confession to Nowell, which was read out in court. That, and the evidence presented against him by his sister Jennet, who said that she had seen her brother asking a black dog he had conjured up to help him kill Townley, was sufficient to persuade the jury to find him guilty.[50][51]

“Many of the allegations made in the Pendle witch trials resulted from members of the Demdike and Chattox families making accusations against each other. Historian John Swain has said that the outbreaks of witchcraft in and around Pendle demonstrate the extent to which people could make a living either by posing as a witch, or by accusing or threatening to accuse others of being a witch.[17] Although it is implicit in much of the literature on witchcraft that the accused were victims, often mentally or physically abnormal, for some at least, it may have been a trade like any other, albeit one with significant risks.[74] There may have been bad blood between the Demdike and Chattox families because they were in competition with each other, trying to make a living from healing, begging, and extortion.”

ii. Kullback–Leibler divergence.

This article is the only one of the five ‘main articles’ in this post which is not a featured article. I looked this one up because the Burnham & Anderson book I’m currently reading talks about this stuff quite a bit. The book will probably be one of the most technical books I’ll read this year, and I’m not sure how much of it I’ll end up covering here. Basically most of the book deals with the stuff ‘covered’ in the (very short) ‘Relationship between models and reality’ section of the wiki article. There are a lot of details the article left out… The same could be said about the related wiki article about AIC (both articles incidentally include the book in their references).

iii Atmosphere of Jupiter.

The first thing that would spring to mind if someone asked me what I knew about it would probably be something along the lines of: “…well, it’s huge…”

Jupiter-Earth-Spot_comparison

…and it is. But we know a lot more than that – some observations from the article:

“The atmosphere of Jupiter is the largest planetary atmosphere in the Solar System. It is mostly made of molecular hydrogen and helium in roughly solar proportions; other chemical compounds are present only in small amounts […] The atmosphere of Jupiter lacks a clear lower boundary and gradually transitions into the liquid interior of the planet. […] The Jovian atmosphere shows a wide range of active phenomena, including band instabilities, vortices (cyclones and anticyclones), storms and lightning. […] Jupiter has powerful storms, always accompanied by lightning strikes. The storms are a result of moist convection in the atmosphere connected to the evaporation and condensation of water. They are sites of strong upward motion of the air, which leads to the formation of bright and dense clouds. The storms form mainly in belt regions. The lightning strikes on Jupiter are hundreds of times more powerful than those seen on Earth.” [However do note that later on in the article it is stated that: “On Jupiter lighting strikes are on average a few times more powerful than those on Earth.”]

“The composition of Jupiter’s atmosphere is similar to that of the planet as a whole.[1] Jupiter’s atmosphere is the most comprehensively understood of those of all the gas giants because it was observed directly by the Galileo atmospheric probe when it entered the Jovian atmosphere on December 7, 1995.[26] Other sources of information about Jupiter’s atmospheric composition include the Infrared Space Observatory (ISO),[27] the Galileo and Cassini orbiters,[28] and Earth-based observations.”

“The visible surface of Jupiter is divided into several bands parallel to the equator. There are two types of bands: lightly colored zones and relatively dark belts. […] The alternating pattern of belts and zones continues until the polar regions at approximately 50 degrees latitude, where their visible appearance becomes somewhat muted.[30] The basic belt-zone structure probably extends well towards the poles, reaching at least to 80° North or South.[5]

The difference in the appearance between zones and belts is caused by differences in the opacity of the clouds. Ammonia concentration is higher in zones, which leads to the appearance of denser clouds of ammonia ice at higher altitudes, which in turn leads to their lighter color.[15] On the other hand, in belts clouds are thinner and are located at lower altitudes.[15] The upper troposphere is colder in zones and warmer in belts.[5] […] The Jovian bands are bounded by zonal atmospheric flows (winds), called jets. […] The location and width of bands, speed and location of jets on Jupiter are remarkably stable, having changed only slightly between 1980 and 2000. […] However bands vary in coloration and intensity over time […] These variations were first observed in the early seventeenth century.”

“Jupiter radiates much more heat than it receives from the Sun. It is estimated that the ratio between the power emitted by the planet and that absorbed from the Sun is 1.67 ± 0.09.”

iv. Wife selling (English custom).

Wife selling in England was a way of ending an unsatisfactory marriage by mutual agreement that probably began in the late 17th century, when divorce was a practical impossibility for all but the very wealthiest. After parading his wife with a halter around her neck, arm, or waist, a husband would publicly auction her to the highest bidder. […] Although the custom had no basis in law and frequently resulted in prosecution, particularly from the mid-19th century onwards, the attitude of the authorities was equivocal. At least one early 19th-century magistrate is on record as stating that he did not believe he had the right to prevent wife sales, and there were cases of local Poor Law Commissioners forcing husbands to sell their wives, rather than having to maintain the family in workhouses.”

“Until the passing of the Marriage Act of 1753, a formal ceremony of marriage before a clergyman was not a legal requirement in England, and marriages were unregistered. All that was required was for both parties to agree to the union, so long as each had reached the legal age of consent,[8] which was 12 for girls and 14 for boys.[9] Women were completely subordinated to their husbands after marriage, the husband and wife becoming one legal entity, a legal status known as coverture. […] Married women could not own property in their own right, and were indeed themselves the property of their husbands. […] Five distinct methods of breaking up a marriage existed in the early modern period of English history. One was to sue in the ecclesiastical courts for separation from bed and board (a mensa et thoro), on the grounds of adultery or life-threatening cruelty, but it did not allow a remarriage.[11] From the 1550s, until the Matrimonial Causes Act became law in 1857, divorce in England was only possible, if at all, by the complex and costly procedure of a private Act of Parliament.[12] Although the divorce courts set up in the wake of the 1857 Act made the procedure considerably cheaper, divorce remained prohibitively expensive for the poorer members of society.[13][nb 1] An alternative was to obtain a “private separation”, an agreement negotiated between both spouses, embodied in a deed of separation drawn up by a conveyancer. Desertion or elopement was also possible, whereby the wife was forced out of the family home, or the husband simply set up a new home with his mistress.[11] Finally, the less popular notion of wife selling was an alternative but illegitimate method of ending a marriage.”

“Although some 19th-century wives objected, records of 18th-century women resisting their sales are non-existent. With no financial resources, and no skills on which to trade, for many women a sale was the only way out of an unhappy marriage.[17] Indeed the wife is sometimes reported as having insisted on the sale. […] Although the initiative was usually the husband’s, the wife had to agree to the sale. An 1824 report from Manchester says that “after several biddings she [the wife] was knocked down for 5s; but not liking the purchaser, she was put up again for 3s and a quart of ale”.[27] Frequently the wife was already living with her new partner.[28] In one case in 1804 a London shopkeeper found his wife in bed with a stranger to him, who, following an altercation, offered to purchase the wife. The shopkeeper agreed, and in this instance the sale may have been an acceptable method of resolving the situation. However, the sale was sometimes spontaneous, and the wife could find herself the subject of bids from total strangers.[29] In March 1766, a carpenter from Southwark sold his wife “in a fit of conjugal indifference at the alehouse”. Once sober, the man asked his wife to return, and after she refused he hanged himself. A domestic fight might sometimes precede the sale of a wife, but in most recorded cases the intent was to end a marriage in a way that gave it the legitimacy of a divorce.”

“Prices paid for wives varied considerably, from a high of £100 plus £25 each for her two children in a sale of 1865 (equivalent to about £12,500 in 2015)[34] to a low of a glass of ale, or even free. […] According to authors Wade Mansell and Belinda Meteyard, money seems usually to have been a secondary consideration;[4] the more important factor was that the sale was seen by many as legally binding, despite it having no basis in law. […] In Sussex, inns and public houses were a regular venue for wife-selling, and alcohol often formed part of the payment. […] in Ninfield in 1790, a man who swapped his wife at the village inn for half a pint of gin changed his mind and bought her back later.[42] […] Estimates of the frequency of the ritual usually number about 300 between 1780 and 1850, relatively insignificant compared to the instances of desertion, which in the Victorian era numbered in the tens of thousands.[43]

“In 1825 a man named Johnson was charged with “having sung a song in the streets describing the merits of his wife, for the purpose of selling her to the highest bidder at Smithfield.” Such songs were not unique; in about 1842 John Ashton wrote “Sale of a Wife”.[nb 6][58] The arresting officer claimed that the man had gathered a “crowd of all sorts of vagabonds together, who appeared to listen to his ditty, but were in fact, collected to pick pockets.” The defendant, however, replied that he had “not the most distant idea of selling his wife, who was, poor creature, at home with her hungry children, while he was endeavouring to earn a bit of bread for them by the strength of his lungs.” He had also printed copies of the song, and the story of a wife sale, to earn money. Before releasing him, the Lord Mayor, judging the case, cautioned Johnson that the practice could not be allowed, and must not be repeated.[59] In 1833 the sale of a woman was reported at Epping. She was sold for 2s. 6d., with a duty of 6d. Once sober, and placed before the Justices of the Peace, the husband claimed that he had been forced into marriage by the parish authorities, and had “never since lived with her, and that she had lived in open adultery with the man Bradley, by whom she had been purchased”. He was imprisoned for “having deserted his wife”.[60]

v. Bog turtle.

Baby_bog_turtle_in_palm_(cropped)

“The bog turtle (Glyptemys muhlenbergii) is a semiaquatic turtle endemic to the eastern United States. […] It is the smallest North American turtle, measuring about 10 centimeters (4 in) long when fully grown. […] The bog turtle can be found from Vermont in the north, south to Georgia, and west to Ohio. Diurnal and secretive, it spends most of its time buried in mud and – during the winter months – in hibernation. The bog turtle is omnivorous, feeding mainly on small invertebrates.”

“The bog turtle is native only to the eastern United States,[nb 1] congregating in colonies that often consist of fewer than 20 individuals.[23] […] densities can range from 5 to 125 individuals per 0.81 hectares (2.0 acres). […] The bog turtle spends its life almost exclusively in the wetland where it hatched. In its natural environment, it has a maximum lifespan of perhaps 50 years or more,[47] and the average lifespan is 20–30 years.”

“The bog turtle is primarily diurnal, active during the day and sleeping at night. It wakes in the early morning, basks until fully warm, then begins its search for food.[31] It is a seclusive species, making it challenging to observe in its natural habitat.[11] During colder days, the bog turtle will spend much of its time in dense underbrush, underwater, or buried in mud. […] Day-to-day, the bog turtle moves very little, typically basking in the sun and waiting for prey. […] Various studies have found different rates of daily movement in bog turtles, varying from 2.1 to 23 meters (6.9 to 75.5 ft) in males and 1.1 to 18 meters (3.6 to 59.1 ft) in females.”

“Changes to the bog turtle’s habitat have resulted in the disappearance of 80 percent of the colonies that existed 30 years ago.[7] Because of the turtle’s rarity, it is also in danger of illegal collection, often for the worldwide pet trade. […] The bog turtle was listed as critically endangered in the 2011 IUCN Red List.[53]

January 3, 2015 Posted by | Astronomy, Biology, History, Statistics, Wikipedia, Zoology | Leave a comment

A few lectures

 

 

December 14, 2014 Posted by | Astronomy, Lectures, Physics | Leave a comment

Origin and Evolution of Planetary Atmospheres – Implications for Habitability

I recently finished this book. I gave the book two stars on goodreads, however I also added this comment to the information about the book on my 2014 book list: “Close to three stars, but the poor language of the publication made it difficult for me to justify giving it that rating.” I liked reading the book, but I do not condone sloppy and/or unclear language and this is something I’ll usually punish.

When I started reading the book I’d assumed there might be some overlap with Gale’s book, which I haven’t covered here, but that actually turned out not really to be the case; the two books focus on different things even if a few of the questions they ask are quite similar, and so the coverage of the two books actually don’t much overlap. Most of this was new stuff, which was nice. The book is in my opinion more technical and harder to read than was Gale’s book, but again, they deal with different stuff so I’m not sure how much sense it makes to compare them. Lammer doesn’t shy away from covering relevant math formulas where they might be helpful to improve understanding, and/but some of these are not easy to understand if you do not have a background in physics; you need to know some stuff about things like electromagnetism, thermodynamics, and plasma physics to understand all of the stuff in this book. I didn’t – I certainly didn’t know ‘enough’ – but his coverage is fortunately such that even if you mentally skip a few formulas without really understanding the details of the dynamics they model, you’ll usually still be able to figure out roughly how they work wrt. the specific issue at hand because he also talks about how they work and which conclusions to draw; though you’ll likely still need to look up some unfamiliar terms along the way in order not to be completely confused.

I should make clear that although it may sound from the above as if this is really a rather dull book about mathematical formulas and complicated physics, one thing I find it really hard to term this book is ‘boring’. The book talks about what the Earth was like back when Earth was covered by magma oceans. Freaking magma oceans! It talks about how the Earth was quite likely early on in its ‘lifetime’ (before life on the planet, it should perhaps be noted) covered by a huge hydrogen atmosphere, and how that early atmosphere was blown away by a Sun which was spinning much faster than it does today, bombarding the early proto-atmospheres of the newly formed planets with huge numbers of highly charged particles despite the sun shining ‘less brightly’ back then than it does now. It talks about how a slightly different atmospheric composition back then, with more hydrogen, might have lead to the Earth being unable to get rid of all that hydrogen, most likely leading to the Earth having ended up as a ‘waterworld’ without continents, completely covered by water. It talks about how the Sun slowed down after what was most likely just a few million years, and how it has since then been doing things quite differently from the way it did things in the beginning. Phenomena such as outgassing and impact events are discussed. The book talks about how conditions were different on Mars and Venus from the way they were on Earth, and what role various factors might have played in terms of explaining how the atmospheres got to be the way they are now, and why those planets turned out quite different. The role of gravity, the role of a magnetosphere, which concrete processes lead to loss of (/which) atmospheric components. There’s a lot of stuff in this book, and much of it I found really quite interesting. But it is also hard to read, sometimes hard to understand, and certainly far from always particularly well-written. The topics covered I found quite interesting though.

I was wondering how to cover this book, but I decided early on that given how many things I was looking up along the way it would make a lot of sense to bookmark some relevant links and add them to this post; so below I have added a list of terms and concepts covered in the book. Some of the concepts are much better covered in the book than in the links (the wiki article on atmospheric escape for example has very little stuff on this topic compared to the stuff included in the book about this topic), but in other cases there’s a lot of stuff in the wiki article which was not included in the book (naturally, or it would not have made sense for me to look up stuff there). So the stuff in the links don’t add up to the material covered in the book, but the articles should give you a clue what kind of book this is. Below the list I have added a few quotes from the book. As should be obvious from the number of links, the book has a lot of content despite the relatively low page-count.

Atmosphere of Earth.
Troposphere.
Atmospheric escape.
Hydrodynamic escape.
Maxwell–Boltzmann distribution.
Noachian.
Exosphere.
Outflow channels.
Scale height.
Larmor radius.
Adiabatic process.
Energetic neutral atom.
Magnetopause.
Bow shock.
Lyman series.
Heliosphere.
Roche lobe.
Plasma (physics).
Astrophysical plasma.
Photoionization.
Nebular hypothesis.
Stellar evolution.
Protostar.
Protoplanetary disk
.
Solar wind.
Hydrostatic equilibrium.
Kelvin–Helmholtz instability.
Polar wind.

“As contrasted to meteorology which studies the properties and behavior of the lower atmosphere between the surface and the tropopause where the weather phenomena are generated, aeronomy is a division of atmospheric science that studies physics and chemistry of the upper atmosphere that extends from above the troposphere up to the altitudes where it is modified by the solar wind plasma. […] The central part of [this] monograph presents a detailed discussion of the atmospheric loss mechanisms due to the action of various thermal and non-thermal escape processes for the neutral and ionized particles from a hot, extended atmospheric corona. Scenarios for the formation and evolution of the atmospheres of Earth, Venus, and Mars, that is, the planets orbiting within the habitable zone around the Sun, are considered. A crucial role of the magnetosphere of a planet in protecting its hot, extended, and partially ionized corona from the solar wind erosion is discussed. […] The book presents a brief review of the present state of knowledge of the aeronomy of planetary atmospheres and of their evolution during the lifetime of their host stars by taking into account conventionally accepted concepts, as well as recent observational and theoretical results.”

“the classical concept of the habitable zone and its related questions of what makes a planet habitable is much more complex than having a big rocky body located at the right distance from its host star. […] A careful study of various astrophysical and geophysical aspects indicate that Earth-analogue class I habitats have to be located at the right distance of the habitable zone from their host stars, must lose their protoatmospheres during the right time period, should maintain plate tectonics over the planet’s lifetime, should have nitrogen as the main atmospheric species after the stellar activity decreased to moderate values and finally, the planet’s interior should have developed conditions that an intrinsic strong global magnetic field could evolve.” [I should probably add here that this specific stuff is covered extensively in Gale’s book, but doesn’t make up too much of the coverage of this book].

“The mantle solidification of a magma ocean is a fast process and ends at ∼105 years for Earth-size planets with low volatile contents and at ≤3Myr [million years, US] for planets with higher volatile contents and magma ocean depths of ≤2,000km […] During the magma ocean solidification process, H2O and CO2 molecules can enter the solidifying minerals in relative low quantities [8, 9]. As a result the H2O/CO2 volatiles will degas into dense steam atmospheres […] If the early Earth would have obtained slightly more material from water-rich planetesimals, its CO2 content would have been much higher and Earth’s oceans could have been tens to hundreds of kilometers deep […]. Such environmental conditions would have resulted in a globally covered water world [43, 44] which is surrounded by a Venus-type dense CO2 atmosphere and a hydrogen envelope.” [I tried while reading this to imagine a magma ocean which was something like 2000 kilometers deep, but I failed to do so. Just think about this…]

“There is observational evidence from solar proxies with younger age compared to the present Sun, that during the early history of the Solar System the EUV flux was up to∼100 times larger as it is today […] The evolution of planetary atmospheres can only be understood if one considers that the radiation and particle environment of the Sun or a planet’s host star changed during their life time. The magnetic activity of solar-type stars declines steadily during their evolution on the Zero-Age-Main-Sequence (ZAMS). According to the solar standard model, the Sun’s photospheric luminosity was ∼30 % lower ∼4.5 Gyr ago […] when the Sun arrived on the ZAMS compared to present levels. The observed faster rotation of young stars is responsible for an enhanced magnetic activity and related heating processes in the chromosphere, X-ray emissions are ≥1,000, and EUV, and UV ∼100 and ∼10 times higher compared to today’s solar values. Moreover, the production rate of high-energy particles is orders of magnitude higher at young stars, and from observable stellar mass loss-activity relations one can also expect a much stronger solar/stellar wind during the active stellar phase.”

“The nuclear evolution of the Sun is well known from stellar evolutionary theory and backed by helioseismological observations of the internal solar structure [10]. The results of these evolutionary solar models, indicate that the young Sun was ∼10% cooler and ∼15% smaller compared to the modern Sun ∼4.6Gyr ago. According to the solar standard model, due to accelerating nuclear reactions in the Sun’s core, the Sun is a slowly evolving variable G-type star that has undergone an ∼30% increase in luminosity over the past ∼4.5Gyr. […] the outward flowing plasma carries away angular momentum from the star [which explains] the observed spin-down to slower rotation of young stars after their arrival at the ZAMS [the book mentions elsewhere that it’s been estimated based on observations of other star systems that the young sun was rotating more than 10 times as fast as it does now]. […] the early Earth may have lost during [the first 100 million years] an amount of hydrogen equivalent of ∼20EOs [Earth Oceans] thermally […] after the loss of [a large amount of the original steam atmosphere,] the Earth’s atmosphere environment near the surface reached the critical temperature of ∼650 K. After reaching this temperature the remaining H2O-vapor of ∼1EO could condense and collapsed into the liquid water ocean [84]. Additional amount[s] of water could have been delivered also continuously via impacts, but the bulk of the early Earth’s initial water inventory is most likely a by-product of a condensed fraction of the catastrophically outgassed steam atmosphere. […] One should […] note that in the case of the early Earth due to the Moon forming impact a fraction of ≤30% of atmosphere could have also been lost to space [113].”

“The present average atmospheric mass loss of hydrogen, oxygen, and nitrogen ions from the Earth is ∼ 1.3 × 103 g s-1

“The first protoatmosphere will be captured and accumulated hydrogen- and helium-rich gas envelopes from the nebula. Depending on the planetary formation time, the nebula dissipation time, the numbers of additional planets including gas giants in the system, the protoplanet’s gravity, its orbit location, and the host star’s radiation and plasma environment terrestrial planets may capture tens or even several hundreds of the Earth ocean equivalent amounts of hydrogen around its rocky core.
The second protoatmosphere depends on the initial volatile content of the protoplanet when accretion finished. During the magma ocean solidification […] steam atmospheres with surface pressures ranging from∼100 to several 104 bar can be catastrophically outgassed.
Finally, secondary atmospheres will be produced by tectonic activity such as volcanos and by the delivery of volatiles via large impacts. The origin and initial state of a planet’s protoatmosphere, therefore, determines a planet’s atmospheric evolution and finally if the planet will evolve to an Earth-analog class I habitat or not. […] The efficiency of the solar/stellar forcing is essentially inversely proportional to the square of the distance to the planet’s host star. From that, it follows that the closer a planet orbits around its host star, the more efficient are the atmospheric escape processes. The main effects caused by the stellar radiation and plasma environment on the atmospheres of an effected planet are to ionize, chemically modify, heated, expand, and slowly erode the upper atmosphere throughout the lifetime of a planet. The highest thermal and non-thermal atmospheric escape rates are obtained during the early active phase of the planet’s host star […] Besides the orbital location, a planet’s gravity constitutes an additional major protection mechanism especially for thermal escape of its atmosphere, while the nonthermal escape processes are affected on a weaker scale.”

December 11, 2014 Posted by | Astronomy, Books, Geology, Physics | Leave a comment

Wikipedia articles of interest

(A minor note: These days when I’m randomly browsing wikipedia and not just looking up concepts or terms found in the books I read, I’m mostly browsing the featured content on wikipedia. There’s a lot of featured stuff, and on average such articles more interesting than random articles. As a result of this approach, all articles covered in the post below are featured articles. A related consequence of this shift may be that I may cover fewer articles in future wikipedia posts than I have in the past; this post only contains five articles, which I believe is slightly less than usual for these posts – a big reason for this being that it sometimes takes a lot of time to read a featured article.)

i. Woolly mammoth.

Ice_age_fauna_of_northern_Spain_-_Mauricio_Antón

“The woolly mammoth (Mammuthus primigenius) was a species of mammoth, the common name for the extinct elephant genus Mammuthus. The woolly mammoth was one of the last in a line of mammoth species, beginning with Mammuthus subplanifrons in the early Pliocene. M. primigenius diverged from the steppe mammoth, M. trogontherii, about 200,000 years ago in eastern Asia. Its closest extant relative is the Asian elephant. […] The earliest known proboscideans, the clade which contains elephants, existed about 55 million years ago around the Tethys Sea. […] The family Elephantidae existed six million years ago in Africa and includes the modern elephants and the mammoths. Among many now extinct clades, the mastodon is only a distant relative of the mammoths, and part of the separate Mammutidae family, which diverged 25 million years before the mammoths evolved.[12] […] The woolly mammoth coexisted with early humans, who used its bones and tusks for making art, tools, and dwellings, and the species was also hunted for food.[1] It disappeared from its mainland range at the end of the Pleistocene 10,000 years ago, most likely through a combination of climate change, consequent disappearance of its habitat, and hunting by humans, though the significance of these factors is disputed. Isolated populations survived on Wrangel Island until 4,000 years ago, and on St. Paul Island until 6,400 years ago.”

“The appearance and behaviour of this species are among the best studied of any prehistoric animal due to the discovery of frozen carcasses in Siberia and Alaska, as well as skeletons, teeth, stomach contents, dung, and depiction from life in prehistoric cave paintings. […] Fully grown males reached shoulder heights between 2.7 and 3.4 m (9 and 11 ft) and weighed up to 6 tonnes (6.6 short tons). This is almost as large as extant male African elephants, which commonly reach 3–3.4 m (9.8–11.2 ft), and is less than the size of the earlier mammoth species M. meridionalis and M. trogontherii, and the contemporary M. columbi. […] Woolly mammoths had several adaptations to the cold, most noticeably the layer of fur covering all parts of the body. Other adaptations to cold weather include ears that are far smaller than those of modern elephants […] The small ears reduced heat loss and frostbite, and the tail was short for the same reason […] They had a layer of fat up to 10 cm (3.9 in) thick under the skin, which helped to keep them warm. […] The coat consisted of an outer layer of long, coarse “guard hair”, which was 30 cm (12 in) on the upper part of the body, up to 90 cm (35 in) in length on the flanks and underside, and 0.5 mm (0.020 in) in diameter, and a denser inner layer of shorter, slightly curly under-wool, up to 8 cm (3.1 in) long and 0.05 mm (0.0020 in) in diameter. The hairs on the upper leg were up to 38 cm (15 in) long, and those of the feet were 15 cm (5.9 in) long, reaching the toes. The hairs on the head were relatively short, but longer on the underside and the sides of the trunk. The tail was extended by coarse hairs up to 60 cm (24 in) long, which were thicker than the guard hairs. It is likely that the woolly mammoth moulted seasonally, and that the heaviest fur was shed during spring.”

“Woolly mammoths had very long tusks, which were more curved than those of modern elephants. The largest known male tusk is 4.2 m (14 ft) long and weighs 91 kg (201 lb), but 2.4–2.7 m (7.9–8.9 ft) and 45 kg (99 lb) was a more typical size. Female tusks averaged at 1.5–1.8 m (4.9–5.9 ft) and weighed 9 kg (20 lb). About a quarter of the length was inside the sockets. The tusks grew spirally in opposite directions from the base and continued in a curve until the tips pointed towards each other. In this way, most of the weight would have been close to the skull, and there would be less torque than with straight tusks. The tusks were usually asymmetrical and showed considerable variation, with some tusks curving down instead of outwards and some being shorter due to breakage.”

“Woolly mammoths needed a varied diet to support their growth, like modern elephants. An adult of six tonnes would need to eat 180 kg (397 lb) daily, and may have foraged as long as twenty hours every day. […] Woolly mammoths continued growing past adulthood, like other elephants. Unfused limb bones show that males grew until they reached the age of 40, and females grew until they were 25. The frozen calf “Dima” was 90 cm (35 in) tall when it died at the age of 6–12 months. At this age, the second set of molars would be in the process of erupting, and the first set would be worn out at 18 months of age. The third set of molars lasted for ten years, and this process was repeated until the final, sixth set emerged when the animal was 30 years old. A woolly mammoth could probably reach the age of 60, like modern elephants of the same size. By then the last set of molars would be worn out, the animal would be unable to chew and feed, and it would die of starvation.[53]

“The habitat of the woolly mammoth is known as “mammoth steppe” or “tundra steppe”. This environment stretched across northern Asia, many parts of Europe, and the northern part of North America during the last ice age. It was similar to the grassy steppes of modern Russia, but the flora was more diverse, abundant, and grew faster. Grasses, sedges, shrubs, and herbaceous plants were present, and scattered trees were mainly found in southern regions. This habitat was not dominated by ice and snow, as is popularly believed, since these regions are thought to have been high-pressure areas at the time. The habitat of the woolly mammoth also supported other grazing herbivores such as the woolly rhinoceros, wild horses and bison. […] A 2008 study estimated that changes in climate shrank suitable mammoth habitat from 7,700,000 km2 (3,000,000 sq mi) 42,000 years ago to 800,000 km2 (310,000 sq mi) 6,000 years ago.[81][82] Woolly mammoths survived an even greater loss of habitat at the end of the Saale glaciation 125,000 years ago, and it is likely that humans hunted the remaining populations to extinction at the end of the last glacial period.[83][84] […] Several woolly mammoth specimens show evidence of being butchered by humans, which is indicated by breaks, cut-marks, and associated stone tools. It is not known how much prehistoric humans relied on woolly mammoth meat, since there were many other large herbivores available. Many mammoth carcasses may have been scavenged by humans rather than hunted. Some cave paintings show woolly mammoths in structures interpreted as pitfall traps. Few specimens show direct, unambiguous evidence of having been hunted by humans.”

“While frozen woolly mammoth carcasses had been excavated by Europeans as early as 1728, the first fully documented specimen was discovered near the delta of the Lena River in 1799 by Ossip Schumachov, a Siberian hunter.[90] Schumachov let it thaw until he could retrieve the tusks for sale to the ivory trade. [Aargh!] […] The 1901 excavation of the “Berezovka mammoth” is the best documented of the early finds. It was discovered by the Berezovka River, and the Russian authorities financed its excavation. Its head was exposed, and the flesh had been scavenged. The animal still had grass between its teeth and on the tongue, showing that it had died suddenly. […] By 1929, the remains of 34 mammoths with frozen soft tissues (skin, flesh, or organs) had been documented. Only four of them were relatively complete. Since then, about that many more have been found.”

ii. Daniel Lambert.

Daniel Lambert (13 March 1770 – 21 June 1809) was a gaol keeper[n 1] and animal breeder from Leicester, England, famous for his unusually large size. After serving four years as an apprentice at an engraving and die casting works in Birmingham, he returned to Leicester around 1788 and succeeded his father as keeper of Leicester’s gaol. […] At the time of Lambert’s return to Leicester, his weight began to increase steadily, even though he was athletically active and, by his own account, abstained from drinking alcohol and did not eat unusual amounts of food. In 1805, Lambert’s gaol closed. By this time, he weighed 50 stone (700 lb; 318 kg), and had become the heaviest authenticated person up to that point in recorded history. Unemployable and sensitive about his bulk, Lambert became a recluse.

In 1806, poverty forced Lambert to put himself on exhibition to raise money. In April 1806, he took up residence in London, charging spectators to enter his apartments to meet him. Visitors were impressed by his intelligence and personality, and visiting him became highly fashionable. After some months on public display, Lambert grew tired of exhibiting himself, and in September 1806, he returned, wealthy, to Leicester, where he bred sporting dogs and regularly attended sporting events. Between 1806 and 1809, he made a further series of short fundraising tours.

In June 1809, he died suddenly in Stamford. At the time of his death, he weighed 52 stone 11 lb (739 lb; 335 kg), and his coffin required 112 square feet (10.4 m2) of wood. Despite the coffin being built with wheels to allow easy transport, and a sloping approach being dug to the grave, it took 20 men almost half an hour to drag his casket into the trench, in a newly opened burial ground to the rear of St Martin’s Church.”

“Sensitive about his weight, Daniel Lambert refused to allow himself to be weighed, but sometime around 1805, some friends persuaded him to come with them to a cock fight in Loughborough. Once he had squeezed his way into their carriage, the rest of the party drove the carriage onto a large scale and jumped out. After deducting the weight of the (previously weighed) empty carriage, they calculated that Lambert’s weight was now 50 stone (700 lb; 318 kg), and that he had thus overtaken Edward Bright, the 616-pound (279 kg) “Fat Man of Maldon”,[23] as the heaviest authenticated person in recorded history.[20][24]

Despite his shyness, Lambert badly needed to earn money, and saw no alternative to putting himself on display, and charging his spectators.[20] On 4 April 1806, he boarded a specially built carriage and travelled from Leicester[26] to his new home at 53 Piccadilly, then near the western edge of London.[20] For five hours each day, he welcomed visitors into his home, charging each a shilling (about £3.5 as of 2014).[18][25] […] Lambert shared his interests and knowledge of sports, dogs and animal husbandry with London’s middle and upper classes,[27] and it soon became highly fashionable to visit him, or become his friend.[27] Many called repeatedly; one banker made 20 visits, paying the admission fee on each occasion.[17] […] His business venture was immediately successful, drawing around 400 paying visitors per day. […] People would travel long distances to see him (on one occasion, a party of 14 travelled to London from Guernsey),[n 5] and many would spend hours speaking with him on animal breeding.”

“After some months in London, Lambert was visited by Józef Boruwłaski, a 3-foot 3-inch (99 cm) dwarf then in his seventies.[44] Born in 1739 to a poor family in rural Pokuttya,[45] Boruwłaski was generally considered to be the last of Europe’s court dwarfs.[46] He was introduced to the Empress Maria Theresa in 1754,[47] and after a short time residing with deposed Polish king Stanisław Leszczyński,[44] he exhibited himself around Europe, thus becoming a wealthy man.[48] At age 60, he retired to Durham,[49] where he became such a popular figure that the City of Durham paid him to live there[50] and he became one of its most prominent citizens […] The meeting of Lambert and Boruwłaski, the largest and smallest men in the country,[51] was the subject of enormous public interest”

“There was no autopsy, and the cause of Lambert’s death is unknown.[65] While many sources say that he died of a fatty degeneration of the heart or of stress on his heart caused by his bulk, his behaviour in the period leading to his death does not match that of someone suffering from cardiac insufficiency; witnesses agree that on the morning of his death he appeared well, before he became short of breath and collapsed.[65] Bondeson (2006) speculates that the most consistent explanation of his death, given his symptoms and medical history, is that he had a sudden pulmonary embolism.[65]

iii. Geology of the Capitol Reef area.

Waterpocket_Fold_-_Looking_south_from_the_Strike_Valley_Overlook

“The exposed geology of the Capitol Reef area presents a record of mostly Mesozoic-aged sedimentation in an area of North America in and around Capitol Reef National Park, on the Colorado Plateau in southeastern Utah.

Nearly 10,000 feet (3,000 m) of sedimentary strata are found in the Capitol Reef area, representing nearly 200 million years of geologic history of the south-central part of the U.S. state of Utah. These rocks range in age from Permian (as old as 270 million years old) to Cretaceous (as young as 80 million years old.)[1] Rock layers in the area reveal ancient climates as varied as rivers and swamps (Chinle Formation), Sahara-like deserts (Navajo Sandstone), and shallow ocean (Mancos Shale).

The area’s first known sediments were laid down as a shallow sea invaded the land in the Permian. At first sandstone was deposited but limestone followed as the sea deepened. After the sea retreated in the Triassic, streams deposited silt before the area was uplifted and underwent erosion. Conglomerate followed by logs, sand, mud and wind-transported volcanic ash were later added. Mid to Late Triassic time saw increasing aridity, during which vast amounts of sandstone were laid down along with some deposits from slow-moving streams. As another sea started to return it periodically flooded the area and left evaporite deposits. Barrier islands, sand bars and later, tidal flats, contributed sand for sandstone, followed by cobbles for conglomerate and mud for shale. The sea retreated, leaving streams, lakes and swampy plains to become the resting place for sediments. Another sea, the Western Interior Seaway, returned in the Cretaceous and left more sandstone and shale only to disappear in the early Cenozoic.”

“The Laramide orogeny compacted the region from about 70 million to 50 million years ago and in the process created the Rocky Mountains. Many monoclines (a type of gentle upward fold in rock strata) were also formed by the deep compressive forces of the Laramide. One of those monoclines, called the Waterpocket Fold, is the major geographic feature of the park. The 100 mile (160 km) long fold has a north-south alignment with a steeply east-dipping side. The rock layers on the west side of the Waterpocket Fold have been lifted more than 7,000 feet (2,100 m) higher than the layers on the east.[23] Thus older rocks are exposed on the western part of the fold and younger rocks on the eastern part. This particular fold may have been created due to movement along a fault in the Precambrian basement rocks hidden well below any exposed formations. Small earthquakes centered below the fold in 1979 may be from such a fault.[24] […] Ten to fifteen million years ago the entire region was uplifted several thousand feet (well over a kilometer) by the creation of the Colorado Plateaus. This time the uplift was more even, leaving the overall orientation of the formations mostly intact. Most of the erosion that carved today’s landscape occurred after the uplift of the Colorado Plateau with much of the major canyon cutting probably occurring between 1 and 6 million years ago.”

iv. Problem of Apollonius.

“In Euclidean plane geometry, Apollonius’s problem is to construct circles that are tangent to three given circles in a plane (Figure 1).

396px-Apollonius_problem_typical_solution.svg

Apollonius of Perga (ca. 262 BC – ca. 190 BC) posed and solved this famous problem in his work Ἐπαφαί (Epaphaí, “Tangencies”); this work has been lost, but a 4th-century report of his results by Pappus of Alexandria has survived. Three given circles generically have eight different circles that are tangent to them […] and each solution circle encloses or excludes the three given circles in a different way […] The general statement of Apollonius’ problem is to construct one or more circles that are tangent to three given objects in a plane, where an object may be a line, a point or a circle of any size.[1][2][3][4] These objects may be arranged in any way and may cross one another; however, they are usually taken to be distinct, meaning that they do not coincide. Solutions to Apollonius’ problem are sometimes called Apollonius circles, although the term is also used for other types of circles associated with Apollonius. […] A rich repertoire of geometrical and algebraic methods have been developed to solve Apollonius’ problem,[9][10] which has been called “the most famous of all” geometry problems.[3]

v. Globular cluster.

“A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers. The name of this category of star cluster is derived from the Latin globulus—a small sphere. A globular cluster is sometimes known more simply as a globular.

Globular clusters, which are found in the halo of a galaxy, contain considerably more stars and are much older than the less dense galactic, or open clusters, which are found in the disk. Globular clusters are fairly common; there are about 150[2] to 158[3] currently known globular clusters in the Milky Way, with perhaps 10 to 20 more still undiscovered.[4] Large galaxies can have more: Andromeda, for instance, may have as many as 500. […]

Every galaxy of sufficient mass in the Local Group has an associated group of globular clusters, and almost every large galaxy surveyed has been found to possess a system of globular clusters.[8] The Sagittarius Dwarf galaxy and the disputed Canis Major Dwarf galaxy appear to be in the process of donating their associated globular clusters (such as Palomar 12) to the Milky Way.[9] This demonstrates how many of this galaxy’s globular clusters might have been acquired in the past.

Although it appears that globular clusters contain some of the first stars to be produced in the galaxy, their origins and their role in galactic evolution are still unclear.”

October 23, 2014 Posted by | Astronomy, Biology, Ecology, Geography, Geology, History, Mathematics, Paleontology, Wikipedia, Zoology | Leave a comment