The universe, our lives, all this stuff – it’s just so incredible it sometimes boggles my mind how we can just walk around, doing whatever it is that we’re doing, just taking all this stuff for granted, overlooking everything. There’s so much to see, to appreciate!
I’ll start here – with a picture of a rock:
It’s not just any rock though – it’s been through a lot. Almost too much to imagine. Allow me to demonstrate what I mean by that…
Now, before going any further I should start by noting that I think that timescales are funny things. I sometimes sort of feel like I don’t really understand them, how they work. I have similar problems with distances now and then, but we’ll get to that later. Of course it’s not that hard to imagine an hour passing by, or a day, or perhaps even a year. But a millenium? I don’t really have a good idea how much time a millenium is – it’s such a long time it boggles the mind. A million years? That’s just crazy. I have no way to conceptualize that kind of time-scale, my mind is much too small for that. So recently I tried to come up with a way to imagine how much time these big multiples of the numbers we usually use to denote time passing by actually represent. I decided to engage in a thought experiment where I’d be counting the years that have gone by and see where I’d end up, starting out where we are now. I pretend I’m able to count one year each second. That way 60 years will go by in just a minute – an entire life of a human being in just a minute. After an hour of counting I’d be close to the starting point of written history; we’d now be 3600 years into the past. We all sort of tell ourselves that we know roughly how long that is; the Jesus stuff is supposed to have happened 2000 years ago, and 3600 years isn’t that different from 2000 after all. But here’s a picture:
This is the Sicilian Temple of Juno Lacinia, and this is what 2400 years – just two thirds of the amount of time we’ve counted so far – looks like from a certain point of view.
Let’s count on: After a day of counting we’d be 86.000 years into the past – so what happened 86.000 years ago? We have little idea, it’s so very long ago. After a year of counting without rest, we’d be 31 million and 536 thousand years into the past – you can count one year each second every second without pause for an entire year of your life and you’re not even half-way to the dinosaurs!
If we assume you count every second of your entire life and you can expect to live 75 years, then the last number you’ll get to is the year that happened 2 billion, 365 million and 200 thousand years ago.
Here’s the kicker: The rock in the image above is much, much older than that.
I’ve been to Copenhagen a few times this year. My parents also went there not too long ago – they came to the city and went back home the same day, for reasons which are not important here. I’ll pretend the trip was 220 kilometres each way; it’s close enough.
200 km is actually a really big distance, once you start thinking about it. We usually don’t, because we have means of transportation that will bring us very fast from A to B. So I decided to think about what would happen if we didn’t have those things; what if they had had to walk to Copenhagen instead of going by car? Well, walking takes more time, but it’s also a lot harder. So I decided to say that it probably wasn’t realistic that they walked more than 12 hours per day, at 5 km/hour. Or 5000 meters per 60 minutes, if you’re of a different persuasion. How long would it have taken them to get back and forth? Well, 5 km/hour and 12 hours per day gives 60 km per day, or 420 km per week. 220 km each way adds up to 440 km in total. So they’d have had to walk for more than a week to get to Copenhagen and back. It would have taken them more than a month to walk to Paris (~900 km) and back.
The closest big thingy you can see at night when you look up into the sky is basically a big rock which reflects the light of a huge ball of fire which luckily is quite a bit farther away from us than the big rock is; a ball of fire which has been burning without stop for a much longer amount of time than you can count years during your life. We like to think the big light-reflecting rock up there is quite near us; some humans have even been up there, so it can’t be that far away, right? Actually it isn’t – from a certain point of view. It’s average distance to Earth is around 385.000 km. If you could ‘fly-walk’ at a very human speed of 5 km/hour, you’d be there in just 17,5 years or so. You could leave at the age of 15 and be back here again at the age of 50. If these kinds of things were possible, which of course they’re not.
Here’s a different way to conceptualize that distance: Let’s think in terms of human-scale magnitudes (one human = ~1,5-2 metres), so that the distance is now 385.000.000 metres, instead of all that cheating with metrics like kilometres. Let’s say an average human is close to 2 metres tall and let’s say we wanted to get up to the moon by standing on top of each other; in order to reach them moon, you’d need something like 200 million people. Let’s do the counting thing again: Count one person per second. It’d take you close to 7 years to count the people you’d need to make that happen. (Of course there are various reasons why that kind of thing wouldn’t work.)
I mentioned that ‘the average distance’ was 385.000. It’s an average because the Moon is moving very fast, just like the Earth, and it doesn’t move around in a perfectly spherical manner. But the Earth and Moon is – as people know these days, although it took a very long time to convince all those well-dressed monkeys that that was how it worked – moving around the Sun as well, and this is where it gets a bit more interesting. The movement around the Sun is, well, fast. The Sun is approximately (such a wonderful word, considering which kinds of distances and differences are actually hidden here) 150 million km away from us. We don’t have enough humans to do the same trick we did with the Moon, not even close. But let’s look a little closer at the speeds involved. The average distance to the Sun is of course not the distance that the Earth travels during a year – the latter number is quite a bit larger, and like many other things it involves the number pi. The Earth goes roughly one billion km/year (940 million km/year, assuming the orbit is circular), which is 108.000 km/hour! Or 30 km each second. It’s almost unbelievable that we don’t notice, that we don’t fall off – that everything just happen the way things do, without anyone sparing much thought as to how utterly insane this is. We don’t even notice.
There’s a lot more on stuff like distances and time frames at Khan Academy. If you want to appreciate just how tiny the distance between the Earth and the Sun really is ‘in the big picture’ but you don’t have the time to watch all those lectures, see also this post.
Now, a different thing you could wonder about is how you can even think the thoughts you’re thinking now. It’s incredibly hard to understand what’s going on there, and we don’t have a very detailed model of the brain as it is. So let’s be less ambitious – let’s just have a look at some of the cells you have hanging around in ‘your body’. Here are a few juxtaglomerular cells, the likes of which are now hanging out in your kidneys (doing useful stuff):
There are a lot of different types of cells in the human body, and the total number of cells in your body is much higher than the number of humans on Earth. So you probably shouldn’t try to count them, like we tried counting other stuff before – you won’t get very far. Obviously they’re not very big, given that we don’t seem to notice them in our day-to-day lives even though there are so many of them. Until a few hundred years ago we didn’t even know such things existed. Now we do, and each day we as a species learn more about the almost infinite number of awesome small living things hanging around everywhere here on Earth. There are so incredibly many of them that cooperate with each other to keep you alive. Even though some of the types of cells in your body live only for a few hours, the combined work of all of them keep ‘you’ going for years, decades. So many things could in theory go wrong – a few cells messing up and dividing the wrong way can end up killing you (yes, I know cancer is more complicated than that – but cancer is nothing special in that respect; things always turn out to be more complicated than you’d think, once you take a closer look..). Depriving the little ones of oxygen for a few minutes will also make many of them get very angry with you, and some of them and their friends ending up the wrong place, one way or the other, may actually quite quickly end the collaborative agreement you’ve had with them for a long time.. Yet somehow things very rarely go wrong, you stay alive, year after year, until one day the little ones have done all they can for ‘you’ and so start worrying more about themselves than about what made you you.
It’s an interesting thing to think about that these small things have been around about as long as the rock in the picture above has, and that you’re a direct descendant of one of those little organisms. If you want a story of how we got from A to B, this is a good book on that topic. If you take a closer look, you’ll also realize that in a very real sense you are those little organisms.
On top of all that… If you look even closer at the cells we talked about, you’ll see that they’re made up of tiny little atoms which are jiggling around all the time, everywhere, at insane speeds and in complex patterns we don’t always understand very well at all. Even though cells are really small, it takes a lot of atoms to make a cell – a lot of atoms which need to constantly ‘cooperate with-‘ and interact with each other to maintain the structure of the cell (and again, if for some reason they don’t cooperate…). We talked about how there were more cells in your body than there are humans on Earth; it turns out that the number of atoms in a cell is roughly the same as the number of cells in a human body – 1014, or 100 trillion. The little atoms get broken down and reassembled in all kinds of ways, all over the place, all the time. I sometimes find it very confusing how all these interactions, all these things can happen everywhere and all the time, right under our noses (and over it, and in it, and…) without us being any the wiser. We look at the world and our eyes interpret the light which is available to us in a manner which the organisms which came before us benefited from. The way our eyes work is part of why we’re alive, why we’re here today – they enabled our ancestors to spot other huge collections of atoms and cells in order to facilitate the most optimal types of interaction with all those other collections of cells and atoms. Oh yes, our eyes are immensely useful things, and if you go into a bit more detail about how they work they’re fascinating things in and of themselves – yes, but even so: Such a profoundly limited, such a coarse-grained view of the world they have given us, compared to what actually is going on!
Or you could talk about the waves, all the different kinds of waves moving around in our environment – sound, heat, light, … Many of them humans can’t even see or feel, and many humans have lived their entire lives without ever knowing they even existed. Just as many people don’t know what that rock at the beginning really looks like when you start to zoom in, and which factors have caused it to look the way it does now, so relatively unharmed by time. I’ve read some stuff about rocks, but I also don’t know that in any amount of detail. And that’s okay – there’s so much stuff to learn you can’t possibly ever get to the bottom of it all.
We’re smart (yet also incredibly stupid), well-dressed apes. Apes which interact with each other and with our environment. If you have a closer look at all that interaction stuff, it turns out that that stuff – all these interaction patterns that form our lives and shape our behaviours – well, that’s just incredibly complex as well.
And it gets worse, or better, depending on whom you ask – because there are trillions of other places out there without smart well-dressed apes; places so remote we can’t even imagine the distances involved, but at the same time also places where we don’t even need to go near to understand a lot of what is happening there. Because we through a combined effort as a species have gotten wonderfully good at understanding what’s going on in this remarkable universe we’re a part of. Ignorance is the default state. But it should not be a desired end state. The world gets so much bigger, so much more interesting, once you start to look closer at what’s going on.
So much stuff to learn, to understand, to appreciate. The world is an amazing place.
I’m sad Feynman died before I ever got to at least have a chance to meet him. He set a good example:
(The last one is a repost, but I love that one. If you like these, see also this abstrusegoose comic.)
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