Econstudentlog

Wikipedia articles of interest

i. Golden Eagle.

642px-Golden_Eagle_in_flight_-_5

I checked out the wiki article after I’d come across this article with some amazing pictures (“While the three photos were taken over the course of just two seconds, they made scientific history.”).

“The Golden Eagle (Aquila chrysaetos) is one of the best-known birds of prey in the Northern Hemisphere. It is the most widely distributed species of eagle. Like all eagles, it belongs to the family Accipitridae. These birds are dark brown, with lighter golden-brown plumage on their napes. Immature eagles of this species typically have white on the tail and often have white markings on the wings. Golden Eagles use their agility and speed combined with extremely powerful feet and massive, sharp talons to snatch up a variety of prey (mainly hares, rabbits, marmots and other ground squirrels).[2] […]

Golden Eagles are sometimes considered the most superlative fliers among eagles and perhaps among all raptorial birds.[23] They are equipped with broad, long wings with somewhat finger-like indentations on the tips of the wing.[5] Golden Eagles are unique among their genus in that they often fly in a slight dihedral, which means the wings are often held in a slight, upturned V.[5] When they must engage in flapping flight, Golden Eagles appear at their most labored but this flight method is generally less common than soaring or gliding flights.[2] Flapping flight usually consists of 6–8 deep wing-beats, interspersed with 2 to 3 second glides.[2] While soaring the wings and tail are held in one plane with the primary tips often spread.[25] A typical, unhurried soaring speed in Golden Eagles is around 45–52 kilometers per hour (28–32 mph).[26] When hunting or displaying, the Golden Eagle is capable of very fast gliding, attaining speeds of up to 190 km/h (120 mph).[2][25] When diving (or stooping) in the direction of prey or during territorial displays, the eagle holds its wings tight and partially closed against their body and the legs up against tail. In a full stoop, a Golden Eagle can reach spectacular speeds of up to 240 to 320 kilometers per hour (150 to 200 mph) when diving after prey. Although less agile and maneuverable, the Golden Eagle is apparently quite the equal and possibly even the superior of the Peregrine Falcon’s stooping and gliding speeds.[3][27] This places the Golden Eagle as the one of the two fastest moving living animals on earth.[9] [Note though that: “The Peregrine is renowned for its speed, reaching over 322 km/h (200 mph) during its characteristic hunting stoop (high speed dive),[6] making it the fastest member of the animal kingdom.[7][8] According to a National Geographic TV programme, the highest measured speed of a Peregrine Falcon is 389 km/h (242 mph).[9][10]” – from the (featured) wikipedia article about the Peregrine Falcon]. […]

One of the most fascinating, though relatively little studied, aspects of the Golden Eagle’s biology is how it interacts with other predators in a natural environment, especially other large predatory birds. The Golden Eagle is a powerful hunter with few avian rivals in size or strength, although what it gains in these areas it loses somewhat in its agility and speed. Golden Eagles are avian apex predators, meaning a healthy adult is not generally preyed upon. There are several other large birds of prey that inhabit the Northern Hemisphere that may be attracted to the same prey, habitats and nesting sites as the Golden Eagles. Two examples are the Common Raven and Peregrine Falcon (Falco peregrinus) as these are two fairly large-bodied, mostly predatory birds that co-exist with Golden Eagles in almost every part of their range, although the former occurs in much larger numbers and the latter has a much larger natural distribution in more varied habitats. Both the Raven and the Peregrine are often attracted to much the same precipitous habitat as the Golden Eagle. However, both are generally dominated by the much larger eagle and will actively avoid nesting in the same area as a Golden Eagle pair.[198][199][200]

It’s a very long article, so there’s a lot of stuff there if you’re curious to learn more.

ii. Triton (moon) (featured).

600px-Triton_moon_mosaic_Voyager_2_(large)

Triton is the largest moon of the planet Neptune, discovered on October 10, 1846, by English astronomer William Lassell. It is the only large moon in the Solar System with a retrograde orbit, which is an orbit in the opposite direction to its planet’s rotation. At 2,700 kilometres (1,700 mi) in diameter, it is the seventh-largest moon in the Solar System. Because of its retrograde orbit and composition similar to Pluto‘s, Triton is thought to have been captured from the Kuiper belt.[10] Triton has a surface of mostly frozen nitrogen, a mostly water ice crust,[11] an icy mantle and a substantial core of rock and metal.[5] The core makes up two-thirds of its total mass. Triton has a mean density of 2.061 grams per cubic centimetre (0.0745 lb/cu in)[4] and is composed of approximately 15–35% water ice.[5]

Triton is one of the few moons in the Solar System known to be geologically active. As a consequence, its surface is relatively young, with a complex geological history revealed in intricate and mysterious cryovolcanic and tectonic terrains.[5] Part of its crust is dotted with geysers thought to erupt nitrogen.[9] […]

Triton’s revolution around Neptune has become a nearly perfect circle with an eccentricity of almost zero. Viscoelastic damping from tides alone is not thought to be capable of circularizing Triton’s orbit in the time since the origin of the system, and gas drag from a prograde debris disc is likely to have played a substantial role.[2][3] Tidal interactions also cause Triton’s orbit, already closer to Neptune than the Moon’s to Earth, to slowly decay further; predictions are that some 3.6 billion years from now, Triton will pass within Neptune’s Roche limit.[20] This will result in either a collision with Neptune’s atmosphere or the breakup of Triton, forming a ring system similar to that found around Saturn.[20] […]

iii. Myth of the Flat Earth.

“The myth of the Flat Earth is the modern misconception that the prevailing cosmological view during the Middle Ages saw the Earth as flat, instead of spherical.[1] The idea seems to have been widespread during the first half of the 20th century, so that the Members of the Historical Association in 1945 stated that:

The idea that educated men at the time of Columbus believed that the earth was flat, and that this belief was one of the obstacles to be overcome by Columbus before he could get his project sanctioned, remains one of the hardiest errors in teaching.[2]

During the early Middle Ages, virtually all scholars maintained the spherical viewpoint first expressed by the Ancient Greeks. From at least the 14th century, belief in a flat Earth among the educated was almost nonexistent, despite fanciful depictions in art, such as the exterior of Hieronymus Bosch‘s famous triptych The Garden of Earthly Delights, in which a disc-shaped Earth is shown floating inside a transparent sphere.[3] […]

Since the early 20th century, a number of books and articles have documented the flat earth error as one of a number of widespread misconceptions in popular views of the Middle Ages. Both E.M.W. Tillyard’s book The Elizabethan World Picture and C.S. Lewis’ The Discarded Image are devoted to a broad survey of how the universe was viewed in Renaissance and medieval times, and both extensively discuss how the educated classes knew the world was round. […] Although the misconception was frequently refuted in historical scholarship since at least 1920, it persisted in popular culture and in some school textbooks into the 1960s.”

iv. Tanks of the interwar period.

This is what a tank looked like in 1918 (…’A’):

Allied_Mark_VIII_(Liberty)_Tank

And here’s how a tank looked like 21 years later (…’B’):

Polen, Panzer III mit Panzersoldaten
The article will tell you something about how they got from ‘A’ to ‘B’.

v. Golden Horde.

The Golden Horde (Tatar: Алтын Урда Altın Urda; Mongolian: Зүчийн улс, Züchii-in Uls; Russian: Золотая Орда, tr. Zolotaya Orda) was a Mongol and later Turkicized khanate, established in the 13th century, which comprised the northwestern sector of the Mongol Empire.[1] The khanate is also known as the Kipchak Khanate or as the Ulus of Jochi.[2]

After the death of Batu Khan in 1255, the prosperity of his dynasty lasted for a full century, until 1359, though the intrigues of Nogai did instigate a partial civil war in the late 1290s. The Horde’s military power peaked during the reign of Uzbeg (1312–41), who adopted Islam. The territory of the Golden Horde at its peak included most of Eastern Europe from the Urals to the right bank of the Danube River, extending east deep into Siberia. In the south, the Golden Horde’s lands bordered on the Black Sea, the Caucasus Mountains, and the territories of the Mongol dynasty known as the Ilkhanate.[3]

The khanate experienced violent internal political disorder beginning in 1359, before it was briefly reunited under Tokhtamysh in 1381. However, soon after the 1396 invasion of Tamerlane, it broke into smaller Tatar khanates that declined steadily in power. At the start of the 15th century the Horde began to fall apart. By 1433 it was being referred to simply as the Great Horde. Within its territories there emerged numerous, predominantly Turkic-speaking, khanates. These internal struggles allowed the northern vassal state of Muscovy to rid itself of the “Tatar Yoke” at the Great stand on the Ugra river in 1480. The Crimean Khanate and the Kazakh Khanate, the last remnants of the Golden Horde, persisted until 1783 and 1847, respectively. […]

After Uzbeg (Öz-Beg) mounted the throne in 1313, he adopted Islam as the state religion. He proscribed Buddhism and Shamanism among the Mongols in Russia, thus reversing the spread of the Yuan culture. By 1315, Uzbeg had successfully Islamicized the Horde, killing Jochid princes and Buddhist lamas who opposed his religious policy and succession of the throne.

Mohammed Uzbeg Khan continued the alliance with the Mamluks which Berke and his predecessors had begun. He kept a friendly relationship with the Mamluk Sultan and his shadow Caliph in Cairo. After a long delay and much discussion, he married a princess of the blood to Al-Nasir Muhammad, Sultan of Egypt.

The Mongol rulers’ Rus’ policy was one of constantly switching alliances in an attempt to keep Russia and Eastern Europe weak and divided. […]

Uzbeg, whose total army exceeded 300,000, repeatedly raided Thrace, partly in service of Bulgaria’s war against both Byzantium and Serbia from 1319 on. The Byzantine Empire, beginning in the reign of Andronikos II Palaiologos and continuing in that of Andronikos III Palaiologos, was raided by the Golden Horde between 1320 and 1341, until the Byzantine port of Vicina Macaria was occupied. Some sources report that Uzbeg also married Andronikos III’s illegitimate daughter, who had taken the name Bayalun, and who later, after relations between the Horde and the Byzantines deteriorated, fled back to the Byzantine Empire, apparently fearing her forced conversion to Islam.[55][56] His armies pillaged Thrace for forty days in 1324 and for fifteen days in 1337,taking 300,000 captives. However, his attempt to reassert Mongol control over Serbia was unsuccessful in 1330.[57]

(The article has much more.)

vi. Caesium (featured).

October 13, 2013 - Posted by | astronomy, biology, history, wikipedia

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