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38 Cards in this Set

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  • Back
What was Thales ideas about the make up of the earth?
The earth was a disc or cylinar suported by water. Heavenly vault seperated waters above from waters below. Water was the fundamental substance.
Eratosthenes came up with a way to calculate to size of the earth. How did he acheive this?
He used 2 sticks a different points on the earths surface and measured the angel of the shadows to find out what the size of the angel between the two points. This equation is figured out from simple geometry.
Anaximendar also believed that the earth was like a cylinder. What was the point that was different in his view?
That the earth was an unsupported and was the center of the universe.
What was different about the way that Anaximines percieved the earth and universe?
The earth was a disc supported by air. Air is the fundamental substance. That the stars were attatched by a crystalline sphere.
What did Empedocles propose?
He proposed the doctrine of 4 elements.
What were the 4 elements?
Earth, Water, Air, Fire
What were Anaxagoras' thoughts about the moon?
The moon shines by reflected sunlight. He also thought that the earth and the moon were cylindars.
What were Leucippus Democritus' thoughts on the universe?
He believed the universe was infinite, that there could be other earths and suns.
The followers of Pythagoras came up with ideas about cosmology. What were they?
They thought of the earth as moving. They also thought that at the center of the universe is a central fire. Everything rotated around the central fire.
Heraclides of Pontus had what beliefs of the universe?
The the universe was infinite. That the earth was fixed at the center (of stars) which rotated daily. He aslo said that mercury and venus revolved around the sun.
Aristarchus of Samos believed...?
that the earth revolved around the sun and that the sun is at the center of the stars.
Plato and Socrates contributed what to cosmology?
Pretty much nothing.
What was Eudoxus' contribution to cosmology?
He came up with homocentric spheres, which are a collection of speres with the same center.
How many speres in total did Eudoxus use? And what was each circle used for?
He had 27 in his model. 1 for the stars, 3 for each the sun and the moon, and 4 for each of the 5 planets.
There was one major flaw in Eudoxus' setup what was it?
The flaw was that the distance from the earth always stayed the same for the planets.
What was Aristotle's view of the universe?
He believed that the universe was finite and bounded by the sphere of starts.
What was the 2 sphere frame work?
the 2 shpere frame work extends metaphysically to 2 realms of the universe: 1)earthly realm-out to the lunar shpere, realm of the 4 elements 2)heavenly realm-pure and changing, 5th element quintessance or aether, pure crystalline solid.
What did Aristotle add to Eudoxus' homocentric spheres?
he composed counter rings between the planets. which bumped the amount of circles to 57.
Why did Aristotle believe that the earth and universe have no beginning and no end?
because out of nothing comes nothing.
What did Apollonius of Perga contribute to cosmology?
He came up with 1)eccentric circle 2) deferent and epicycle
What was Ptolemy's explanation for the movement of the planets?
he use the crank mechanism.
What is the crank mechanism?
the center of the epicycle moves around the earth. the crank pushes and pulls the planet in and out from the earth.
What is an equant?
is a point where the motion looks uniform.
How many circles did Ptolemy use?
40 circles
When was Aristotle's works reintroduced into Europe?
In the 12th century.
What is violent motion?
is when an object needs an external agent, requires the continuous action of a force.
Who came up with the idea that there is no wind caused by the earth rotating because the air moves along with the earth?
Nicole Oresme and Jean Buridan
How did Plutarch account for why the moon does not fall into the earth?
"for everything is born in it's own direction wntil changed by another object"
How many circles did Copernicus use?
48 circles.
According to Copernicus what accounts for the motion of the stars?
The apparent motion of the stars is due to a rotating earth.
What is parallax?
Parallax is the angular shift of an object from one point to another. Failure to observe parallax means that the stars are very far away.
what makes it the sun look as though it moves eastward through the stars?
the eastward motion of the earth around the sun accounts for the apparant eastward motion of the sun through the stars.
What occur naturally in Coperancus' plan of the universe?
1) retrograde motion 2) variable brightness 3)variable times for passage through the ecliptic 4)association of mercury and venus with the sun 5) order of the planets.
What is an Astronomical Unit?
it is the average distance between the earth and the sun.
In what year did Tycho Brahe observe a supernova?
What destoyed the idea of the unchanging heavens?
That a nova never moved with the fixed stars.
What did Brahe observe about comets?
That they didn't have a paralax which ment that they are further away than the moon.
What was the Tychonic system?
the earth spun but didn't move, sun and moon moved around the earth, the planets moved around the sun.