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Period: 276 BCE to 194 BCE
Eratosthenes
He is from Greece. He felt that the Sun was a very far distance from the earth. He wrote a book that is about the constellations and counted the number of stars in each. It is believed that he committed suicide by voluntary starvation and he was blind in his old age. -
240 BCE
Eratosthenes
He is the first to have made a measurement for the size of the Earth. He wasn't entirely accurate but he was within an acceptable range. He did this by comparing the position of the Sun's rays in two locations to calculate the spherical size of the earth. This discovery is important because it shows that the earth is a sphere. -
Period: 100 to 170
Claudius Ptolemy
He was a Greek mathematician, astronomer, geographer and astrologer. He lived in Alexandria. -
150
Claudius Ptolemy
He is known for his world map which was published in the 2nd century and was the first to use longitudinal and latitudinal lines. This was important because he informed other mapmakers the size of the earth and the coordinates of places were featured on his map. -
Period: Feb 19, 1473 to May 24, 1543
Nicolaus Copernicus
He was born in Prussia. He spoke Latin, German, Polish, Greek and Italian and knew some Hebrew. Most of everything he wrote is in Latin. He did not study space with a telescope. Everything was done with the naked eye. His Heliocentric idea was not widely accepted. -
1507
Nicolaus Copernicus
Between 1507 and 1515, he is known for formulating the model of the universe that has the Sun at the center. This is important because it is correct! This had been done by an earlier astronomer, Aristarchus of Samos, eighteen centuries earlier but it is believed that Copernicus did this on his own. -
Period: Dec 14, 1546 to
Tycho Brahe
He was from a noble family. As a result of this, he had a very good education. He took an interest in astronomy and wanted to be able to create instruments that would be more accurate than what was currently available. He was able to figure out that our moon orbited around the earth and that the planets orbited around the Sun. He was incorrect though about the Sun orbiting the earth. Tycho Brahe wanted to have more accurate measurements and dedicated his life to doing this. -
Period: Dec 27, 1571 to
Johannes Kepler
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Period: Dec 27, 1571 to
Johannes Kepler
He was born in Germany. He was an astronomer, mathematician and astrologer. He actually worked with Tycho Brahe. He provided astrological advice to Emperor Rudolph II. -
Nov 11, 1572
Tycho Brahe
On November 11, 1572, Tycho observed a star that had not previously been in the constellation Cassiopeia. He showed that it was a fixed star, that was beyond all the planets. He came up with the word "nova" which means new star. This discovery was important because previous astronomers had implied that anything beyond the moon never changed.
King Frederick II gave Tycho Brahe an island and money to build a research institute. -
Johannes Kepler
He discovered three laws of planetary motion.- The planets move in elliptical orbits with the sun at one focus.
- The time necessary to traverse any arc of planetary orbit is proportional to the are of the sector between the central body
- There is an exact relationship between the squares of the planets' periodic times and the cubes of the radii of their orbits.
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Period: to
Sir Isaac Newton
He was born in England. He was premature and also lost his father three months before he was born. His grandmother raised him. It has been said that every branch of mathematics was advanced because of Newton's work. He did extensive work in calculus. -
Sir Isaac Newton
One of his discoveries was the law of universal gravitation. The importance of this discovery was that not only that objects pull on each other, but that two objects attract each other with a force that is proportional to the square of the distance between them. This is what keeps the universe functioning. The planets revolve around the Sun because of the force of gravity. -
Period: to
Albert Einstein
He was born in Germany. He received the Nobel Prize in Physics for the discovery of Photoelectric Effect, which helped develop Quantum Theory. He is best known for the formula E = mc2 which is the formula for mass-energy equivalence. Albert Einstein was visiting the United States when Adolf Hitler came to power.Because he was Jewish, he did not return to Germany. -
Albert Einstein
In 1905, he developed the Theory of Relativity. This is important because it helps us understand gravity and how it works. It was originally thought that there was an invisible force that attracted objects to each other. Instead, gravity is a warping of space. And the bigger an object, the more it warps the space around it.
