5.8 Ancient Astronomers

Timeline created by rbfeltner
  • -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.
  • 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.
  • 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.
  • 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

    Johannes Kepler
    He discovered three laws of planetary motion. This is important because ancient astronomers believed that the earth was the center of the universe, which is incorrect.
  • 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.
  • Albert Einstein

    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.
  • 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.
  • Period:
    100
    to
    170

    Claudius Ptolemy

    He was a Greek mathematician, astronomer, geographer and astrologer. He lived in Alexandria.
  • 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.
  • 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

  • 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.
  • 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.
  • 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.