Ancient Astronomers

Eratosthenes

240 BCE

In 240 BC Eratosthenes calculated the size of the Earth with good accuracy and knew that the shape of the Earth was a sphere. This is important because it was one of the first astronomical discoveries in history.

Claudius Ptolemy

140

Claudius Ptolemy believed that the Earth was the center of the universe. Although this theory was incorrect, it still lead to bigger astronomical discoveries and that is why he is important.

Nicolaus Copernicus

1514

In 1514, Nicolaus Copernicus concluded that we lived in a heliocentric universe instead of a geocentric universe. This means that the Earth and all the other planets orbit around the Sun and not the Earth. This is a very big deal because it changed the way all astronomers viewed space.

Tycho Brahe

1578

Tycho Brache discovered the distance a comet is from earth in 1578. This is important because it also told us that a comets tail is pointed towards the Sun and that comets are farther away from us than the moon.

Johannes Kepler

1600

Johannes Kepler discovered that all planets orbit around the sun in circular motions. This is important because we still use this information today.

Isaac Newton

1680

Isaac Newton built the first working telescope. This is a very big deal because telescopes have helped us make some of the biggest astronomical discoveries. He also discovered the law of universal gravitation.

Albert Einstein

1905

In 1905 Albert Einstein created the mass energy equivalence formula ( E=MC^2 ). This shows how mass can be converted into energy. This is important because it is the most famous formula made.