Ancient Astronomers

Eratosthenes

240 BCE

Eratosthenes discovered the circumference of the earth. This is still used today for several things including GPS, traveling, and much more.

Claudius Ptolemy

150 BCE

Claudius Ptolemy believed that the earth was at the center of the solar system. This was important to astronomy because he had the basics right, that planets are orbiting around something in the solar system, so he gave other astronomers something to work off of.

Nicolaus Copernicus discovered the location of the sun.

1507

Copernicus discovered that the sun is in the center of the solar system. It is important because it has completely changed the way astronomers see the solar system whether it be on a macro or micro level.

Tycho Brahe discovered a new star.

Nov 11, 1572

Tycho Brahe discovered a star in the Cassiopeia formation. Brahe also discovered that comets were objects moving through space and not just objects in the earths atmosphere. He also created several instruments which have paved the way for instruments used in astronomy today.

Johannes Kepler discovers laws of planetary motion.

1609

Kepler discovered the three laws of planetary motion. this is important because it has changed the way we know how our plants orbit the sun. He discovered that the planets orbit is an ellipse and not a perfect circle.

Sir Isaac Newton

1666

Isaac Newton discovered several very important things. He discovered the laws of gravity and motion which astronomers use almost every day, and he also discovered calculus which is also used daily by many and has supported many theories.

Albert Einstein helps formulate gravity and other things.

1905

Albert Einstein found the equivalence of mass and energy, space relativity with the speed of light, and gave astronomers a much better idea of how gravity works. Einstein's discoveries are still used today by astronomers.