ASTRONOMERS

ARISTOTLE

• Was a Greek philosopher.
• His model was where the moon, sun,
• planets, and stars on a series of circles around the earth.
• He thought that if the earth went around the sun,
• then the relative positions of the stars would change as the earth moves.

ARISTARCHUS

• Was a Greek astronomer.
• Had proposed a heliocentric model of the solar system.
• His work was used to solve a scientific problem.
• He attempted to measure relative distances between the sun and moon.

PTOLEMY

• Was an astronomer, geographer, and mathematician.
• His book was based off of observations from 800 years ago.
• Made a model which astronomers used for 14 centuries.

NICOLAUS COPERNICUS

• He thought Ptolemy's model was to complicated.
• He used the wheels on wheels system for his model.
• His model shows that the sun is the center of the solar system.
• His model is seen as the beginning of modern models of the solar system.

JOHANENES KEPLER

• Was a German mathematician and astronomer.
• He figured out that the planets don't orbit the sun in a circle.
• His three laws are planets orbit in ellipses,
• the second one is planets move faster the closer they are to the sun,
• and the third law is how long it takes to orbit the sun for each planet.

GALILEO GALILEI

• He was a scientific theorist.
• He invented new things with a telescope.
• He observed moons orbiting Jupiter.
• His findings were earth is not the only thing that could orbited.

ISAAC NEWTON

• He was a physicist.
• By deriving Kepler's laws of planetary motion from his description of gravity.
• and then using the same principles to account for the trajectories of comets and other phenomena.
• Newton removed the last doubts about the validity of the heliocentric model of the cosmos.

EDWIN HUBBLE

• He was an astronomer.
• He showed that gravity affects the alignment with the orbiting of planets.

END