ASTRONOMERS

ARISTOTLE

• Aristotle lived 384- 322 BC
• he also found out that earth was a sphere
• said that earth was the center of the universe

ARISTARCHUS

• 310-230 B.C
• Aristarchus found that Earth rotates on its axis and revolves around the sun
• and said that the sun is the centered

Ptolemy

• 100 —170 AD
• Ptolemy said earth is at the center of the universe
• explained the retrograde motion of planets

NICOLAUS COPERNICUS

• 1473–1543
• Nicolaus said that the sun is the center of the unerverss
• used circular orbits

Johanenes Kepler

• 1571-1630
• planets orbits around an off-centre sun

Galileo Galilei

• 1564-1642
• Galileo was the first to see craters on the moon, find sunspots, and track the movemet of Venus

ISAAC NEWTON

• 1642-1727
• Isaac found out why plaint orbit

EDWIN HUBBLE

• 1889-1953
• Edwin showed how the universe is growing

GEOCENTRIC SOLAR SYSTEM

• Earth and other planets orbit around the earth

HELIOCENTRIC

• the sun is the center of the universe