Astronomers

ARISTOTLE

• He lived from 384 - 322 BCE (62 years)
• Aristotle contributed the idea that the Earth was the center of the solar system (geocentric model).

ARISTARCHUS

• He lived from 310 - 230 BCE (80 years)
• Aristarchus contributed the heliocentric model of the solar system.
• Aristarchus tried to measure the distance between the sun and the moon.

PTOLEMY

• He lived from 90 - 168 AD (78 years)
• Believed in geocentric model
• Observed planets moving backwards, retrograde motion. Circles while doing circles.

NICOLAUS COPERNICUS

• He lived from Feb. 19 1473 - May 24 1543 (70 years)
• Sided with Aristarchus' heliocentric model.
• Circular orbits in model.

JOHANNES KEPLER

• He lived from Dec. 27 1571 - Nov. 15 1630 (59 years)
• Introduced celestial physics
• Created keplerian telescope

GALILEO GALILEI

• He lived from Feb. 15 1564 - Jan. 8 1642 (77 years)
• Believer of Heliocentrism.
• Telescopic confirmation of the phases of Jupiter.
• Observation and analysis of sunpots.

ISAAC NEWTON

• He lived from Dec. 25 1642 - Mar. 20 1727 (46 years)
• Introduced gravity and the laws of motion.
• Created first reflecting telescope.

EDWIN HUBBLE

• He lived from Nov. 20 1889 - Sep. 28 1953 (63 years)
• Created Hubble Telescope.
• Supported the Doppler shift.
• Created Hubble's law.

GEOCENTRIC MODEL

• The first model of the solar system that places Earth at the center.
• Proposed first by Aristotle

HELIOCENTRIC MODEL

• The second model of the solar system that places the Sun at the center.
• Proposed first by Aristarchus