Famous AstronomersFamous Astronomers

PtolemyPtolemy

Thought the Earth was at the center of the Thought the Earth was at the center of the universe and that the other planets universe and that the other planets revolved around it (GEOcentric model)revolved around it (GEOcentric model)

Incorrect but predicted the motion of the Incorrect but predicted the motion of the planetsplanets

CopernicusCopernicus

Said the sun was at the center of the Said the sun was at the center of the universe and all planets orbited it universe and all planets orbited it (HELIOcentric model)(HELIOcentric model)

Major changes in science took place after Major changes in science took place after thisthis

Tycho BraheTycho Brahe

Used a mural quadrant to plot the Used a mural quadrant to plot the positions of the stars and moon (helped positions of the stars and moon (helped future astronomers)future astronomers)

Thought the sun and moon revolved Thought the sun and moon revolved around Earth but that all other planets around Earth but that all other planets revolved around the sunrevolved around the sun

Johannes KeplerJohannes Kepler

Using Brahe’s data, he figured out that all Using Brahe’s data, he figured out that all the planets revolve around the sun in an the planets revolve around the sun in an elliptical orbitelliptical orbit

Also found that the sun is not exactly in Also found that the sun is not exactly in the center of those orbitsthe center of those orbits

Developed the three laws of planetary Developed the three laws of planetary motionmotion

GalileoGalileo

First use of telescope to observe spaceFirst use of telescope to observe spaceDiscovered craters and mtns. on the Discovered craters and mtns. on the

moon, sunspots on the sun, and moons of moon, sunspots on the sun, and moons of other planetsother planets

NewtonNewton

Showed that all objects in the universe Showed that all objects in the universe attract each other through gravitational attract each other through gravitational force.force.

The force of gravity depends on the mass The force of gravity depends on the mass of the objects and the distance between of the objects and the distance between them. them.

This explains why the planets orbit the This explains why the planets orbit the most massive object in our solar system: most massive object in our solar system: the sunthe sun

HubbleHubble

Proved that other galaxies existed beyond Proved that other galaxies existed beyond the Milky Way by using a better telescopethe Milky Way by using a better telescope

His data confirmed the beliefs of other His data confirmed the beliefs of other astronomers that the universe is bigger astronomers that the universe is bigger than our solar system.than our solar system.