Whos Who of Early Astronomy Timeline 1 Ptolemy

Who’s Who of Early Astronomy

Timeline 1 Ptolemy 100 -170 AD • Observed motion of planets • Developed the geocentric model of solar system • Accepted for 1, 500 years.

Geocentric = Earth is center of solar system/universe

Geocentric=Earth is at the center of revolving planets and stars Draw a diagram of the geocentric solar system and label it

Copernicus 1473 -1543 • Proposed heliocentric model of the solar system • Not everyone accepted this theory

Heliocentric = Sun is center of solar system

Heliocentric=Earth and other planets revolve around the sun Diagram heliocentric solar system and label it.

Tycho Brahe 1546 -1601 • Tracked planetary motion through careful observation for 20 years. • Careful experiment vs. philosophical arguments.

Kepler 1571 -1630 • Used Brahe’s data to develop three laws of planetary motion.

Galileo 1564 -1642 • Used newly developed telescope to gather evidence that supported the heliocentric model.

Newton 1642 -1727 Explained the force that keeps planets in orbit They are the same forces that work here on Earth! A universal force!

Hubble 1889 -1953 • He was the first astronomer to find observable evidence that the universe is expanding • His discovery helped establish the “Big Bang Theory. ” • Use detailed observations to prove that other galaxies existed beyond the edge of our galaxy the Milky Way. • His data confirmed that the universe is much larger than our own galaxy, the Milky Way.

Lemaître 1894 -1966 • Created Big Bang Theory • He figured that if you traced the idea of the universe back in time, all the way to the very beginning, everything had to converge into a single point. • Lemaître called that point a superatom. • He suggested that the expansion of the universe had resulted from the explosion of this superatom that hurled materials in all directions, and set the universe as we know it in motion.

Bondi 1919 -2005 Created Steady State Theory