History of Astronomy Ch

Early Civilizations Greeks, Romans, Egyptians, and Chinese – All had some general interpretations of the Universe – Played a large factor in Religious Beliefs

Chinese 1400 BC- Present Created constellations based upon mythical animals Constellations- an internationally defined area of the celestial sphere Used stars to track time Kept detailed records of the heavens – Recorded a Supernova in 1054 Lit up the sky day and night for weeks

Chinese Star Map

Chinese Constellations

Greek/Romans 400 BC- 300 AD Named the planets after their gods Defined European Constellations First groups to try and learn our place in the Universe

Greco-Roman Constellations

Mayans (1000 AD) Used astronomy to predict future Created astronomical calendars – Very precise understanding of time through the tracking of the stars

Temples Designed Around Astronomy

Greeks First true astronomers Had actual models of the Universe – Only the solar system Sun, Moon, Earth, Mercury, Mars, Venus, Jupiter and Saturn

Plato Aristotle

Aristotle (384 – 322 BC) Had a geocentric view of the universe – Geocentric- thought that the Earth was the center of the universe Believed that the universe was governed by geometry – Specifically, all heavenly bodies moved in the perfect shape….the circle

Aristarchus (310 – 230 BC) Disagreed with geocentrism – Argued in favor of heliocentrism Heliocentric- the sun is the center of the universe Problems with Heliocentrism 1.Doesn’t feel like we are moving Wouldn’t there be a strong wind? 2.Doesn’t look like we’re moving Why don’t things change distance?

Ptolemy ( AD) Developed the first full model of the universe – Used geocentric model – All objects existed in spheres around the Earth

Orbit of Mars (Problem)

Epicycle- Mini-circular orbits as a part of a larger deferent Deferent- The larger circular orbit of astronomical bodies

Nicholas Copernicus ( ) Brought back Heliocentrism – Still believed in circular orbits – Also tried to explain odd circles in each orbit – Public and scholars did not believe him All books were written in Latin No one read Latin

Johannes Kepler ( ) Felt that circles were nice, but incorrect Proposed elliptical orbits – 3 Laws of Planetary Motion 1.Planetary orbits are elliptical 2.Objects move faster when closer to a large object 3.Speed of orbit changes with the size of the orbit

Galileo Galilei ( ) Clarified Copernicus’ ideas First to use the telescope to study astronomy – Banned by church for his writings

Phases of Venus Craters on the Moon Galilean MoonsSun Spots

Isaac Newton ( ) Established three laws of motion Helped to establish orbit rules through math First person to propose gravitational force Created first reflecting telescope – Clearer than lens based telescope