observing the solar system
DESCRIPTION
Observing the Solar System. Section 20.1. Early Observations. Greek Observations Saw star patterns in the sky travel together (Constellations). Early Observations. Some stars seemed to wander (planets) They were later named by the Romans (Mercury, Venus, Mars, Jupiter, Saturn). - PowerPoint PPT PresentationTRANSCRIPT
Early Observations
Greek Observations
• Saw star patterns in the sky travel together
(Constellations)
Early Observations
• Some stars seemed to wander (planets)
• They were later named by the Romans(Mercury, Venus, Mars, Jupiter, Saturn)
Early Observations
• Most Greek astronomers believed that Earth was in the center of a celestial sphere. (geocentric system)
Early Observations
Claudius Ptolemy
• Earth in center• Planets move on small circle that move on bigger circles• Widely accepted for 1500 years
Early ObservationsNicholas Copernicus• Believed in a sun centered
system (Heliocentric)
• Said the planets moved around the sun in circles in 1543
Mikolaj Kopernik
Early ObservationsNicholas Copernicus• He was banned by the
Catholic church
• Galileo used the telescope to support him (Venus phases, Jupiter’s moons)
• He was placed under house arrest
Mikolaj Kopernik
Galileo
Early Observations
Johannes Kepler
• Analyzed Brahe’s observations and found that the path of the orbits were ellipses
• Kepler’s 1st Law
Early Observations
Johannes Kepler
• He found that the speed of orbiting planets is constantly changing
• Kepler’s 2nd Law
Early ObservationsJohannes Kepler• When he compared
planets, he found a relationship between how far from the sun they were and the time to make one orbit
• Kepler’s 3rd Law
Early Observations
Today we know of 8 planets (MVEMJSUN) their moons, and smaller objects that revolve around the sun
What about Pluto?
• According to the new definition, a full-fledged planet is an object that orbits the sun and is large enough to have become round due to the force of its own gravity. In addition, a planet has to dominate the neighborhood around its orbit.
• Pluto does not dominate its neighborhood
Charon is half it size
It does not sweep up its neighborhood, there is
much debris in its orbit