Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Exploration of Jupiter wikipedia , lookup
Planet Nine wikipedia , lookup
Late Heavy Bombardment wikipedia , lookup
Exploration of Io wikipedia , lookup
Planets beyond Neptune wikipedia , lookup
Dwarf planet wikipedia , lookup
History of Solar System formation and evolution hypotheses wikipedia , lookup
Formation and evolution of the Solar System wikipedia , lookup
Definition of planet wikipedia , lookup
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) 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 Observations Nicholas Copernicus • Believed in a sun centered system (Heliocentric) Mikolaj Kopernik • Said the planets moved around the sun in circles in 1543 Early Observations Nicholas Copernicus • Was banned by the Catholic church Mikolaj Kopernik Galileo • Used the telescope to support him (Venus phases, Jupiter’s moons) • Was placed under house arrest Galileo Early Observations Tycho Brahe • Made accurate observation for over 20 years 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 Observations Johannes 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