AST101H1 Lecture 1: Lecture 1/Chapter 1

• School: UTSG
• Department: Astronomy & Astrophysics
• Course: AST101H1
• Professor: Bryan Gaensler

Document Summary

Solar system - the sun, the planets, and all of their moons. Which pair of objects do you think are most different from one another in relative size? the observable person and a person. 1 au = 1 astronomical unit = 1. 5x10^11m = average distance between earth and sun. 1 ly = 1 light year = 9. 46x10^12 km = about 63,000 au = distance light travels in one year. Stars are balls of plasma which produce energy by nuclear fusion. 1. planets orbits starts directly (not other planets) 2. planets must be massive enough for their own gravity to compress them into spherical shapes. 3. parent start in orbits very similar to the planet. Ceres orbits the sun in the asteroid belt between mars and jupiter. it is large enough to be spherical. ceres is a dwarf planet. Objects which fail the definition of a planet on the last criterion are called dwarf planets.