AST101H1 Lecture Notes - Lecture 2: Local Group

• School: UTSG
• Department: Astronomy & Astrophysics
• Course: AST101H1
• Professor: Michael Reid

Document Summary

State the full cosmic address of earth. Correctly use the terms planet, dwarf planet, etc Earth < sol system < milky way galaxy < local group < universe: our planet < our solar system < many solar systems orbiting a common centre < A group of galaxies close to each other < everything in existence. However big you imagine space to be, you are wrong: jupiter is about 10 times the size of earth, the sun is about 10 times the size of. The solar system is huge and the vast majority of it is empty : empty as in filled with tiny particles of gas and dust. 1 au = 1 astronomical unit = 150 000 000km = average distance between sun and earth. Closest star is alpha centauri, 4. 4 light years away. Jupiter is 5 au from the sun: 1 ly = 1 light year = about 63 000 au = distance light travels in one year.