AST101H1 Lecture Notes - Solar System

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

Document Summary

4. 6 billion years ago, gas and dust came together to form planets. 4. 52 billion years ago, something hit the earth which created the moon, then something formed a ring around the earth and is now the sun. 4. 3 billion years ago it was molten and was not a livable environment. 3. 5 billion years ago when the liquid solidified bacteria formed. 3. 0 billion years ago they became much more complicated. 65 million years ago a huge rock smacked into yucatan peninsula and made. Galaxy: collection of several hundred billion stars. Hence, 1 light-year is about 10 ^13 km (=10 trillion = 10,000,000,000,000) (similarly for light-second, light-hour )