AST201H1 Study Guide - Final Guide: Laser Guide Star, Spiral Galaxy, Nuclear Fusion

• School: UTSG
• Department: Astronomy & Astrophysics
• Course: AST201H1
• Professor: Michael Reid

Document Summary

Occam"s razor tells us that all other factors being equal, simpler explanations are more likely to be true. The universe is the totality of all space, time, energy and matter. Light travels at a constant, finite speed (c = 300 million m/s) A light year is the distance that light travels in one year (1 ly = 9. 46 trillion km) The universe is about 13. 7 billion years old. There is a limit on the amount of universe we can see because the universe is only 13. 7 billion years old and the light from other places would not have had enough time to travel to us. What we are able to see is called the observable universe. Looking very far away is like looking back in time because the light that we receive with the images has taken lots of time to get to us and the object has changed/aged within that time.