ASTR 1101 : ASTR 1101 Test 1 Notes
Document Summary
The farther away we look in distance, the further back we look in time. Thus, we see objects as they were in the past: Some galaxy"s (quasars) are millions upon million km away. Ex: orion nebula as it looked 1500 years ago. 2 and half million years our decedents will know what our galaxy will look like right now. Thought question: we can see as far back as physics allows us too. Why can"t we see a galaxy 15 billion light-years away? before the universe existed: because looking 15 billion light-years away means looking to a time, looking to that distance you are looking back in time. Earth is part of the solar system, which is the milky way galaxy, which is a member of the local group of galaxies in the local super cluster. It would take a few thousand years to count the stars.
