CAS AS 102 Lecture Notes - Scientific Method, Celestial Equator, Cosmological Principle
20 Jan 2014
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Document Summary
Milky way is part of a group of galaxies called the local group. 1 astronomical unit (au) is the distance from the sun to the earth. Light is the fastest thing that moves. Light travels at 300000 km= 670,616,629 mph every second. Light would travel are the earth in 1/7 of a second. In 1. 25 second, light travels from earth to the moon. Voyager spacecrafts move at 3 au a year. The distance from earth to the closest star is 4 years. For us to get to the cloest galaxy to us, andromeda, it would take 3. 5 million years. The age of the universe is 13. 7 billion years, so any light farther than that hasnt had time. Observable universal is our universe that is 13. 6 billion years old, the stuff that we can to arrive to us yet see. Except for hydrogen, all of the atoms in our body were made in stars.
