PCS 581 Study Guide - Comprehensive Final Exam Guide - Sun, Orbit, Gravity
Document Summary
We live in a big, mysterious universe. Humanity has found a way to figure out the rules: the scientific method: scientific method is a way of problem solving. We want to describe the things we observe. We want to explain and understand those things. We must appreciate our place in the universe, and our ability to discover, explore and learn. The andromeda galaxy is 2. 5 million light-years from us. 2. 5 billion years ago light takes 2. 5 years to travel to earth. Light is a natural time machine into our past. The farther away it is the longer it takes light to reach us. The farther away we look, the farther back we are looking in time. Age of the universe: 13. 7 billion years ago. Observe using light, which travels at 300,000 km/s. Yes: we can look back 14 billion light years into the past it is just how far we can see.
