Astr 205 exam study guide - Study guides, Class notes & Summaries

Scientific notation is used in science because - it makes it easy to write big or small numbers. The average distance from Earth to the sun is - 1 AU The sun is - a star 1 AU from Earth. more than 100 times the diameter of Earth. A galaxy contains - gas, dust, and stars, and a lot of dark matter. The Milky Way Galaxy - contains about 100 billion stars. 2.9×107 is the same as - . 29 million It takes light 1.3 seconds to travel from the moon to Earth and 8 minutes to travel from the s...