How many light years is that? 4.21 light years If we hopped aboard our jet, how long would it take us to get to Alpha Centauri C? 40,000,000,000 hours How many years would that take? 4,566,210.0 years Are you packed yet? As an extra challenge, calculate the time it would take to reach Betelgeuse, a red giant located 600 light years away.
The diameter of the Milky Way is about 100,000 light-years and the Sun is located about 28,000 light-years from the Galactic Center. You can see a drawing of the Milky Way below which shows what our Galaxy would look like "face-on" and the direction in which it would spin as viewed from that vantage point.
Our Galaxy is a spiral galaxy that formed approximately 14 billion years ago. Contained in the Milky Way are stars, clouds of dust and gas called nebulae, planets, and asteroids. Stars, dust, and gas fan out from the center of the Galaxy in long spiraling arms. The Milky Way is approximately 100,000 light-years in diameter.
Redshift and Hubble's Law For very far objects (beyond about 1 billion light-years) none of the above methods work. Scientists must move from direct observation to using observations in conjunction with a theory. The theory used to determine these very great distances in the universe is based on the discovery by Edwin Hubble that the universe is expanding.
Galaxies A light-year is the distance light travels in one year. It is 9.5 trillion (9,500,000,000,000) kilometers. The size of a galaxy may be as little as a thousand light-years across or as much as a million light-years across.