How Do We Measure the Distance Between Stars?

The distances that astronomers deal with when they measure the distance between stars, or between stars and planets, are so great that there would be almost no room on this page to express that distance in miles. Astronomers therefore measure those distances in units called light-years.

A light-year is the distance light travels during one year. Since light travels at the speed of 186,282 miles per second (or 11,176,920 miles per minute), one light-year equals 5.88 million million miles. Written out, it looks like this, 5,880,000,000,000 miles.

Aside from the sun, the nearest star to earth is Alpha Centauri. It is 25 million million miles from earth, or 4.3 light-years away. That means, if life existed on that star and we sent them a message, it would take 8.5 years for that message to get there and be answered.

Some stars in the Milky Way are 80,000 light-years from earth!