How far is a light year?

With all this talk about light years, it may help to truly know how far a light year really is. A light year is an astronomical measure of distance. As defined by the International Astronomical Union, a light year is the distance that light travels in a complete vaccuum in one Julian year, which is about 5,878,630,000,000 miles. So many miles is really hard to comprehend, so to put this into perspective, it is about 3300 miles across the United States from Maine to California. If you traveled back and forth across the country until you went as far as light would travel in a year, you would have to drive coast to coast 1,781,403,030 times! Thats right, almost 2 billion times. In terms of the entire world, which has a circumference of 24,901.55 miles at the equator, you would need to circle the entire planet nearly 236,074,863 times! Our sun is about 93,000,000 miles away from the Earth. If we traveled to the sun and back 31,606 times, we would have finally traveled as far as light does in one year. Now that you know how far a light year is, you can begin to grasp how large our galaxy and the Universe really are.