text: how long is a light year?   in one year there are 365 days of 24 hours. each hour has 60 minutes and each minute is 60 seconds long. so, 60s/min x 60min/hr x 24hr/day x 365days equals 31,536,000s. this many seconds is an even larger number than the number of miles light goes in one second! it would take you three years to get to number 31,536,000 if you could write one number per second for eight hours per day. this many miles means you could go back and forth across the united states over one thousand times! at 60 miles per hour it would take you 60 years!   so, we take these two very large numbers and multiply them together to see how many miles light can travel in one year. you can tell already that this is going to be huge! that number is 5,865,696,000,000. working eight hours per day at a rate of one number per second it would take you two hundred thousand years to get to number 5,865,696,000,000! this gets you across the united states two billion times which at our average speed of 60 miles per hour, would take nine trillion years!   now that you know what the distance is that light travels in one year you can also know the distance between objects in the universe. the closest star to us is about four light years away. this means that it is 23,462,784,000,000 miles away. how about this: the edge of the universe is about 15 billion light years away from us! can you even imagine how many miles away that is?