The distance between stars and galaxies in the universe is so vast it would be unwieldy to describe it in miles?like measuring the distance from New York to Tokyo in inches! Instead, scientists use lightyears to measure distances in space. This sounds like a unit of time, but a lightyear is actually a distance: the distance that light travels in one year.
But how far exactly is a lightyear? Light travels 186,000 miles per second. There are 60 seconds in a minute, 60 minutes in an hour, 24 hours in a day, and 365 days in a year. Multiply these together to get 31,500,000 seconds in a year. Multiply that times 186,000 miles per second and you get 5,850,000,000,000 miles?about 6trillionmiles.


The speed of light
If you could drive nonstop to the sun at 60 mph, it would take 180 years. Light makes the same trip in eight minutes. So the sun is about eight lightminutes away.
The distance of a light year
How long would it take the space shuttle to go one lightyear? The shuttle orbits the Earth at about 5 miles per second (18,000 mph). Light travels at 186,000 miles per second, which is about 37,200 times faster than the shuttle. So the shuttle would need about 37,200 years to go one lightyear.

