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If you've done much studying about space, you've probably heard the term 'light year.'
What is a light year?
A light year is the distance that light travels in one Earth year.
Light travels very fast, about 186,000 miles or 300,000 kilometers EVERY SECOND.
Light travels so quickly that even though the earth is 98 million miles or nearly 150
million kilometers from the sun, light from the sun reaches the earth in only 8 minutes
and 20 seconds.
If light can travel that far in minutes, how far can in travel in a year?
One light year equals about 5.8 trillion miles or 9.5 trillion kilometers.
Since space is incredibly huge, using light years makes it easier to talk about distances
outside of our solar system.
The stars nearest to the sun, in the Alpha Centauri system, are more than 4 light years
away, meaning that even something traveling at the speed of light would take more than
4 years to reach them from Earth.