light year

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light year

a unit of distance used in astronomy, equal to the distance travelled by light in one year, i.e. 9.4607 × 1012 kilometres or 0.3066 parsecs

light year

The distance light travels in one year, which is approximately 5.9 quadrillion miles. Abbreviated "ly," light years are used to measure distances in the universe. For example, the galaxy is presumed to be about 100 ly across. Proxima Centauri, at about 4.22 ly from the sun, is the closest star to the sun.

It's About Distance, Not Time
Because the word "year" is used, light years are often erroneously used to measure time. The phrase "I spent light years doing that" might sound triumphant, but it is like saying "I spent a million miles doing that."
References in periodicals archive ?
But these dust clouds are actually other galaxies millions of light years away.
We've reduced our galaxy, 100,000 light years in diameter, first to 170 miles, and now to the size of a plate you could hold in your hand.
Others said it showed independence was light years away.
One light year is an amazing 5,878,499,814,000 miles - so the probabilities of photographing another Scotland so far away is truly mind-boggling.
The telescope was focused on Capella, a binary star some 40 light years away.
Using straightforward geometry, they then determined that the supernova lies 169,000 light years from Earth.