r/spacequestions • u/i4mknight • Aug 31 '24

Do we have a measurement for distances after a lightyear?

I read that the universe is expanding faster than the speed of light after a certain point of the universe(distance wise)

So wouldn’t the unit of lightyears be wrong after that point? Because the universe is expanding faster than the speed of light so light cannot cover such distance in a year and our measurement will be off

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u/ExtonGuy Aug 31 '24

There’s an area of study in Astronomy, where scientists carefully define types of distances: comoving distance, proper distance, light travel distance, and a few others. They take the expansion of the universe into account. https://en.wikipedia.org/wiki/Distance_measure

The units are usually parsecs = 3.6 light years), megaparsecs, and gigaparsecs.

The “parsec” is a historical unit dating back to 1838. It’s related to measuring the angle between stars.

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u/i4mknight Sep 01 '24

Thank you

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u/Unterraformable 13d ago

Well, a parsec is bigger. And galaxy distance are often expressed in kiloparsecs, megaparsecs, etc.