0
Actually, "astronauts" usually don't. They measure distances mostly in km. The furthest from Earth any astronaut has ever been is about 400,000 km, which is still a manageable number in km.
Astronomers don't either, for the most part; they tend to use either AU (for in-system distances) or parsecs for interstellar distances.
When light-years are used, it's generally because the distances involved are too large for km or AU. 1 light year is about 9,500,000,000,000 km, so you can see how much of a difference that makes. 1 light year is only about 63,200 AU, but that still adds up pretty quickly.
What else can I help you with?
What do light years measure in astronomy?
Light years measure distance in astronomy. It is the distance that light travels in one year, which is about 9.46 trillion kilometers.
If you are four years away from a place would you be 4 light years away?
No, 'years' is a measure of time and 'light years' is a measure of distance.
How many years are in twenty light years?
Zero. Light years are a measure of distance, not time.
What unit of measure is used to measure the distance to the stars?
light years
How many years is 587 light years?
Light years is a measure for distance, the distance light travels in one year. For the light to travel 587 light years, it takes 587 years.
How many light years are equal to 4.5 billion years?
A light year is a measure of distance, not time. It is the distance light travels in a year.
How many years in an one light years?
None. A light year is a measure of distance, not of time.
What unit of distance used to measure items in space?
Light years: the distance that light travels in a year.
What do astromoners measure distance in between stars with?
light years
What unit would you use to measure the distances from stars?
To measure the distance of stars you have to measure by light years.
4.3light year is equais to how many earth years?
In spite of its name, a light year does not indicate time, but it indicates distance! It actually equates to the distance that light travels in one Earth year, which is a very big distance, seeing that light travels at 186,000 miles per second.
When should you use light years?
Light years are used to measure distance from Earth to distant stars and planets.
