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# Why is the distance between stars expressed in light years? What do you understand by the statement that a star is eight light years away from the Earth?

14. Why is the distance between stars expressed in light years? What do you understand by the statement that a star is eight light years away from the Earth?

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Some stars are at such large distances away that the lsrge distances are expressed in another unit known as light year.

So, one light year is equal to distance travelled by the light in one year i.e., (we know the speed of light is about 300,000 km per second) thus,

$1 Light year = 365\times 24\times 60\times 60\times 300,000km$

$= 9,460,800,000,000km$

So, if one light year is equal to 9,460,800,000 metres then,

Eigth light years is equal to  $8\times 9,460,800,000,000km$

i.e., $75,686,400,000,000km$.

So, it means that the star is 75,686,400,000,000 kilometres (8 light years) away from the earth which is much large distance.

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