Question

Distance of stars is measured in:
A. Light years
B. Kilometers per second
C. Kilometers only
D. Nautical miles

Answer 1

Hint: In the above question it is asked that in which unit can be used to measure distance of stars and we also know that the distance of stars is very large so, we require the unit according to that only that’s why we will consider which of the above options given will suffice the answer.

Complete answer:
The distance of stars from the Earth is a very large distance so, we need a different kind of unit to measure that distance.
So, the unit for measuring this much larger distance is the light years.
Let us now discuss what is the light year and how it is used in measuring this much distance in space.
A light-year is defined as the unit with which astronomers measure distance in space. It’s defined by how far a beam of light can travel in one year which is a distance of six trillion miles or is equal to a trillion kilometres. This unit is the same as the inch, the mile, the kilometer, and the furlong but is very large as compared to them.
Let us now think of other options which are given here and why they cannot be the answers.
Kilometers per second are the unit for measuring speed and velocity of the objects, not the distance of the objects. That means it is clearly not the answer
Kilometers is a very small unit when we take the account of the large distances like the distance of the stars so, this cannot be the answer.
Nautical miles is a unit for measuring distance but is used in measuring the distance for ship use not astronomical use that’s why this can also not be the answer.
Hence, we can directly come to the conclusion that option (A) light years is the unit which is used to measure the distance of the stars.

Note: In the above question we got to know light years is the unit used to measure distance of the stars and we can also define light-year as a unit of distance in which a light photon travels in the vacuum in one Julian year. Denoted by ly, and the value of one light-year is constant.