Distance
lightyear
It's calculated, not measured. It's the speed of light ... 299,792,458 meters per second ... multiplied by the number of seconds in a standard year.
"Lightyear" is a noun. It is a unit of distance used to measure interstellar space.
Because they are so far away
A unit is what we measure something in. It helps us know both what is being measured, and the scale that is being measured. For example, if the unit is an inch, then we're measuring the length of something relatively small. If the unit is a lightyear, then we're measuring the distance of something huge (most likely the space between things in outer space).
lightyear.
A lightyear is the distance that light can travel in one year.
The distance between stars is typically measured in light years, which represents the distance that light can travel in one year. This unit is used because distances in space are vast and need a large unit of measurement.
a Lightyear, around 1013 kilometres.
Nolume is measured in unit meter cubed, m3.
Force is measured in newton. Gram is a unit of mass, not of force.Force is measured in newton. Gram is a unit of mass, not of force.Force is measured in newton. Gram is a unit of mass, not of force.Force is measured in newton. Gram is a unit of mass, not of force.
The measurement unit depends on the characteristic that is being measured.