Hey guys,

So I'm studying Cosmology in my school in 9th grade, and I just don't get the concept of light year.

I heard that a light year is "the distance that light travels in a year"

But isn't the speed of light constant? so the distance it travels would always be the same.

If something is 4.2 light years away, what does that mean? Does it mean that it would take light 4.2 years to get there?

Thanks! Help is greatly appreciated!