“Light years measure distance, not time. Light can be slowed down and can be sped up” – @joecienkoski, 31/10/2010 @ 15:51

Let’s look at the definition of light year shall we.

A light-year is the distance that light travels in a vacuum in one Julian year, about 6 trillion miles.

So light year is a unit of distance but, and I know this is hard to follow for creationists, there is a clue about the TIME it takes light to travel in a light YEAR. Can you spot it?

Now Joey is perfectly right, light has been slowed down and sped up in laboratories BUT that’s irrelevant since a light year is light in a “vacuum” not a laboratory.