So, how long is a light year...short answer: Long!!! long answer: about 5.9 trillion miles!!! That's how quickly light can traverse across space. So if you wanted to walk the distance of a light year you would need to be marching on your feet for about 168 million years!! For you to arrive at this moment, you would have had to start walking from the time when dinosaurs ruled the earth! Whew...better pack a few lunches for the calories you would have been using up! The speed at which light travels is still the fastest known speed in our universe.
On a related note, there sure are a lot of movies that make reference to this amazingly fast speed. Warp speed, Hyperspace, and Ludicrous speed are all references to the fastest known speed that we humans have been able to identify!
Check out more info on light year and big stellar distances here: Distance!
Also, Cool Cosmos has some pretty cool info about some of these huge distances and times!