How Fast Can Light Travel?
The speed of light is 299,792,458 m/s.
What's a Light-Year?
A light-year is the distance light travels in one Earth year (365 days). A light-year is about 5,878,499,810,000 miles. Some stars you see can be light-years away, so the star may no longer be present even if you are seeing the it's light. That is because it takes years for the light to reach us, and in that time the star could have already exploded.