WHAT IS A LIGHT YEAR?
How we measure vast distances across the universe
Reported by Tim Childers and Jon Gordon
Alight year is a measurement of distance and not time, as the name might suggest. A light year is the distance a beam of light travels in a single Earth year, or around 9.7 trillion kilometres (6 trillion miles). On the scale of the universe, measuring distances in kilometres or miles just doesn’t cut it. In the same way that you may measure the distance to the supermarket in the time it takes to drive there, astronomers measure the distances of stars in the time it takes for their light to travel to us. For example, the nearest star to our Sun, Proxima Centauri, is 4.2 light years away.