EVERYDAY SCIENCE

Detailed explanation-1: -Light-year is the distance light travels in one year. Light zips through interstellar space at 186, 000 miles (300, 000 kilometers) per second and 5.88 trillion miles (9.46 trillion kilometers) per year.

Detailed explanation-2: -For the same reason, astronomers don’t use miles to measure vast distances in space. Instead, they use light-years: the distance that light travels in a year. That makes Proxima Centauri, the closest known star to the Sun, 4.28 light-years away; that’s a lot easier than saying 24, 000, 000, 000, 000, 000 miles.

Detailed explanation-3: -Astronomers use an effect called parallax to measure distances to nearby stars. Parallax is the apparent displacement of an object because of a change in the observer’s point of view.

Detailed explanation-4: -Measuring Space With Parsecs Because space is so big, many astronomers do not like to say how far away things are using miles or kilometers. Instead, we use a measurement that we call a parsec. Remember Alpha Centauri, the closest star? It is 1.347 parsecs, or 41, 560, 000, 000, 000 (or 41.56 trillion) kilometers away.