We measure the extremely long distances between things in space by light years. A light year is the distance that light travels in one Earth year. Light travels at about 300,000 kilometres per second.

Proxima Centauri b is the closest known exoplanet to our solar system that is thought to be within the habitable zone of its star.

Just the third-ever confirmed interstellar object has been detected in our solar system. Here's what we know. (Spoiler: It's ...