Red-light devices are all over social feeds and make enormous promises. From the many, we find the few that are actually worth your commitment, time, and money.

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.

An explosion seen in the cosmos in the early 1600s may actually be an "Alien Type Ia supernova", according to a new paper. In ...