Editor’s note: This article was originally published Aug. 13, 2025, and has been updated to include new text and illustrations featured in the January 2026 issue of Astronomy. Using an artificial ...

I love simple questions that wind up having complicated—or at least not straightforward—answers. Astronomers twist themselves into knots, for example, trying to define what a planet is, even though it ...

A spoonful of this star's matter can weigh a billion tons. When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. By developing a new theoretical ...