Interstellar comet 3I/ATLAS has gone from a faint outsider to one of the most closely watched visitors in the Solar System, ...

What is the difference between a moon and a planet? Trick question! According to scientific definitions, there often isn’t much of a difference at all. That might seem counterintuitive, but it’s true.

Galaxies come in many shapes and sizes, and trying to define them is difficult In keeping with both trend and theme, it’s time to take a step outward—a big step. If you're enjoying this article, ...