How do we know 3I/ATLAS, also called comet C/2025 N1 (ATLAS), is interstellar? Will it strike Earth? Can we visit it? Here are all of your questions answered.

A mystery interstellar object discovered last week is likely to be the oldest comet ever seen—possibly predating our solar system by more than 3 billion years, researchers say.

The ATLAS (short for Asteroid Terrestrial-impact Last Alert System) is a NASA-funded program developed by the University of Hawaii. It incorporates data from four ground-based telescopes, two in Hawaii, one in Chile, and one in South Africa, to scan the entire sky twice a night, looking for asteroids and other impactors.