NewsBytes Explainer: Why interstellar comet 3I/ATLAS is breaking apart
The NASA-funded ATLAS survey in Chile spotted the interstellar comet 3I/ATLAS in July 2025.
Now, as it heads out of our solar system, it's made headlines by erupting—making it only the third confirmed visitor from another star system that we've ever seen.
How did the comet start breaking apart?
Unlike most comets, 3I/ATLAS started losing water at a wild rate—about 40kg every second—even when it was pretty far from the Sun.
In December, NASA's SPHEREx satellite caught the comet cracking open and releasing ancient material that's billions of years old.
Observations of the comet
The comet's core is wrapped in a hazy glow. It got much brighter after swinging past the Sun last October and was observed by ground telescopes in December as it exited the inner solar system.
NASA's TESS observed it in mid-January.