Hubble Accidentally Catches Comet Breaking Up

In a happy twist of fate, NASA’s Hubble Space Telescope just witnessed a comet in the act of breaking apart. The chance of that happening while Hubble watched is extraordinarily miniscule.

Comet K1, whose full name is Comet C/2025 K1 (ATLAS)—not to be confused with interstellar comet 3I/ATLAS—was not the original target of the Hubble study.

Before it fragmented, K1 was likely a bit larger than an average comet, probably around 5 miles across. The team estimates the comet began to disintegrate eight days before Hubble viewed it. Hubble took three 20-second images, one on each day from November 8 through November 10, 2025. As it watched the comet, one of K1’s smaller pieces also broke up.

Because Hubble’s sharp vision can distinguish extremely fine details, the team could trace the history of the fragments back to when they were one piece. That allowed them to reconstruct the timeline. But in doing so, they uncovered a mystery: Why was there a delay between when the comet broke up and when bright outbursts were seen from the ground? When the comet fragmented and exposed fresh ice, why didn’t it brighten almost instantaneously?

Sometimes the best science happens by accident!

For more information, visit science.nasa.gov/mission/hubble

Credit: NASA's Goddard Space Flight Center
Paul Morris: Lead Producer
Original Story Written by: Ann Jenkins / Christine Pulliam of the Space Telescope Science Institute

Video Credits:
Milky Way with comets timelapse. Credit: POND5


Comet Shoemaker Levy colliding with Jupiter from ESA's movie "15 Years of Discovery". Credit: ESA/Hubble (M. Kornmesser & L. L. Christensen)
Comet K1 Image. Credit: NASA, ESA, D. Bodewits (Auburn). Image processing: J. DePasquale (STScI).

Diagram of K1’s path through the Solar System. Credit: NASA, ESA, R. Crawford (STScI)


Music Credit:
“Le nozze di Figaro” by Wolfgang Amadeus Mozart via Chappell Recorded Music Library Ltd [PRS] and Universal Production Music