Two asteroids crashed around a nearby star, solving a cos...

What’s Happening

Let’s talk about A pair of nascent planets have been caught smashing together around the nearby star Fomalhaut, and in doing so have solved the puzzle of its famous ‘planet’ Space Two asteroids crashed around a nearby star, solving a cosmic mystery A pair of nascent planets have been caught smashing together around the near, and in doing so have solved the puzzle of its famous ‘planet’ By Leah Crane 18 December 2025 Facebook / Meta Twitter / X icon Linkedin Reddit Email A composite image of the dust belt around Fomalhaut (obscured in the middle).

In the inset, dust cloud cs1, imaged in 2012, is pictured with dust cloud cs2, imaged in 2023 NASA, ESA, Paul Kalas/UC Berkeley Around the near, asteroids are smashing into each other in a series of cosmic cataclysms, creating huge clouds of dust. For the first time, astronomers are watching one of these collisions as it occurs, which could provide a window into the early days of our own solar system. (yes, really)

Fomalhaut has a history of strange observations: in 2008, Paul Kalas at the University of California, Berkeley, and his colleagues reported what seemed to be a giant planet in orbit around the young star, based on observations with the Hubble Space Telescope made in 2004 and 2005.

The Details

Over the years, though, as more observations have rolled in, researchers have hotly debated over what this strange object, called Fomalhaut b, might be. It was either a planet a bit larger than Jupiter, or a cloud of debris.

Now, Kalas and his team have used Hubble to look at Fomalhaut once again. “In 2023, we used the same instrument we’d used [before], and we did not detect Fomalhaut b – it wasn’t visible anymore,” says Kalas.

Why This Matters

“But what fr shocked us was [that] there was a new Fomalhaut b. ” This new bright spot, called Fomalhaut cs2 (short for “circumstellar source”), couldnt be a planet, or it would have been seen sooner. The best explanation is that it is a cloud of dust created by the collision of two large asteroids , or planetesimals, each around 60 kilometres in diameter.

This could have implications for future research in this area.

The Bottom Line

The best explanation is that it is a cloud of dust created by the collision of two large asteroids , or planetesimals, each around 60 kilometres in diameter. The disappearance of Fomalhaut b hints that it was probably a similar dust cloud all along.

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