Astronomers studying the star Fomalhaut, just 25 light-years away, initially thought they found a new planet, called Fomalhaut b. This object appeared to shine with the light from its star. However, over time, this light faded, and researchers spotted a second bright object nearby, prompting a re-evaluation of their findings from nearly two decades.
A recent study in Science suggests that instead of a planet, the original bright spot was likely the result of a collision between two asteroid-sized bodies, creating a cloud of glowing debris. The discovery of another similar light boosts this new interpretation.
The initial observations in 2008 suggested Fomalhaut b was a young planet, but it turned out to represent a chaotic event rather than a stable celestial body. By 2023, the original light source vanished entirely, leading scientists to rethink their analysis. Paul Kalas, an astronomer at UC Berkeley, noted that such a collision has never been documented in our solar system.
“It’s absent in all of our previous Hubble images,” Kalas said. “This means we witnessed a violent collision and a debris cloud similar to nothing we see around our own sun.”
The second bright object, named cs2, closely resembles the first, reinforcing the theory that both are clouds of dust rather than actual planets. The aftermath of these collisions is quite surprising. Astronomical collisions are generally rare, with estimates suggesting they occur once every 100,000 years. Yet in under 20 years, researchers have observed two significant events in the Fomalhaut system.
“Catching these events in real-time provides invaluable insights into how planets form,” said Jason Wang, an astrophysicist at Northwestern University. His analyses confirmed the presence of unexpected light sources near the star.
The recent findings suggest that the Fomalhaut system is much more dynamic than previously thought. According to a study published on December 18, 2025, multiple analyses detected the new light sources, indicating that astronomers are witnessing significant activity in this region of space.
“All analyses consistently detected a new source around the star,” Wang added.
These discoveries not only change our understanding of planetary formation but also serve as a warning for future space missions. Both cs1 and cs2 closely resemble exoplanets, raising concerns for upcoming missions that rely on reflected light to identify new worlds.
“This is a cautionary note for future missions,” Kalas mentioned, referring to observatories like the Giant Magellan Telescope. “Fomalhaut cs2 appears to be an extrasolar planet reflecting starlight.”
With Hubble’s aging equipment no longer reliable, attention now shifts to the James Webb Space Telescope. Wang’s team is slated to use Webb’s Near-Infrared Camera (NIRCam) to analyze cs2. Webb’s advanced instruments can measure dust grains’ size, composition, and even temperature, possibly detecting water or ice if they exist.
These findings pave the way for a new roadmap in detecting distant worlds, proving that sometimes what seems like a planet may just be a beautiful cosmic illusion.
