Hubble images reveal that two bright features near the young star Fomalhaut were not planets but dust clouds produced by collisions between large space rocks at least 37 miles (60 km) across. Such impacts in the same region are thought to be extremely rare, making two events within 20 years either an unlikely coincidence or a sign that these collisions are more common than believed. Researchers will keep monitoring the new dust cloud to track its evolution and test formation models.
Hubble Spots Dust From Two Massive Collisions Near Fomalhaut, Not Planets
This illustration provided by NASA in December 2025 depicts the aftermath of a collision between two massive space rocks orbiting the star Fomalhaut. (NASA, ESA, STScI, Ralf Crawford, Space Telescope Science Institute via AP)
NASA’s Hubble Space Telescope has captured a rare view of the aftermath of two separate cosmic collisions near the young star Fomalhaut, helping researchers solve a decades‑old mystery about apparent “planets” that turned out to be clouds of dust.
Years ago, astronomers identified a dense, bright feature close to Fomalhaut and tracked it as a possible planet. New Hubble images taken in 2023 showed that the original bright feature had vanished and a different bright spot had appeared nearby — a dramatic change that signaled these were not planets but transient dust clouds created by collisions between large space rocks.
Dust Clouds From Giant Impacts
Researchers conclude the two bright sightings were clouds of debris produced when massive planetesimals — each at least about 37 miles (60 kilometers) across — smashed together. The impacts generated dense dust plumes that were bright enough to mimic the appearance of planets at optical wavelengths; over time the dust spreads out and fades from Hubble’s view.
“It’s highly unexpected that this area has now exhibited two, unique, massive collisions inside 20 years,” said Joshua Lovell of the Harvard‑Smithsonian Center for Astrophysics, who was not involved in the new study, which appears in the journal Science.
Models suggest collisions of this scale in the same region should be extremely rare — roughly once every 100,000 years — so seeing two events within two decades is either a remarkable stroke of observational luck or an indication that such smashups are more frequent than current theories predict. Additional observations will be needed to tell which is the case.
Why This Matters
Collisions between large planetesimals are fundamental to planet formation and to determining the composition and architecture of planetary systems. “Studying them is like taking a toddler picture of our solar system,” said astrophysicist Meredith MacGregor of Johns Hopkins University, who was not part of the research team.
Scientists plan to continue monitoring the new dust cloud over the coming years to watch how it evolves and disperses. The star lies in our cosmic neighborhood, about 25 light‑years from Earth (one light‑year is roughly 6 trillion miles), which makes it easier to study these dramatic events in relative detail.
“By keeping an eye on it, scientists are catching these violent explosions in real time,” said study author Paul Kalas of the University of California, Berkeley.
