Astronomers have made an exciting discovery: a sudden, bright flash on the Moon caused by something crashing into it. They’re still figuring out what exactly happened, but it may involve one of the strangest objects floating around in space.
This incredible scene was caught by the Armagh Observatory and Planetarium in Northern Ireland precisely at 03:09 am UTC on December 12, 2025. Andrew Marshall-Lee, a PhD student in his final year at the observatory, observed the phenomenon through the Armagh Robotic Telescope – and, impressively, he witnessed the event as it was happening.
Marshall-Lee shared his excitement, saying, “This makes it extra special (and saved me hours of processing what I recorded afterwards!). I genuinely think that I could spend years hunting for these impacts and might not see another one like it.” He told IFLScience.
The brief flash was due to a small object, likely no bigger than a golf ball, slamming into the Moon at an incredible speed. When the object hit the lunar surface, its kinetic energy transformed into heat and light in an instant, creating a shot of brightness that could be observed from Earth with a powerful telescope.
“We’re still working on determining the exact size, but typically, these objects measure about 3-5 cm across. The key thing to note is the high velocity of these meteoroids. It’s the impact speed that produces the vast amount of kinetic energy, which gets released as heat and light upon impact. We estimate it struck at about 35 km/s, which is about the speed you’d expect from a Geminid meteor,” explained Marshall-Lee.
He also indicated where the impact likely took place: “For now, it seems to have hit roughly 2 degrees northeast of the Langrenus crater.”
Such on-the-spot captures are incredibly rare; these flashes are brief and visible for only an instant, plus the Moon is vast. According to the AOP, this marks the first documented lunar impact flash observed from Ireland, and just the second ever recorded in the entire British Isles.
There’s a good chance that this lunar flash is connected to the ongoing Geminid meteor shower, which runs from December 4 to 20 and peaked recently. The observatory is still looking into this possibility. The Geminids arise from debris from an unusual asteroid known as 3200 Phaethon. As these small rocks enter Earth’s atmosphere, they create spectacular bright trails across the night sky.
Once in a while, a fragment might miss our planet and strike the Moon instead. With no atmosphere to provide protection, the lunar surface takes these hits straight on, resulting in brief bursts of light.
With a few days left of the Geminid shower still to go, more impacts on the Moon could be coming. Keep an eye on the sky!
Note: Edited 19/12/2025: An earlier version of this piece mentioned that the impact occurred on the Moon’s “dark side.” While the event did take place on the portion of the Moon that wasn’t lit up during the new Moon phase, it happened on the near side visible from Earth. The term “dark side” is often mistaken in this context, so we’ve removed it to avoid any confusion.
