The Moon has endured countless impacts over millions of years, with asteroids and meteors leaving its surface pockmarked with craters. More recently, it has also been struck by small probes and landers sent by Earth's space agencies.

Now, on Wednesday, scientists expect the Moon to experience yet another collision, this time from a drifting SpaceX rocket traveling at approximately 2.43 kilometers per second, or about 5,400 mph.

The upper stage of a SpaceX Falcon 9 rocket will "impact" the Moon on August 5, according to NASA's Center for Near-Earth Object Studies (CNEOS). The US space agency reached this conclusion after independent astronomers, using public data, noted that a portion of the rocket from a January 2025 launch was on an accidental collision course with the Moon.

"There is no danger to Earth," said spokesperson Jimi Russell. "NASA will continue to track the booster for training purposes, as well as later observe the impact site for scientific purposes."

SpaceX launched this specific Falcon 9 rocket as part of a US-Japanese mission to carry a pair of lunar landers and scientific equipment to the Moon last year. Part of the Falcon 9 is reusable and designed to return to Earth for its next mission. However, parts of the rocket are shed in space and remain there, stuck in orbit unless they eventually collide with another celestial body.

The piece in question is the upper stage of the rocket, about the size of a five-story building, with a weight on Earth of at least 4,000 kg (8,800 lbs). Astronomer Bill Gray, who first discovered the trajectory, says the object will land near the Einstein Crater, which is on the part of the Moon that receives daylight and is visible from Earth. He predicts it will create a crater more than 17 meters (56 feet) in diameter.

The impending collision, predicted to occur at about 02:35 EDT (06:35 GMT) on Wednesday, is expected to captivate astronomers, both amateur and professional. "It's something really huge smashing into the Moon. It's not remotely dangerous, we can just watch the show," says Dr. Matt Bothwell, public astronomer at the University of Cambridge.

"It's going to impact and it's going to send up a huge plume of dust, maybe 50 km into the air or more, and that's going to spread sideways over time," Bothwell said. Given the Moon's lack of atmosphere and far weaker gravitational pull, the moment of impact will be "more impressive than any [similar] explosion on Earth," Bothwell added.

Nothing will slow the object down, like the atmosphere would do here on Earth, and nothing will prevent the estimated million kilograms of debris from rocketing up into space. While the impact will not be visible from Earth with the naked eye, people with access to a sophisticated telescope may be able to see a flash radiating off the Moon's surface, Bothwell said.

More significant would be the educative potential of the impact, Bothwell noted. He said this moment would present a unique opportunity to study what happens when an object hits the Moon. Scientists are therefore gearing up to watch the event closely.

Big telescopes in the Americas, plus NASA's Lunar Reconnaissance Orbiter and South Korea's Danuri probe, will track the flash, plume, and new crater, and a citizen-science project is signing up keen amateurs to film the impact too. By catching the dust plume in action, astronomers hope to turn this accidental crash into a useful experiment.

Watching how much material gets thrown up, how high it goes, and how it falls back should sharpen their models of lunar impacts – and even give clues about what lies just beneath the surface at the impact site, where fresh subsurface material will be exposed for the first time.

Bothwell also said the collision would provide a cautionary tale about the issue of ever-accumulating, human-made space clutter. "I think more people should be more worried about space debris," Bothwell said. "Every single year we put more stuff in orbit. Sometimes the satellites just collide, and they shatter into more pieces. I think there's a worry about a runaway cascade, if we put so much stuff in orbit."

According to the European Space Agency (ESA), there are around 54,000 objects floating in space that measure larger than 10 cm. In total, humans have launched about 17,000 tonnes of objects into space since the Space Age began in 1957. The last dead rocket to impact the Moon was in 2022, when the Chinese Long March 3C upper stage from the 2014 Chang'e 5-T1 mission hit the far side of the Moon - which faces away from Earth.

Decades earlier, NASA launched objects into the Moon on purpose, in order to collect data for the Apollo missions.

Source: www.bbc.co.uk