A floating piece of SpaceX rocket has crashed into the Moon at 8,690 kilometres per hour, as predicted, after drifting off course for the past year.Although no-one observed the actual collision, a telescope in Chile spotted what astronomers have identified as evidence of a stream of debris.The European Southern Observatory's Very Large Telescope in Chile detected a debris plume. (AP: Esteban Felix/File)NASA and its Lunar Reconnaissance Orbiter probe and South Korea's Pathfinder Lunar Orbiter were planning to take images of the site after impact, but it could take days to receive that information.At the Paranal Observatory in Chile, the European Southern Observatory's (ESO's) Very Large Telescope detected glimmers of light associated with the impact."We can confirm that the telescope detected spectral lines of sodium and lithium gas in the impact plume lasting for 5 to 10 minutes after impact," an ESO spokesperson said.The school-bus-sized object is the second stage of a SpaceX Falcon 9 rocket that had launched a lunar lander from Firefly Aerospace toward the Moon in January 2025. Weighing 4,000 kilograms, the rocket body slammed into the Moon about 4:35pm AEST on Wednesday.The impact occurred near the Moon's terminator line, or the boundary of its shadow between the sunlit side and its far side. Similar to past objects that have hit the Moon, the rocket stage kicked up a plume of lunar dust that was briefly illuminated by sunlight, but difficult to spot with the naked eye from Earth.How the impact plume interacted with the sunlight allowed astronomers to glean clues about its composition.The sodium gas evidenced in the spectra is believed to have originated from the lunar soil, while the traces of lithium may have come from the rocket stage itself, according to Carl Schmidt, the lead astronomer conducting the impact observations."This observation did not go perfectly and this is a very crude analysis, but I wanted to share something quickly, and we can say more about these results in time," he said.The rocket piece is understood to have hit near Einstein Crater on the Moon's western limb, which is often difficult to see from Earth.Topographic data showing Einstein, a fairly large crater that spans 198 kilometres. (Supplied: NASA)SpaceX's Julianna Scheiman said this week that the company was working with NASA to avoid future wrecks, stressing that this projected crash was not deliberate. A combination of solar activity and gravity accidentally put it on a collision course with the Moon, she said.Cosmic forces nudged piece to MoonSuch stages typically fall back into Earth's atmosphere and burn up or plunge into the ocean after boosting the rocket's payload to a precise spot in orbit.But because the January lunar lander mission required more thrust than missions closer to Earth, the rocket's second stage remained in space, floating aimlessly among thousands of other pieces of space junk that active satellites must steer clear of.The rocket stage is leftover junk from a January 2025 Moon mission. (AP: John Raoux/File)It was not until earlier this year that astronomers determined that the rocket stage, which had dumped its remaining fuel and could not be controlled, was on an orbital trajectory ending at the Moon."What has happened is essentially a mixture of solar activity and gravity forces have put it on a path toward the Moon," Ms Scheiman, SpaceX director of NASA science and Dragon programs, told reporters on Monday."This may be of some, probably minor, scientific interest, and we may learn some things from it," said Bill Gray, creator of widely used astronomy software Project Pluto, who appeared first to calculate and publish a report predicting the stage's impact in April."By January, I was pretty sure it would hit, though with only a vague idea as to where it would do so. By April, I was confident enough to post an announcement," he said.Mr Gray said the impact presented no danger to anyone, "though it does highlight a certain carelessness about how leftover space hardware [space junk] is disposed of".Space junk impacts on the Moon are rareA Chinese rocket stage crashed into the Moon in March 2022 after completing a lunar test mission. In 2009, NASA intentionally crashed a rocket stage into the Moon to study the plume of lunar material kicked up by the impact, leading to a key discovery that lunar dirt contains traces of water ice.Several spacecraft intending to softly land on the Moon in recent years have crashed instead. Russia's nuclear-powered Luna-25 mission spun out of control and crashed in 2023. Its small power source of plutonium-238 likely remains harmlessly on the lunar surface.India's Chandrayaan-2 lander mission crashed in 2019. Israel's Beresheet lander crashed that same year. Among the Israeli lander's payloads were tiny tardigrades, microscopic animals that are known for surviving radiation and other harsh environments and which may still be on the surface.NASA intentionally crashed stages from its Saturn V Moon rocket into the Moon in the 1970s to study the seismic effects of the impacts.The US space agency plans to build a lunar base and send routine astronaut missions to the lunar surface beginning later this decade under its multi-billion-dollar Artemis program. It would not want errant pieces of space junk impacting those assets.Reuters/AP