A Piece of a SpaceX Rocket Is About to Crash into the Moon

A leftover piece of a SpaceX Falcon 9 rocket is heading toward the Moon and is about to crash into it. Scientists say the impact will make a crater and a tiny flash of light that some people on Earth might see. While no one is in danger, the event is sparking an important debate about space junk and who is responsible for keeping the Moon clean.

Professor Katarina Miljkovic is a planetary scientist at Curtin University in Australia. She explained that most rocket parts fall back to Earth after a launch, but sometimes a piece gets stuck drifting in space. If that piece crosses the Moon's path, a crash can happen, and that is exactly what occurred with this rocket stage.

Because the Moon has no atmosphere, the rocket piece won't burn up the way it would falling toward Earth. It will hit the surface directly and release a burst of energy, leaving behind a crater. Scientists may also spot a quick flash of light — called a lunar impact flash — for just a millisecond.

The crash is expected to happen around 4:35 p.m. Australian Eastern Standard Time, which means people in Australia will be in daylight and won't see it. However, people in eastern North America and much of South America should have the best chance of spotting the flash. Scientists will also use telescopes and satellites to study what happens.

The crash will shake the Moon and send seismic waves — a bit like a small moonquake — rippling through it. Professor Miljkovic said that because the Moon is smaller and drier than Earth, those waves travel fast and make the Moon 'ring.' This is useful information for future astronauts who may live on the Moon one day.

The surface of the Moon where the rocket hits is made of a material called regolith. The crash could melt it, vaporize it, or break it apart. Professor Miljkovic compared it to a lawnmower reworking the top layer of soil, and said understanding regolith is very important for future Moon bases.

Not everyone is focused only on the science. Space lawyer Gregory Radisic is worried about what this crash means for the future of the Moon. He said accidents like this leave a permanent mark because there is no weather on the Moon to wash anything away, so the damage could last for years and years.

Mr. Radisic also said there is no clear warning system to alert the world when space debris is about to cause an accident. He noted that most people only heard about this crash from a single science paper, not from any official notice. He believes countries and companies need a much better way to share information before accidents happen.

One idea Mr. Radisic supports is a warning system like the 'Notices to Air Missions' that pilots use to stay safe. He said debris from a crash can fly into space at very high speeds and damage satellites or endanger astronauts. A warning system could give space operators time to move equipment or prepare for the impact.

The 1967 Outer Space Treaty is the main law that covers space, and it mentions communication between countries. However, following the treaty is voluntary, and Mr. Radisic says real, practical rules are needed as more governments and companies head to the Moon. Professor Miljkovic agreed that as humans plan to spend more time on the Moon, taking better care of it will become more and more important.