2024 PT5: the asteroid that almost makes us believe in the (second) moon

This would be an irony of which only the cosmos has the secret: 2024 PT5, often referred to as a temporary second moon, has every chance of being lunar debris carried into space by a meteorite impact.

The asteroid was discovered in August 2024 and follows an orbit similar to that of Earth, which it approached before being partially captive between last September and October. Once again, at the start of the year, it finds itself quite close to Earth, but too far to be visible to the naked eye. Its current distance is approximately 1,700,000 km.

Is it a near-Earth cruiser, is it a rocket?

2024 PT5 is the size of a bus, or around ten meters. Scientists first thought it was a classic near-Earth asteroid, that is to say an object whose orbit takes it a short distance from our planet. Then they considered it as potential rocket debris, because there are quite a few of them in our near space. It was the Lowell Observatory, in the United States, which made it possible to decide the artificial or natural origin of the almost quasi-moon. Indeed, its reflectance properties show that it is made of rocks rich in silicates, so it cannot be human debris.

However, this object does not resemble any known asteroid. It seems rich in pyroxenewhich indicates a magmatic environment or one having undergone lasting stress (metamorphic rocks). Hey, this corresponds perfectly to our satellite, the real one, aka the Moon!

The most likely scenario is therefore that the latter suffered a violent impact, in the more or less distant past, from an object massive enough to lift debris, including one of approximately 10 m which slowly approached the Earth's orbit (see Fun Fact below).

A veritable reservoir of pieces of the Moon

Another interesting observation is that this is the second time that Solar System watchers have detected one of these objects potentially coming from the Moon. Once, the phenomenon can be judged exceptional; twice, this indicates that there could be a reservoir of these pieces of the Moon. For now, scientists estimate that there are 16 of these near-Earth asteroids with lunar origin, but there could be more, more or less mixed in with more conventional near-Earth asteroids.

2024 PT5 is being monitored by many astronomers across the globe, including groups at NASA. Among them stands out the Deep Space Networkresponsible (among other things) for spying on bodies that approach a little too close to our cow floor. One final clarification on this subject: there is absolutely no risk of 2024 PT5 colliding with the Earth!