Illustration: NASA
Their evaluation seems convincing, says Andrew Rivkin, a planetary scientist at Johns Hopkins University’s Applied Physics Laboratory who research the composition of asteroids and who was not concerned in the paper. “Short of going and grabbing a piece, like NASA just did with Bennu, this is probably as close to conclusive as we get,” he says. Rivkin emphasizes that Kamo’oalewa is an uncommon object: Out of some 80,000 meteorites collected on Earth, solely a few % have come from the moon, and of the 1,382 meteorite falls noticed and documented by folks, none have been lunar.
The researchers discover that Kamo’oalewa has in all probability been hanging round for thousands and thousands of years, not a long time, like different objects in such orbits. But its orbit isn’t steady, due to the traditional three-body downside, by which the chaotic gravitational affect of three our bodies—the Earth, the solar, and Kamo’oalewa—will finally nudge it in order that it will get kicked out and flies away.
Their astronomical sleuthing continues, together with inspecting lunar craters which have remained basically undisturbed for eons. Small adjustments in the preliminary circumstances of the fashions, equivalent to the dimension of the asteroid that made the impression, the place it hit the moon, and at what angle, have dramatic results on an ejected lunar boulder’s trajectory. They infer a kilometer-sized asteroid made that important crash, and so they could make inferences about the impression too. “Based on the likely conditions to produce this kind of orbit, coming from the moon, that would require a crater millions of years old and tens of kilometers in size,” Castro-Cisneros says. It doubtless smashed into the trailing facet of the moon, he says, and so they’re now attempting to pinpoint the exact crater that Kamo’oalewa launched from.
Kamo’oalewa’s lunar provenance additionally has implications for probably hazardous Earth-bound asteroids that NASA and different organizations search the heavens for. It means folks also needs to take into account orbits originating from the moon, not simply rocks flung out of the asteroid belt. NASA is scoping for asteroids 140 meters in diameter and bigger, comparable in dimension to the one the DART spacecraft smacked into to check deflection methods. Near-Earth objects from historic moon impacts would in all probability be 100 meters or smaller, Malhotra says, however these are nonetheless often called “city killers,” harmful sufficient to trigger widespread destruction in the event that they have been to strike the Earth.
That in all probability gained’t be Kamo’oalewa’s destiny, however Malhotra and Castro-Cisneros’ analysis reveals that there are doubtless others on the market prefer it someplace.