Their evaluation appears to be like convincing, says Andrew Rivkin, a planetary scientist at Johns Hopkins College’s Utilized Physics Laboratory who research the composition of asteroids and who was not concerned within the paper. “In need of going and grabbing a chunk, like NASA simply did with Bennu, that is most likely as near conclusive as we get,” he says. Rivkin emphasizes that Kamo’oalewa is an uncommon object: Out of some 80,000 meteorites collected on Earth, only some % 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 most likely been hanging round for thousands and thousands of years, not many years, like different objects in such orbits. However its orbit isn’t steady, because of the traditional three-body drawback, by which the chaotic gravitational affect of three our bodies—the Earth, the solar, and Kamo’oalewa—will ultimately nudge it in order that it will get kicked out and flies away.
Their astronomical sleuthing continues, together with analyzing lunar craters which have remained basically undisturbed for eons. Small adjustments within the preliminary situations of the fashions, corresponding to the dimensions of the asteroid that made the influence, 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 essential crash, they usually could make inferences concerning the influence too. “Based mostly on the seemingly situations to provide this sort of orbit, coming from the moon, that may require a crater thousands and thousands of years outdated and tens of kilometers in measurement,” Castro-Cisneros says. It seemingly smashed into the trailing facet of the moon, he says, they usually’re now making an attempt 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 contemplate 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, related in measurement to the one the DART spacecraft smacked into to check deflection strategies. Close to-Earth objects from historical moon impacts would most likely be 100 meters or smaller, Malhotra says, however these are nonetheless generally known as “metropolis killers,” harmful sufficient to trigger widespread destruction in the event that they have been to strike the Earth.
That most likely received’t be Kamo’oalewa’s destiny, however Malhotra and Castro-Cisneros’ analysis reveals that there are seemingly others on the market prefer it someplace.