A fast-rotating asteroid that orbits in conjunction with Earth It could be a stray piece of the moon. Now, scientists think they know exactly which lunar crater they came from.
A new study published April 19 in the journal Nature astronomyfinds that the ground is nearby asteroid 469219 Kamo'oalewa may have been launched into space when a mile-wide (1.6 km) space rock collided with the Moon, creating the Giordano Bruno Crater.
The reflection of Kamuwalewa's light matches that of weathered lunar rocks, and its size, age and rotation match the 13.6-mile (22 km)-wide crater, which lies on the far side of the moon, study researchers reported.
China plans to launch a mission to return samples to the asteroid in 2025. The mission, called Tianwen-2, will return pieces of Kamo'oalewa about two and a half years later, according to our sister site Live Science. space.com.
“The possibility of a lunar-derived origin adds unexpected intrigue to… [Tianwen-2] “The task poses additional technical challenges for sample return.” Bin Chengsaid a planetary scientist at Tsinghua University and co-author of the new study Sciences.
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Kamo'oalewa was discovered in 2016 by researchers at the Haleakala Observatory in Hawaii. It is about 100 to 200 feet in diameter (about 30 to 60 meters, or about the size of a large Ferris wheel) and rotates at a rapid clip of one revolution every 28 minutes. The asteroid orbits the sun in a similar path to Earth, sometimes approaching a distance of 10 million miles (16 million kilometers).
Follow-up studies indicated that the spectra of light reflected by Kamowalewa were very similar to spectra reflected from samples returned to Earth by lunar missions, as well as meteorites known to come from the Moon.
Cheng and his colleagues first calculated the size of the object and the impact velocity needed to eject a fragment like Kamualoa from the moon's surface, as well as the size of the crater it would leave. They discovered that the asteroid would have been the result of an impact at a 45-degree angle at a speed of about 420,000 miles per hour (18 kilometers per second) and would have left a crater 6 to 12 miles (10 to 20 kilometers) wide.
The researchers wrote in their paper that there are tens of thousands of craters of this size on the surface of the moon, but most of them are old. Near-Earth asteroids typically last only about 10 million years, or at most up to 100 million years before they collide with the sun or planet or exit space. Solar System completely. By looking at the small potholes, the team narrowed down the contenders to a few dozen options.
The researchers focused on Giordano Bruno, which met the size and age requirements. They found that the collision that formed Giordano Bruno could have created as many as three Kamuwalewa-like objects that still exist. The researchers concluded that this makes Giordano Bruno Crater the most likely source of the asteroid.
“It's like knowing which tree a leaf falling to the ground in a vast forest came from,” Cheng said Written on Xformerly known as Twitter.
Confirmation will come after the Tianwen-2 mission returns a piece of Kamo'oalewa to Earth. Scientists already have a sample of what is believed to be ejecta from Luna 24's Giordano Bruno crater, a small piece of moon rock that was brought to Earth on a NASA mission in 1976. By comparing the two, researchers were able to verify the origin of Kamowaleua.
Editor's Note: The headline for this article was updated on April 23 at 10 a.m. ET.