EarthSky | Piece of the moon? Asteroid might have lunar origin


This is an artist’s idea of Kamo’oalewa, a near-Earth asteroid that, in accordance with a brand new research, was initially a bit of the moon. Image through Addy Graham/ The University of Arizona.

Did you recognize that Earth has a tiny quasi-satellite known as Kamo’oalewa? It’s a near-Earth asteroid that is still pretty near Earth in its orbit across the sun. Researchers from the University of Arizona announced on November 11, 2021, that this asteroid may very well be a long-lost piece of the moon.

That is the main target of a brand new peer-reviewed paper that Communications Earth and Environment (Nature) published on November 11, 2021.

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An uncommon near-Earth asteroid

Kamo’oalewa is a near-Earth asteroid, of which there are 1000’s. Notably, these are asteroids that might doubtlessly pose an affect menace to Earth. They inhabit the inside solar system, and, subsequently, aren’t a part of the main asteroid belt between Mars and Jupiter.

This specific space rock is between 150 and 190 ft in diameter, in regards to the dimension of an unusual Ferris wheel, and will get as shut as 9 million miles (14.5 million km) to Earth. It remains to be, nonetheless, troublesome to detect. Indeed, as seen from Earth, it is rather faint, about 4 million instances dimmer than the faintest star that may be seen by the human eye.

Thousands of tiny moving dots with thin colored rings on black background.
There are 1000’s of near-Earth asteroids within the inside solar system, as depicted on this graphic. Kamo’oalewa is the primary one identified to have a composition just like that of Earth’s moon. Image through NASA/ JPL-Caltech/ Wikimedia Commons.

A moon-like mild spectrum

While Kamo’oalewa appears, for probably the most half, like some other near-Earth asteroid, the astronomers, nonetheless, discovered a shock. Its sample of mirrored mild, known as a spectrum, was totally different than the opposite asteroids. In distinction, it didn’t appear to be the spectrum from any of the them. As Ben Sharkey, lead creator of the research, noted:

I appeared via each near-Earth asteroid spectrum we had entry to, and nothing matched.

In reality, it appeared quite a bit just like the spectrum seen in rocks from the moon.

Smiling young man in black and yellow plaid shirt.
Ben Sharkey, a graduate pupil on the University of Arizona, led the brand new analysis about Kamo’oalewa and its origins. Image through The University of Arizona.

As defined within the paper:

This spectrum is indicative of a silicate-based composition, however with reddening past what is often seen amongst asteroids within the inside solar system. We evaluate the spectrum to these of a number of materials analogs and conclude that one of the best match is with lunar-like silicates. This interpretation implies in depth space weathering and raises the prospect that Kamo’oalewa might comprise lunar materials.

In this case, the researchers found the bizarre properties of the asteroid through the use of the University of Arizona-managed Large Binocular Telescope on Mount Graham in southern Arizona. Researchers additionally obtained some information with the Lowell Discovery Telescope in Flagstaff, Arizona. Co-author Al Conrad stated:

These difficult observations had been enabled by the immense light-gathering energy of the dual 8.4-meter telescopes of the Large Binocular Telescope.

A misplaced piece of the moon?

Hence, for the previous three years, the researchers have been trying to find an evidence for Kamo’oalewa. Co-author Vishnu Reddy stated:

We doubted ourselves to loss of life.

As Sharkey added, the ultimate outcome gave the impression to be, surprisingly, that the asteroid originated from the moon:

This spring, we bought a lot wanted follow-up observations and went, ‘Wow, it is real.’ It’s simpler to clarify with the moon than different concepts.

Also, Kamo’oalewa’s orbit is just like Earth’s however barely tilted. This, once more, is totally different from different near-Earth asteroids. Coupled with the spectrum proof, the tilted orbit additionally means that the asteroid initially got here from the moon.

Various colored thin concentric rings on black background with text annotations.
The orbit of Kamo’oalewa (often known as 2016 HO3). Image through Tomruen/ Wikipedia.

According to co-author Renu Malhotra:

It may be very unlikely {that a} garden-variety near-Earth asteroid would spontaneously transfer right into a quasi-satellite orbit like Kamo’oalewa’s. It won’t stay on this specific orbit for very lengthy, solely about 300 years sooner or later, and we estimate that it arrived on this orbit about 500 years in the past.

Kamo’oalewa is a part of the Apollo group of asteroids. Scientists utilizing the Pan-STARRS telescope at Haleakala Observatory in Hawaii found it on April 27, 2016. Its title, present in a Hawaiian creation chant, alludes to an offspring that travels by itself.

Bottom line: Astronomers on the University of Arizona say {that a} peculiar near-Earth asteroid may very well be a misplaced piece of the moon that broke off within the historical previous. If so, it might be the primary identified asteroid to have originated from Earth’s solely pure satellite.

Source: Lunar-like silicate material forms the Earth quasi-satellite (469219) 2016 HO3 Kamo’oalewa

Via the University of Arizona

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