What Is Up With Bennu's Missing Craters? Researchers Explain Asteroid's Age, Crumple Zone

Asteroid Bennu, the closest and possibly most dangerous asteroid approaching Earth, continues to amaze astronomers. The asteroid Bennu's surface behaves as a collapsing zone that can absorb impacts. This information will cause humanity to reevaluate how they destroy asteroids that threaten our world.

The surface of the asteroid Bennu is covered with craters. Data from NASA's OSIRIS-REx mission, on the other hand, shows that some of the craters have mysteriously gone. The findings indicate that the 0.3-mile (0.5-kilometer) wide space rock observed by the American space probe is experiencing some unexpected geological processes.

Researchers published their study, "Crater population on asteroid (101955) Bennu indicates impact armouring and a young surface," in the journal Nature Geoscience.

(Photo : Joel Kowsky/NASA via Getty Images)
CAPE CANAVERAL, FL - SEPTEMBER 8: In this handout photo provided by NASA, The United Launch Alliance Atlas V rocket carrying NASA's Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) spacecraft lifts off on from Space Launch Complex 41 on Thursday, Sept. 8, 2016 at Cape Canaveral Air Force Station in Florida. OSIRIS-REx will be the first U.S. mission to sample an asteroid, retrieve at least two ounces of surface material and return it to Earth for study. The asteroid, Bennu, may hold clues to the origin of the solar system and the source of water and organic molecules found on Earth.

Asteroid Bennu's Mysterious Craters

Between 2018 and 2021, NASA's OSIRIS-REx probe studied the near-Earth asteroid Bennu for approximately two and a half years. Next year, the land probe will transmit microscopic particles of space rock to Earth. Scientists have studied thousands of photos and data obtained by OSIRIS-REx.

Bennu, according to Edward "Beau" Bierhaus, a Lockheed Martin space science researcher and main author of a recent publication, is one of the most well-studied bodies in the solar system, with a plethora of data and photographs.

"We've collected thousands and thousands of images and literally billions of LIDAR measurements that give us the topographic shape of Bennu," Bierhaus told Space.com. "Now we have the most detailed topographic map of anybody in the solar system."

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Bierhaus and his colleagues sifted through thousands of photographs for months. They discovered more about how asteroids generate craters, and what they discovered startled them.

Bennu has a lot of craters, with a width of 484 meters. Scientists discovered almost 1,500 of them, with lengths ranging from 1 to 200 meters. The researchers then compared this figure to information on the frequency and severity of crater-forming impacts on Earth, the moon, and other celestial bodies. According to the figures, scientists should have discovered many more impact scars.

Bennu's Age Unveiled

According to the same Space.com report, Bennu has also thrown in some unexpected twists and turns. The scientists discovered that, unlike the moon, Bennu does not preserve a long record of its prior contacts when they studied the features and distribution of the asteroid's craters.

While the asteroid itself is up to a billion years old, its continually changing surface is relatively new, and traces of past occurrences are wiped out on average every few million years.

Bennu, according to Bierhaus, is about 2 million years old. It's one of the solar system's crater-derived surface ages that we've observed.