In asteroids, rock fractures develop due to stresses caused by daily temperature changes on spatial scales ranging from millimeters to metres. however, Time scales of rock fracture due to thermal stress are limited to observations.
Currently NASA OSIRIS-REx scientists They found that the sun’s heat breaks down the rocks of asteroid Bennu in just 10,000 to 100,000 years. This data also He revealed that surface renewal occurs much faster on asteroids than on Earth.
For the results, the team analyzed rock fractures in asteroid benno starting from High-resolution images taken by the OSIRIS-REx spacecraft (Origins, Spectral Interpretation, Resource Identification, Security Explorer-Regolith). Their findings have just been published in the journal natural earth sciences.
This information will help scientists estimate how long it takes rocks on asteroids like Bennu to break down into smaller particles, which can be blasted out into space or remain on the asteroid’s surface. Tens of thousands of years may seem very slow, but “we think it took a few million years to regenerate the surface of asteroids.”He said Marco DelbogPrincipal Study Scientist and Laboratory Researcher Nice Lagrange at the University of Côte d’Azur, France.
“We were surprised to learn that, geologically speaking, aging and the weathering process in asteroids occurs very quickly.” Rapid temperature changes in Bennu have resulted in internal stress that cracks and shatters rocks, similar to what happens Like cold glass breaking under hot water.
And theThe sun rises every 4.3 hours in Benue. at the equator, Daytime highs can reach nearly 127°C and nighttime lows can drop to nearly -23°C.
OSIRIS-REx scientists have detected cracks in the rock in spacecraft images from early studies of the asteroid. Delpoe, who with his colleagues measured the length and angles of more than 1,500 fractures in photographs of Osiris Rex, said: Some are shorter than the tennis racket, and some are longer than the court.
Find out fractions Mostly aligned in the northwest and southeast directionindicating that it was caused by the sun, shown here as the main force changing the landscape of Bennu. “If landslides or collisions move rocks faster than they are cracking, the fractures will point in random directions,” Delboe explained.
The scientists used a computer model and measured their fractions Calculate the period between 10,000 and 100,000 years for the thermal fractions of rock multiplication and division. “Thermal fractions in Bennu are quite similar to those we found in Earth and Mars In terms of how it is formed. It’s amazing to see that they can exist and look alike under very strange physical conditions Like low gravity and no atmosphere even compared to Mars.” Christophe Mattontico-author of the article, specializes in Sophia Antipolis in Valbonne, and is also a member of the Observatory of the University of Côte d’Azur in France.
“Bennu’s topography is very young, but the rocks in the asteroids are still billions of years old and contain valuable information about the early solar system.”As he claimed Jason Dworkin, An OSIRIS-REx project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. OSIRIS-REx will return a Bennu sample to Earth at September 24, 2023. “We will be able to learn more details about the age of the surface when we are able to study the sample directly,” Dworkin concluded.
Other analyzes by the same team on data collected when the OSIRIS-REx spacecraft, which collected a sample of the asteroid in October 2020, revealed that The spacecraft would have plunged into Bennu had its rebound engines not activated immediately after picking up dust and rocks on the asteroid’s surface.
The particles that make up the outer surface of the benno They are so loose and tied together so loosely that if someone steps on them, they will feel very little resistance, like stepping into a plastic ball court. “If Bennu is completely compact, that means there are solid rocks, but we found a lot of empty space on the surface,” explained Kevin Walsh, a member of the OSIRIS-REx science team at the San Antonio-based Southwest Research Institute.