” We were surprised to learn that the aging and weathering process on asteroids occurs so quickly, geologically speaking.”– Marco Delbo
This mosaic of asteroid Bennu was developed utilizing observations made by NASAs OSIRIS-REx spacecraft that remained in close distance to the asteroid for over two years. Credit: NASA/Goddard/University of Arizona
Recently, researchers from NASAs OSIRIS-REx mission found that surface area regrowth takes place on asteroids far more rapidly than in the world. By examining high-resolution images of rock fractures on asteroid Bennu taken by the OSIRIS-REx spacecraft, the scientists discovered that the Suns heat fractures rocks on Bennu in just 10,000 to 100,000 years. With the usage of this knowledge, scientists will be able to much better forecast the time it takes stones on asteroids like Bennu to fragment into smaller pieces, a few of which might eject into space while others may stay on the asteroids surface.
Although 10s of countless years might sound quite slow, “we believed surface regeneration on asteroids took a couple of millions of years,” said Marco Delbo, senior scientist at Université Côte dAzur, CNRS, Observatoire de la Côte dAzur, Laboratoire Lagrange, Nice, France, and lead author of a paper published in June 2022 in the journal Nature Geoscience. “We were surprised to discover that the aging and weathering process on asteroids occurs so rapidly, geologically speaking.”
Over millions of years, temperature, wind, and water changes slowly erode rock to develop brand-new surfaces. If you hiked into the Grand Canyon, you would see unique rock layers; the leading layers tend to be the youngest rocks, dating around 270 million years old, and the layers at the bottom of the canyon are the earliest, about 1.8 billion years old.
The PolyCam aboard NASAs OSIRIS-REx spacecraft offered high-resolution, microscope-like pictures of asteroid Bennus surface area. This made it possible for scientists to map more than 1,500 rock fractures. Credit: NASA/Goddard/University of Arizona
Quick temperature changes on asteroid Bennu produce internal stress that fractures and breaks down rocks, equivalent to how a cold glass breaks under warm water. On Bennu, the Sun rises every 4.3 hours. At the equator, daytime highs can reach practically 260 ° F( about 127 ° C), and nighttime lows plunge to nearly minus 10 ° F( about minus 23 ° C).
OSIRIS-REx scientists found cracks in the rocks in spacecraft images from the first surveys of the asteroid. All of the fractures seemed to point in the very same direction, “a distinct signature that temperature shocks in between the night and the day might be the cause,” said Delbo.
Same image as above, however with the fractures highlighted in red. Credit: NASA/Goddard/University of Arizona
Delbo and his coworkers determined the length and angles of more than 1,500 fractures in OSIRIS-REx images by hand: some much shorter than a tennis racket, others longer than a tennis court. They discovered the fractures predominantly line up in the northwest-southeast instructions, suggesting they were brought on by the Sun, which is revealed here to be the main force changing Bennus landscape.
Just recently, researchers from NASAs OSIRIS-REx objective found that surface area regrowth takes place on asteroids far more rapidly than on Earth. By examining high-resolution images of rock fractures on asteroid Bennu taken by the OSIRIS-REx spacecraft, the scientists discovered that the Suns heat fractures rocks on Bennu in only 10,000 to 100,000 years. With the usage of this knowledge, researchers will be able to much better forecast the time it takes stones on asteroids like Bennu to fragment into smaller sized pieces, some of which might eject into area while others might remain on the asteroids surface.
The PolyCam aboard NASAs OSIRIS-REx spacecraft provided high-resolution, microscope-like images of asteroid Bennus surface. Fast temperature level modifications on asteroid Bennu create internal stress that breaks and fractures down rocks, equivalent to how a cold glass breaks under hot water.
” If impacts or landslides were moving stones quicker than the boulders were breaking, the fractures would point in random instructions,” stated Delbo.
The research team used a computer design and their fracture measurements to determine the 10,000- to 100,000-year timeframe for thermal fractures to propagate and divide rocks.
” The thermal fractures on Bennu are quite comparable to what we find in the world and on Mars in terms of how they form,” stated Christophe Matonti, a co-author of the paper at Université Côte dAzur, CNRS, Observatoire de la Côte dAzur, Géoazur, Sophia-Antipolis, Valbonne, France. “It is interesting to see that they can exist and are comparable in extremely unique physical conditions [low gravity, no atmosphere], even compared to Mars.”
” Keep in mind, the topography of Bennu is young, but the rocks on the asteroids are still billions of years of ages and hold valuable information about the start of the planetary system,” stated Jason Dworkin, OSIRIS-REx task scientist at NASAs Goddard Space Flight Center in Greenbelt, Maryland.
OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer) will return a sample from Bennu to Earth on September 24, 2023. “We will have the ability to discover more information about the age of the surface when we are able to directly study the sample,” said Dworkin.
Reference: “Alignment of fractures on Bennus boulders indicative of rapid asteroid surface development” by Marco Delbo, Kevin J. Walsh, Christophe Matonti, Justin Wilkerson, Maurizio Pajola, Manar M. Al Asad, Chrysa Avdellidou, Ronald-Louis Ballouz, Carina A. Bennett, Harold C. Connolly Jr., Daniella N. DellaGiustina, Dathon R. Golish, Jamie L. Molaro, Bashar Rizk, Stephen R. Schwartz and Dante S. Lauretta, 23 May 2022, Nature Geoscience.DOI: 10.1038/ s41561-022-00940-3.
By Rani C. Gran, NASAs Goddard Space Flight
July 24, 2022