Astronomers due to the interplanetary station OSIRIS-REx have confirmed the idea that thermal weathering is one of the main processes responsible for the evolution of the body surface devoid of atmosphere. They managed to find signs of delamination, cracking and fracture of boulders and rocks on the surface of asteroid Bennu, which are caused by temperature changes. Article published in the journal Nature.
Weathering is one of the main geomorphologic processes that are responsible for creating various landforms on the planet. Scholars have identified several mechanisms of weathering, which are associated with different factors, for example, internal stresses in the rocks due to temperature extremes (heat stress). The effects of such weathering on the Earth, such as the stratification of the surface boulders in the desert, well studied, however, about how such a process goes on small bodies, satellites or planets of the Solar system, almost nothing is known. Modeling and research in terrestrial laboratories showthat thermal weathering may play a huge role in the formation of the relief on the bodies devoid of atmosphere, and be responsible for the creation of regolith and cracking boulders on the moon and Mars, but to fully appreciate the contribution of this process to the evolution of the surface bodies of the Solar system is difficult because of the lack of observational data.
A team of astronomers headed by Jamie Molaro (Jamie Molaro) from the Planetological Institute of the USA published the results of a detailed analysis of the images of the surface of near-earth asteroid (101955) Bennuobtained by on-Board OCAMS interplanetary station OSIRIS-REx, which is already more than a year exploring the asteroid from orbit. Scientists looking for signs of thermal weathering on the many boulders and rocks covering the surface of Bennu to understand how this process affects the structure of the rocks on the asteroid, on which day the temperature can reach 127 degrees Celsius, and at night drops to -73 degrees Celsius.