Asteroid samples collected from Bennu by NASA’s OSIRIS-REx mission have revealed fascinating details about the early solar system and the history of water in space.
These samples, the largest ever returned to Earth by an asteroid, are providing scientists with invaluable data on conditions and processes that existed billions of years ago.
Significance of the Bennu Mission and OSIRIS-REx
Nine months after NASA’s OSIRIS-REx mission returned samples from asteroid Bennu, scientists are uncovering surprising details about the asteroid’s past. Bennu was chosen for the mission because of its proximity to Earth, its manageable size, and the presence of organic molecules.
These attributes make Bennu an ideal candidate to study the primordial solar system materials. Returning samples to Earth allows for more comprehensive analysis than can be performed remotely. As stated in Universe Today, “Returning samples to Earth is the best and most complete way to study asteroids.”
Bennu is a B-type asteroid, rich in carbonaceous materials, which are crucial to understanding the early solar system. These materials are essential for tracing the origin and formation of the solar system. Dante Lauretta, principal investigator of The OSIRIS-REx missionexplained the significance: “Bennu may once have been part of a wetter world.”
Analysis of Bennu samples
The samples, weighing around 120 grams, were meticulously analyzed using various advanced techniques, including plasma mass spectrometry, infrared spectrometry and X-ray computed tomography. The results revealed a complex composition of minerals and organic compounds, some of which were unexpected. The pristine nature of these samples means they have not undergone melting and resolidification, preserving their original state from billions of years ago.
One of the most intriguing findings is the presence of serpentine and other clay minerals, similar to those found on Earth’s mid-ocean ridges. These minerals suggest that Bennu may have had interactions with water in its past. Dante Lauretta highlighted the unexpected discovery: “The biggest surprise to me is that there are salty crusts covering a subset of the particles. We are probably quite familiar with this in Arizona. If you have hard water, and you create those white, crusty salts that clog shower heads and faucets, that’s the same kind of process that we’re seeing in these asteroid samples. You had a salty liquid and it evaporated and left behind what we call evaporite minerals.”
Findings and Implications
The discovery of these minerals implies that Bennu may have experienced hydrothermal processes, similar to those on Earth’s ocean floors. This discovery is significant because it suggests that water, a critical ingredient for life, may have been more widespread in the early solar system than previously thought. The presence of these clay minerals on Bennu parallels the processes seen on Earth, providing a fascinating comparison and a deeper understanding of planetary formation and evolution.
Moreover, the presence of water soluble phosphates in the Bennu sample it is particularly important. These compounds are vital components of biochemistry and are found throughout the Earth’s biosphere. Their discovery on Bennu opens new avenues for understanding the distribution of life-sustaining chemicals in the solar system. According to the study published in Meteoritics and Planetary Science, “The presence and condition of phosphates, along with other elements and compounds in Bennu, suggest an aqueous past for the asteroid.”
Research conducted by Dante S. Lauretta and his team has provided a comprehensive overview of the sample, which is now available for other researchers to search and study. “Finally having the opportunity to dig into the OSIRIS-REx sample from Bennu after all these years is incredibly exciting,” Lauretta said in a press release. “This discovery not only answers long-standing questions about the early solar system, but also opens up new avenues of inquiry into the formation of Earth as a habitable planet.”
