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 from an asteroid, are providing scientists with invaluable data on the conditions and processes that existed billions of years ago.
The Significance of Bennu and OSIRIS-REx Mission
Nine months after NASA’s OSIRIS-REx mission returned samples from the asteroid Bennu, scientists are uncovering surprising details about the asteroid’s past. Bennu was chosen for the mission due to its proximity to Earth, manageable size, and the presence of organic molecules.
These attributes make Bennu an ideal candidate for studying the primordial materials of the solar system. Returning samples to Earth allows for more comprehensive analysis than can be conducted 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 for understanding the early solar system. These materials are essential for tracing the solar system’s origin and formation. Dante Lauretta, the principal investigator of the OSIRIS-REx mission, explained the significance: “Bennu potentially could have once been part of a wetter world.”
Analysis of Bennu’s Samples
The samples, weighing about 120 grams, have been meticulously analyzed using various advanced techniques, including plasma mass spectrometry, infrared spectrometry, and X-ray computer tomography. The results have 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 for me is that there are salty crusts coating a subset of the particles. We’re probably pretty familiar with this in Arizona. If you have hard water, and you build up those white, crusty salts that clog your shower head and your faucets, that’s the same kind of process that we’re seeing on these asteroid samples. You had a salty liquid and it evaporated away and left what we call evaporite minerals behind.”
Discoveries and Implications
The discovery of these minerals implies that Bennu might have experienced hydrothermal processes, akin to those on Earth’s ocean floors. This finding is significant as it suggests that water, a critical ingredient for life, might have been more widespread in the early solar system than previously thought. The presence of these clay minerals on Bennu parallels processes seen on Earth, providing a fascinating comparison and a deeper understanding of planetary formation and evolution.
Additionally, the presence of water-soluble phosphates in the Bennu sample is particularly noteworthy. These compounds are vital components of biochemistry and are found throughout Earth’s biosphere. Their discovery on Bennu opens new avenues for understanding the distribution of life-supporting chemicals in the solar system. According to the study published in Meteoritics and Planetary Science, “The presence and state of phosphates, along with other elements and compounds on Bennu, suggest a watery past for the asteroid.”
The 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 request and study. “Finally having the opportunity to delve into the OSIRIS-REx sample from Bennu after all these years is incredibly exciting,” Lauretta said in a press release. “This breakthrough not only answers longstanding questions about the early solar system but also opens new avenues of inquiry into the formation of Earth as a habitable planet.”
Dr. Thomas Hughes is a UK-based scientist and science communicator who makes complex topics accessible to readers. His articles explore breakthroughs in various scientific disciplines, from space exploration to cutting-edge research.
