NASA’s OSIRIS-REx mission, which recently returned a sample from the asteroid Bennu, has revealed surprising elements that could offer insights into the early solar system. The discovery of magnesium-sodium phosphate in the sample has excited scientists, as it aligns with evidence from other missions and suggests a possible connection to ancient ocean worlds. Detailed analysis of the sample will continue in various laboratories, further uncovering its secrets. Jason Dworkin, a co-author on the paper, emphasizes the significance of these findings for understanding solar system evolution.
A Phosphate Surprise
Analysis of the Bennu sample has revealed unexpected details about the asteroid’s mineral composition. The sample predominantly consists of clay minerals, especially serpentine, which is similar to rock types found at mid-ocean ridges on Earth. This kind of interaction results not only in clay but also in various minerals such as carbonates, iron oxides, and iron sulfides. The biggest surprise, however, was the discovery of water-soluble phosphates, compounds integral to Earth’s biochemistry.
The magnesium-sodium phosphate discovered in the Bennu sample differs from similar findings in JAXA’s Hayabusa2 mission to asteroid Ryugu in 2020. The unique trait of Bennu’s phosphate is its purity and the size of its grains, which are unprecedented among meteorite samples. This raises intriguing questions about the geochemical processes that concentrated these elements on Bennu, hinting at a watery past.
The discovery of these phosphates hints at the historical conditions of Bennu, suggesting it could have splintered off from a small, primitive ocean world. As research continues, scientists hope to further understand how such minerals formed and what they reveal about the early solar system’s environment.
From a Young Solar System
Despite evidence of past water interactions, Bennu remains a chemically primitive asteroid with elemental compositions similar to the Sun. The sample collected by OSIRIS-REx is the largest known repository of unaltered asteroid material on Earth, offering a rare glimpse into the solar system’s early days. These ancient rocks have remained unchanged since their formation, preserving their original state.
The presence of carbon and nitrogen in Bennu’s sample is crucial for decoding the environments where these materials originated. Understanding the chemical processes that facilitated the formation of complex molecules can provide insights into the prebiotic chemistry that may have contributed to the emergence of life on Earth.
What’s Next
In the coming months, NASA’s Johnson Space Center will distribute portions of the Bennu sample to numerous labs for further analysis. As the scientific community delves deeper into these samples, more publications are expected from the OSIRIS-REx Sample Analysis Team, shedding light on the asteroid’s origin and evolution. The continuous study of Bennu will help place critical constraints on the development of Earth-like planets and the intricate processes that shaped our solar system.
The OSIRIS-REx mission, launched in 2016, marks NASA’s first attempt to collect an asteroid sample. After a detailed journey, it successfully transported Bennu’s samples back to Earth in 2023. Further investigations by the international scientific community will deepen our understanding of these extraterrestrial materials, enhancing our knowledge of planetary formation and the potential for life beyond Earth.
NASA’s Goddard Space Flight Center managed the OSIRIS-REx mission, with Dante Lauretta of the University of Arizona serving as the principal investigator. Lockheed Martin Space constructed the spacecraft, while navigation tasks were handled by Goddard and KinetX Aerospace. The mission’s success is attributed to the collaborative efforts of various international partners, including CSA and JAXA.
OSIRIS-REx’s findings not only bring us closer to understanding the origins of our solar system but also offer valuable clues about the potential for life in other parts of the universe. The ongoing studies of Bennu’s samples will continue to provide essential insights, aiding the scientific community in exploring the fundamental questions of planetary science and astrobiology.
