Bennu unboxing shows ancient asteroid holds carbon and water

Just some building blocks for life – in a few billion years, who knows what could develop?

Initial analyses of samples collected from the surface of Bennu reveal the ancient asteroid contains water and carbon-based molecules, vital materials needed to create and support life.

"As we peer into the ancient secrets preserved within the dust and rocks of asteroid Bennu, we are unlocking a time capsule that offers us profound insights into the origins of our solar system," explained Dante Lauretta, OSIRIS-REx principal investigator and a professor of planetary science and cosmochemistry at the University of Arizona, on Wednesday.

OSIRIS-REx being the spacecraft NASA sent out to collect a sample from the asteroid and bring that material to Earth for study.

"The bounty of carbon-rich material and the abundant presence of water-bearing clay minerals are just the tip of the cosmic iceberg," Lauretta continued.

With each revelation from Bennu, we draw closer to unraveling the mysteries of our cosmic heritage

"These discoveries, made possible through years of dedicated collaboration and cutting-edge science, propel us on a journey to understand not only our celestial neighborhood but also the potential for life's beginnings. With each revelation from Bennu, we draw closer to unraveling the mysteries of our cosmic heritage."

Last month, OSIRIS-REx returned from its seven-year mission with 4.5-billion-year-old regolith it snatched from the surface of Bennu. Now, scientists are in the process of carefully examining not just the contents of the probe's Touch-and-Go Sample Acquisition Mechanism (TAGSAM) but also the dirt on it, also from the asteroid.

In that exterior material, they found signs the asteroid is made up of carbon and a surprising amount of water, suggesting it carries the vital ingredients needed for life to form. Astronomers believe asteroids like Bennu may have crashed into Earth and delivered the necessary building blocks for life to begin on our planet, also known as the panspermia hypothesis.

"We can use the hydrogen isotopic compositions of hydrated minerals (e.g., clays) in planetary materials, such as the Bennu samples, as tracers of their origins and potential link(s) to water on other planetary bodies, "Pierre Haenecour, assistant professor at the University of Arizona's Lunar & Planetary Laboratory, who is working to analyze the OSIRIS-REX return sample, told The Register.

"There were times in the early history of the Earth when there were a lot more asteroid impacts, and it is those impacts that contributed to progressively increase the amount of water on our planet. We know from the study of meteorites that both water-rich minerals and carbonaceous compounds can survive atmospheric entry and impact on the Earth. We find them in carbonaceous chondrites, such as the Tarda meteorite that fell in Morocco on August 25, 2020."

Over billions of years asteroids could have brought Earth water and organic matter needed to form molecules such as DNA, the genetic material present in nearly all living organisms, for example. NASA believes it could be one step closer to cracking the mystery of the origin of life, thanks to OSIRIS-REx's sample return.

"The OSIRIS-REx sample is the biggest carbon-rich asteroid sample ever delivered to Earth and will help scientists investigate the origins of life on our own planet for generations to come," NASA Administrator Bill Nelson commented.

"Almost everything we do at NASA seeks to answer questions about who we are and where we come from. NASA missions like OSIRIS-REx will improve our understanding of asteroids that could threaten Earth while giving us a glimpse into what lies beyond. The sample has made it back to Earth, but there is still so much science to come – science like we've never seen before." 

NASA is still analyzing the dust on the outside of the TAGSAM device, which was picked up in the process of collecting the asteroid sample and storing it in internal canisters. A quick analysis of the material was conducted within the first two weeks after the capsule touched down in the Utah desert. The experiments looked at the chemical composition of Bennu, and snapped close-up images of its particles to study its shape and interior, including making 3D scans of some particles. 

More detailed analyses need to be performed to study Bennu and understand its role in helping shape the Solar System and life on Earth. NASA will keep 70 percent of the OSIRIS-REx sample, and share the rest of the contents with over 200 scientists around the world. Some of the dust will also be kept for displays at the Smithsonian Institution, Space Center Houston, and the University of Arizona. ®

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