Michelle Thompson, a Purdue planetary scientist, recently analyzed samples from asteroid Bennu. These samples contain clues about the origins of life and how Earth acquired water. (Purdue University photo/Rebecca Robiños)
Scientists have discovered some astonishing things in just 4 ounces of material from asteroid Bennu. The samples, brought to Earth in 2023, seem to hold the building blocks of life and hints about the origins of Earth’s water.
Michelle Thompson, an associate professor at Purdue University, was among the first to study these samples. As part of a team of scientists, Thompson had 72 hours to make preliminary assessments after the samples arrived from NASA’s OSIRIS-REx spacecraft.
Thompson’s research focuses on how space rocks interact with their environments. She emphasized that Bennu’s samples provide insights into our solar system’s early days, including what Earth was made of and what might have led to life.
“Asteroids are like time capsules,” she said. “Studying them helps us understand the origins of our solar system and life itself.”
The research results were published in the journal Nature, showcasing the significant findings from the initial analysis phase.
NASA’s OSIRIS-REx mission took over a decade to complete. Launched in 2016, it collected samples from Bennu and returned them to Earth. This mission aims to shed light on the formation of Earth and other planets in the solar system.
“This is a once-in-a-lifetime opportunity for me,” Thompson said, reflecting on the mission that began when she started her graduate studies.
The OSIRIS-REx mission returned a canister containing 4.29 ounces (121.6 grams) of Bennu’s material. This is about the same weight as a medium apple or a stick of butter. While meteorites can fall to Earth naturally, they often don’t survive the journey intact, and it’s difficult to study them without contamination from our planet’s environment. The pristine samples from OSIRIS-REx allowed for a clearer analysis of their original state.
Bennu is a carbon-rich asteroid, meaning it contains carbon—an essential element for life. These asteroids can be dark and hard to study from Earth, but now, a team of 66 scientists has examined the minerals found in the Bennu samples. They discovered a significant amount of phosphate and sulfate minerals, which are vital for life on our planet. The presence of these minerals suggests that Bennu may have once hosted an ancient salt lake, an environment that could have sparked the chemistry needed for life.
Thompson noted that by studying organic molecules in Bennu’s samples, researchers hope to understand what might have seeded life on Earth. “We’re not finding life itself, but we’re looking at the essential components that could have led to life,” she explained.
Additionally, researchers are examining how much water was in Bennu’s minerals. This could help us understand how much water was available in the early solar system, potentially delivered through impacts over time. Comparisons with other celestial bodies suggest that essential components for life could be widespread across the solar system.
