Asteroid Bennu holds clues to life’s cosmic origins, NASA finds
The findings suggest Bennu’s parent body once held liquid water, shedding light on cosmic processes that may have contributed to life on early Earth
Asteroid Bennu, once thought a lifeless relic, has surprised scientists with briny traces of life's raw ingredients.
Samples collected by NASA's OSIRIS-REx mission reveal not only water marks from Bennu's past but also a salty residue packed with compounds vital for biology — including amino acids and RNA/DNA building blocks.
Two studies in Nature and Nature Astronomy journals detail the findings. The asteroid's brine, rich in phosphorus and sodium carbonate, differs distinctly from Earth's. Crucially, the samples — collected from Bennu in 2020 as it floated 200 million miles away — remain untouched by our planet's chemistry, offering a rare glimpse into space's primordial soup.
"We now know from Bennu that the raw ingredients of life were combining in really interesting and complex ways on Bennu's parent body," said Tim McCoy, co-author of the Nature study. The mission scooped up 121.6 grams of material — over twice NASA's target — an ample supply to the labs to probe our solar system's history.
Bennu, a 4.5-billion-year-old fragment of a larger asteroid, likely once held liquid water. As this water vanished, it left behind crusty minerals now hinting at cosmic processes that may have seeded life.
The discovery fuels hopes that asteroids delivered life's blueprints to early Earth. Unlike meteorites, which burn through our atmosphere, Bennu's pristine chunks avoid contamination.
In 2023, experts flagged Bennu as a game-changer for astrobiology. Now, with fresh proof of its chemical richness, the asteroid is living up to the hype.