NASA’s OSIRIS-REx mission brought back pristine pieces of the asteroid Bennu in 2023—and these tiny grains are turning out to be a treasure chest of clues about how the solar system formed and how life’s ingredients first appeared on Earth.
Three new studies published in Nature Geoscience and Nature Astronomy describe astonishing discoveries inside these samples: essential sugars, a strange gum-like substance never seen before in space materials, and an unusually large amount of dust from ancient exploding stars.
Life’s sugars found in asteroid dust
In one study, scientists led by Yoshihiro Furukawa of Tohoku University found two important sugars inside Bennu’s material: ribose and, for the first time in extraterrestrial samples, glucose.
These sugars are not evidence of life, but they are key building blocks for life as we know it.
Ribose is especially important. It forms the backbone of RNA, a molecule essential for storing information and performing chemical reactions inside every cell.
Remarkably, Bennu contains every ingredient needed to assemble RNA—ribose, nucleobases, and phosphate—suggesting that the basic components of life were widespread in the early solar system.
Intriguingly, researchers did not find deoxyribose, the sugar in DNA. This supports the “RNA world” hypothesis, which proposes that before DNA and proteins existed, early life may have relied mainly on RNA. Bennu’s chemistry hints that ribose may have been more abundant than deoxyribose in the environments where the first biological molecules formed.
A mysterious “space gum” preserved for billions of years
A second discovery stunned researchers: a flexible, gum-like material never seen in any meteorite or asteroid sample before.
Led by Scott Sandford (NASA Ames) and Zack Gainsforth (UC Berkeley), the research team found this strange substance inside carbon-rich grains.
The material once behaved like soft gum or plastic, bending when touched and dimpling under pressure. Over time, exposure to radiation hardened it, much like plastic furniture left out in the sun.
Chemically, the material is made of complex polymers loaded with nitrogen and oxygen. On Earth, its chemical groups resemble those found in polyurethane—but this “space plastic” is much more chaotic and irregular.
Scientists believe it formed billions of years ago inside Bennu’s parent asteroid as minerals and ices slowly warmed.
A compound called carbamate may have reacted and polymerized before liquid water was present, creating this ancient gum-like material. Its survival offers an incredibly rare look at one of the earliest chemical processes to occur in the solar system.
A surprisingly rich supply of stardust from ancient supernovas
A third study led by Ann Nguyen (NASA Johnson Space Center) analyzed microscopic “presolar grains”—tiny fragments older than our solar system. These grains formed in massive stars and supernovas long before the sun was born.
Bennu’s samples contain six times more supernova dust than any previously studied space material. This suggests Bennu’s parent asteroid formed in a part of the early solar system rich in the debris of exploding stars.
Although Bennu’s parent asteroid was heavily altered by warm water over time, some fragments inside the samples remained untouched. These pockets preserved fragile organic molecules and ancient stardust, giving scientists a window into the earliest raw materials from which our solar system was built.
A time capsule of life’s ingredients
Combined, these discoveries paint an extraordinary picture: Bennu’s building blocks contain sugars important for life, complex polymers that may have helped early chemistry flourish, and stardust older than the sun.
As scientists continue studying the OSIRIS-REx samples, they are uncovering how the earliest ingredients of life may have formed, survived, and been transported across the young solar system—possibly even to early Earth.
Source: NASA.
