NASA scientists have confirmed the presence of sugars crucial to life, including ribose and glucose, in samples collected from asteroid Bennu by the OSIRIS-REx mission. This discovery, announced Tuesday, provides compelling evidence that the basic chemical building blocks for life were widespread in the early solar system, suggesting that conditions favorable to life may have existed beyond Earth.
Pristine Extraterrestrial Chemistry
The Bennu samples, sealed in space to avoid contamination, offer an unprecedented look at unaltered extraterrestrial material. Analysis of approximately 600 milligrams of powdered asteroid material revealed not only ribose—a key component of RNA—but also glucose, the primary energy source for life as we know it. This marks the first time glucose has been detected in an extraterrestrial sample.
The presence of ribose is particularly significant, reinforcing the “RNA world” hypothesis, which proposes that RNA preceded DNA as the primary genetic material in early life. The lack of 2-deoxyribose, a sugar used in DNA, further supports this theory. The sugars are believed to have formed over 4.5 billion years ago within Bennu’s parent asteroid, as salty water reacted with organic molecules.
Unexpected Organic Compounds
Beyond sugars, researchers also uncovered an unusual, polymer-like substance dubbed “space gum.” This previously unknown material consists of tangled molecular chains rich in nitrogen and oxygen, and is thought to be an early chemical precursor to life. The material was soft and flexible when it formed, but has since hardened.
Stellar Dust Reveals Bennu’s Origins
Further analysis revealed that Bennu contains six times more dust from ancient exploding stars than any other known space material. This suggests that the asteroid’s parent body formed in a region of the early solar system enriched with stellar debris, providing insights into the conditions present during the formation of planets and life.
“On this primitive asteroid that formed in the early days of the solar system, we’re looking at events near the beginning of the beginning,” said Scott Sandford, an astrophysicist at the Ames Research Center.
These findings strengthen the possibility that similar chemical ingredients were present on other celestial bodies, such as Mars and Europa, raising the prospect of life existing beyond Earth. Scientists are now analyzing samples from asteroid Ryugu, collected by Japan’s Hayabusa2 mission, to determine if similar compounds exist there. The Bennu discoveries provide a vital new understanding of the early solar system and the potential for life’s origins in the universe.
