NASA’s OSIRIS-REx mission has made an exciting discovery that could change how we think about the origins of life. A tiny rock sample from asteroid Bennu holds traces of tryptophan, a complex amino acid rarely seen in outer space. This finding is remarkable because it’s the first time tryptophan has been detected in any asteroid sample, suggesting that the building blocks of life might have come to Earth from space.
This discovery is highlighted in a recent study published in the journal PNAS. Researchers believe that if complex amino acids like tryptophan can form in space, then the ingredients for life might be more common across the universe than we thought.
Why This Discovery Matters
Tryptophan is one of the 20 amino acids essential for all known life forms. Until this finding, scientists didn’t believe that such a complex molecule could form in the harsh conditions of space. José Aponte, an astrochemist at NASA, emphasized the significance of this breakthrough: “Finding tryptophan in the Bennu asteroid is a big deal.”
Researchers analyzed just 50 milligrams of Bennu material, smaller than a fingernail, yet it contains extraordinary insights. Unlike meteorites that are burned during atmospheric entry, Bennu’s sample arrived on Earth in pristine condition. Dante Lauretta, a planetary scientist, pointed out that this purity allows scientists to examine the original chemical makeup of the early solar system—more than 4.5 billion years ago.
A Look Back in Time
Bennu is thought to have originated from a larger parent body in the asteroid belt between Mars and Jupiter about 2 billion years ago. It has been circling near Earth for almost 1.75 million years, serving as a “time capsule.” The discovery of tryptophan adds to the 15 amino acids already found on Bennu, showing that its chemistry might resemble the early Earth more closely than we imagined.
These findings support a growing theory: asteroids could have been responsible for delivering life’s essential ingredients to our planet. This idea is backed up by past missions like Japan’s Hayabusa2, which also discovered amino acids on asteroid Ryugu.
Building Life’s Ingredients
Angel Mojarro, an organic geochemist and lead author of the new study, likened organic molecules found on Bennu to jigsaw pieces. He said, “What this is telling us is that many of the building blocks of life can be produced naturally within asteroids or comets.” Scientists now believe these molecules may have formed long before our solar system began, sparked into existence by ancient stars in their fiery deaths.
This fresh perspective challenges the notion that life arose solely from Earth’s conditions. Instead, it suggests that some essential ingredients might have arrived pre-packaged by space rocks.
For more on this exciting find, visit PNAS.
