Chemical components essential for life have been detected in the dusty residue of an asteroid named Bennu, according to an analysis. Samples obtained from this celestial body, collected by a Nasa spacecraft and returned to Earth, contain a diverse range of minerals and thousands of organic compounds. These include amino acids, the building blocks of proteins, and nucleobases, crucial elements of DNA.
While this discovery does not imply the presence of life on Bennu, it supports the idea that asteroids may have transported these vital materials to Earth during collisions billions of years ago. Scientists conjecture that similar compounds could have been distributed to other planets within our Solar System.
Prof Sara Russell, a cosmic mineralogist from the Natural History Museum in London, remarked, "What we've learned from it is amazing. It's telling us about our own origins, and it enables us to answer these really, really big questions about where life began. And who doesn't want to know about how life started?"
The findings have been detailed in two papers published in the journal Nature. Capturing a portion of Bennu has been one of Nasa's boldest missions to date. The Osiris Rex spacecraft deployed a robotic arm to gather material from the 500-meter-wide space rock, returning it to Earth in 2023.
Approximately 120 grams of black dust were collected and distributed to researchers globally, revealing valuable insights. Prof Russell stated, "Every grain is telling us something new about Bennu." An ounce of the asteroid was sent to specialists in the UK for further examination.
The recent research has unveiled a wealth of nitrogen and carbon-rich compounds within the space rock, including crucial amino acids and DNA components. The presence of minerals and salts indicates past water activity on the asteroid. Compounds essential for biochemical reactions, like ammonia, were also identified.
This study suggests that asteroids like Bennu may have delivered water and organic substances to Earth during its early history, fostering the conditions for life to emerge. Dr. Ashley King from the Natural History Museum explained, "Earth is unique, in that it's the only place where we have found life so far, but we know asteroids were delivering those ingredients, the carbon and the water, throughout the Solar System."
As scientists explore the implications of these findings, they continue to investigate the origins of life on Earth and the potential for discovering life elsewhere in our Solar System.