Scientists have identified essential ingredients for life in samples collected from the asteroid Bennu. This discovery supports the theory that asteroids may have delivered the fundamental components necessary for life to emerge on Earth and potentially other celestial bodies. The pristine fragments, returned to Earth by NASA’s OSIRIS-REx mission in 2023, contain several sugars critical for biological processes, including ribose, a vital component of RNA.
The recent findings finalize the inventory of key life-forming compounds previously detected within the Bennu samples. Earlier analyses confirmed the presence of water, carbon, amino acids, and phosphates. Most notably, all five nucleobases comprising DNA and RNA had been identified, but the sugar essential for forming the backbone of these genetic molecules was missing—until now.
Asteroid Samples Provide New Insights
Lead researcher Yoshihiro Furukawa from Tohoku University stated, “These sugars complete the inventory of ingredients crucial to life.” He added that the findings suggest asteroids “really could have delivered all the ingredients necessary for life to Earth or to other bodies in the solar system, like Mars.” Furukawa’s team analyzed a small portion of the sample, revealing not only ribose but also other sugars, such as glucose, which is essential for the metabolism of nearly all life forms on Earth.
The prevailing scientific theory posits that these sugars originated from chemical reactions in briny water on Bennu’s much larger parent asteroid over 4.5 billion years ago. The OSIRIS-REx spacecraft collected and sealed these samples in space, ensuring they remained uncontaminated by Earth’s environment. This preservation offers scientists a rare chance to study untouched extraterrestrial chemistry.
While similar compounds have been found in meteorites that landed on Earth, there was always concern regarding potential contamination. Furukawa noted, “This finding in the Bennu sample guarantees that these results were true.” The team published their findings on October 3, 2023, in the journal Nature Geoscience.
Implications for the Origin of Life
The discovery of ribose, alongside the absence of 2-deoxyribose (the sugar component of DNA), strongly supports the “RNA world” hypothesis. This theory suggests that the earliest life forms on Earth were based on RNA, which had the capacity to store genetic information and replicate, with DNA evolving at a later stage.
Astrobiologist Danny Glavin from NASA’s Goddard Space Flight Center and a co-investigator on the OSIRIS-REx mission, expressed optimism regarding the implications of these findings. He explained that if these materials were widespread throughout the early solar system, other locations such as Jupiter’s icy moon Europa may also have been seeded with similar raw ingredients. Glavin stated in a NASA video announcing the findings, “I’m becoming much more optimistic that we may be able to find life beyond Earth, even in our own solar system.”
The implications of this research extend beyond mere scientific curiosity; they open new avenues for understanding the origins of life and the potential for its existence elsewhere in the cosmos. As researchers continue to analyze the Bennu samples, they remain hopeful that these discoveries will illuminate the complex processes that gave rise to life on our planet and possibly beyond.
