Scientists have discovered all of the essential ingredients for life in samples collected from the asteroid Bennu, bolstering the theory that asteroids could have delivered the necessary components for life to begin on Earth — and possibly elsewhere.

Pristine fragments of the asteroid, delivered to Earth by NASA’s OSIRIS-REx mission in 2023, were found to contain several sugars essential for biology, including ribose, a crucial building block of RNA. The new discovery completes the inventory of key life-forming compounds found within the asteroid material.

Previous analyses of the Bennu samples, extracted directly from the asteroid hundreds of millions of miles away, had already confirmed the presence of water, carbon, amino acids, and phosphates. More recently, all five of the nucleobases that make up DNA and RNA were also detected. 

However, the sugar component needed to form the backbone of these genetic molecules remained missing — until now. “These sugars complete the inventory of ingredients crucial to life,” said lead researcher Yoshihiro Furukawa of Tohoku University in Japan.

The new work shows that asteroids “really could have delivered all the ingredients necessary for life to Earth or to other bodies in the solar system, like Mars,” Mr. Furukawa noted.

The team led by Mr. Furukawa analyzed a small portion of the sample, revealing the presence of not only ribose but also other sugars like glucose, which is vital for the metabolism of nearly all life on Earth. The prevailing scientific theory is that these sugars formed from chemical reactions in briny water on Bennu’s much larger parent asteroid more than 4.5 billion years ago. 

Because the OSIRIS-REx spacecraft collected and sealed the samples in space, they remained uncontaminated by Earth’s environment. This has allowed scientists an unprecedented opportunity to study pristine extraterrestrial chemistry. While similar compounds have been detected in meteorites that have crashed on Earth, there was always a concern of earthly contamination.

“This finding in the Bennu sample guarantees that these results were true,” Mr. Furukawa, whose team’s findings were published Tuesday in the journal Nature Geoscience.

The discovery has significant implications for the origin of life. The presence of ribose but not 2-deoxyribose (the sugar in DNA) strongly supports the “RNA world” hypothesis. This idea suggests that the earliest life forms on Earth were based on RNA, which could both store genetic information and replicate, with DNA evolving later.

An astrobiologist at NASA’s Goddard Space Flight Center and a co-investigator on the mission, Danny Glavin, shared this optimism. He explained that if these materials were widespread throughout the early solar system, then places like Mars or Jupiter’s icy moon Europa may also have been seeded with the same raw ingredients.

“I’m becoming much more optimistic that we may be able to find life beyond Earth, even in our own solar system,” Mr. Glavin said in a NASA video announcing the findings.