January 28, 20256 min readAsteroid Bennu Is Packed with Lifes Building Blocks, New Studies ConfirmMaterial retrieved from the asteroid Bennu by NASAs OSIRIS-REx spacecraft shows that all the basic building blocks of life were astonishingly widespread in the early solar systemBy Mike Zeitz edited by Lee BillingsA view of the OSIRIS-REx sample canister, containing material from asteroid Bennu, at NASAs Johnson Space Center. NASA/Alamy Live News via DigitaleyeThe deserts of Utah are notorious for supposed alien visitations, but a real extraterrestrial emissary that parachuted to a soft landing there in September 2023 is proving more impactful. Onboard the truck-tire-size capsule from space was invaluable cargo: more than 120 grams of pristine material from the solar systems early history. Three years earlier NASAs OSIRIS-REx spacecraft had grabbed these samples from the surface of the asteroid Bennu for their fateful delivery to Earth. The hope was that the coal-black material would help reveal how the solar systemand with it, Earth and our planets lifeformed. Soon after the Bennu samples recovery, teams of scientists began to eagerly analyze them in highly specialized laboratories.The breathtaking preliminary results from that work, teased early last year, have now become more detailed and definitive, confirming the enormous scientific value of the samples. Two studies published on January 29, 2025, show that even in dark, cold regions of the early solar system, astonishingly diverse chemical processes gave rise to numerous building blocks of life.At that time, more than 4.5 billion years ago, countless celestial bodies orbiting the newborn sun repeatedly collided in a chaotic game of primordial billiards, at turns smashing on another to smithereens or clumping together into larger objects. Bennu was somewhere in the mixa rubble pile ejected from a larger celestial body that at some point fell victim to a massive impact. But signs of this nameless progenitor survived on Bennuraw material from the solar systems youth, preserved in the cold of space.On supporting science journalismIf you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.Bennus parent body apparently contained plenty of water, as described in a paper appearing in the journal Nature. Some of the water evaporated and left behind a salty brine. According to an accompanying paper published in Nature Astronomy, this brine contained thousands of organic compounds, including 14 of the 20 amino acids found in terrestrial organisms, as well as all the nucleotide bases that make up our DNA and RNA. This means that the basic molecules of life existed in our solar system practically from the start.Tim McCoy, co-lead author of the Nature study and a meteorite expert at the Smithsonian National Museum of Natural History, was already involved in the initial analyses of the Bennu samples that began shortly after their arrival on Earth. Numerous minerals revealed in those first looks are now no longer so mysterious; they were clearly found to be residues of evaporated water deposits.The original celestial body from which Bennu came was probably not covered by oceans like Earth is, however. It was certainly a wet world, McCoy says, but it was probably more likely a ... muddy world than one that had oceans on or below its surface. According to McCoy, the water deposits were probably short-lived and only a few meters thick. That is not to say that this reduces their epochal implications: The discovery of clays, phosphates, salts and evidence for an ancient, sodium-rich brine show not only that the ingredients for the first steps toward life were present but also that a promising environment was there for such steps, McCoy says.How closely did the salty brine on Bennus parent body resemble the primordial soup that simmered on the young, watery Earth and perhaps cooked up the first terrestrial life? This was the question addressed by the Nature Astronomy study, co-led by Daniel Glavin, a NASA scientist and lead of OSIRIS-RExs organics analysis team, which includes some members from around the world. Searching for organic compounds in the sample material from Bennu, he and his colleagues found the majority of the amino acids and all the nucleotide bases necessary for life on Earth. Such compounds have been identified in meteorites that fell to our planet before, Glavin explains, but unlike those cases, the samples from Bennu were protected from terrestrial contamination and the infernal heat of a high-speed plunge through Earths atmosphere.According to some theories, the chemical precursors of early life on Earth were imported via asteroids rather than being home-brewed. Glavin sees the discovery of the organic molecules as strengthening these ideas. Indeed, he says, this conclusive proof that so many of lifes molecular building blocks were so widespread in the early solar system has increased the chances that life could have started elsewhere beyond Earth.Analyses of the precious OSIRIS-REx samples from Bennu are ongoing and use a wide variety of modern methods in laboratories around the world. One of these is the Schwiete Cosmochemistry Laboratory at Goethe University Frankfurt in Germany, which boasts a powerful transmission electron microscope (TEM) that can be used to examine the finest structures with great precision. It is the only TEM laboratory outside the U.S. to have received a small amount of the Bennu sample for this purpose. TEM is especially useful for studies involving water-rock interaction, as much of that information is recorded on the nanoscale, says Sheri Singerling, a researcher at Goethe University Frankfurt and a co-author of the Nature study. Even so, she emphasizes that her work only provides one piece of the puzzle: The more eyes we can have on these samples from researchers with different expertise, the better, Singerling says.Altogether, studies of the samples are sketching out a curious, still incomplete picture of Bennus mysterious parent body. Compared with the asteroid, which formed from many shattered fragments, its parent body was larger and more dense, Singerling concludes. When massive impacts blasted what would become Bennu into space, this parent body would have also lost volatile components such as liquids while presumably excavating some material from its depths. In Bennu, such debris apparently came together. When we look at Bennus surface and near-surface today, we could be looking at materials that formed well within the parent body, Singerling says.Bennu now orbits the sun at a distance close to that of Earths, but the original celestial body must have formed much farther out. But how far? Certain features that are common in meteorites, such as chondrules or calcium and aluminum-rich inclusions, are missing, Singerling explains. Such structures form at high temperatures, especially near the sun. This, as well as the isotopes and organic substances in Bennu, all point toward an outer solar system origin for its parent body, she adds. McCoy also locates Bennus origin in those far-flung frigid hinterlands. It would certainly have had to form where ice was stable, he says, so likely [at] the current position of Jupiter or beyond. The abundant presence of volatile ammonia in the samples is also further evidence of [Bennus origin] in the cold, outer regions of our solar system.Besides being so free of contaminants and so closely associated with a specific known source, the samples from Bennu are unusual in another important way, Singerling explains: We now have the results of two missions to primitive carbon-rich celestial bodies: Hayabusa2 to the asteroid Ryugu and OSIRIS-REx to Bennu, she says. The Japanese probe Hayabusa2 brought nearly 5.5 grams of asteroid material to Earth in 2020. Both of these missions samples are remarkably similar to each other and most closely resemble material found in meteorites called CI chondrites. These are exceedingly rare in meteorite collections on Earth, Singerling says, in part because CI chondrites are so delicate that they typically dont endure the fiery ride through Earths atmosphere. This tells us our collections are biased and that these types of samples are more common in space than what is retrieved on Earth, Singerling concludes. This, she and others say, is another reason why asteroid-sample-return missions are indispensable.And more surprises from OSIRIS-RExs haul may be in store. We are still at the very early stages of the analysis of the Bennu samples, Glavin says. His team is currently examining a much larger sample from the asteroid that weighs around six gramsenough material to discern other, as-yet-unseen organic molecules that may be present in smaller quantities, such as sugars, peptides and perhaps even nucleotides similar to [those in] DNA and RNA. Glavins goal is to get a more precise idea of how the organic molecules formed in Bennus parent body.On the one hand, such studies paint a more detailed picture of how the molecules so crucial for lifes genesis grew in the early solar system. On the other, they show where the right conditions for that growth existed. And it can already be said that such conditions seem to have occurred much more frequently than previously thought far beyond Earth. For McCoy, the biggest open question is therefore how this ancient brine compares with modern brines that exist today on icy bodies of the outer solar system, like Saturns moon Enceladus. In other words, are lifes building blocks still abundant in our planetary neighborhood, and have they sparked lifes second genesis under favorable conditions elsewhere in the solar system? That question wont be answered until we visit these places with instruments that can take samples, McCoy says.Scientists will be studying these small pieces from Bennu for many years to come, undoubtedly gaining further insights into the history of the solar systemand perhaps even of life itself. But it is equally clear that much will only be revealed with new missions to other celestial bodies. Every finding generates more questions, Singerling says. Thats the beauty of science and its never-ending search for answers.This article originally appeared in Spektrum der Wissenschaft and was reproduced with permission.