The Summary
- A NASA spacecraft brought samples from the asteroid Bennu back to Earth in 2023.
- The first in-depth analyses of that material have revealed organic molecules, including building blocks of life.
- The results bolster the theory that asteroids that crashed into Earth may have delivered the ingredients for life.
Scientists have found a variety of organic chemicals, including essential components of life, in samples collected from a far-off asteroid.
The unexpected discovery raises the possibility that the chemical components required for life were present across the early solar system.
Launched in 2016, NASA’s OSIRIS-REx mission collected dust, silt, and rock fragments from the asteroid Bennu and transported them to Earth in 2023. It is estimated that the 4.5-billion-year-old asteroid formed during the first 10 million years of the solar system’s existence.
The samples contained 14 of the 20 amino acids that life on Earth requires to make proteins, as well as thousands of chemical compounds, according to an examination of that asteroid material that was published on Wednesday in the journal Nature. Four nucleobases, the primary building blocks of DNA and RNA that store and transfer genetic blueprints within human cells, were also present in the samples.
The findings support the hypothesis that asteroids that struck Earth when it was young would have brought the elements needed for life to establish themselves, even if the researchers did not discover any proof of life on Bennu. The results may also indicate that there may be a greater likelihood of life forming on other planets and moons in the solar system than previously believed.
Nicky Fox, the associate administrator of NASA’s Science Mission Directorate, stated in a news briefing on Wednesday that the OSIRIS-REx mission is already changing the textbook on what we know about the components believed to be required for the development of life in our solar system.
Amino acids and other similar organic components had previously been found in meteorites, but since these pieces of space rock are examined after undergoing ferocious journeys through Earth’s atmosphere, they are not perfect samples.
Directly collecting samples from an asteroid in orbit is like looking into a time capsule from the early solar system, but meteorites have been exposed to and affected by conditions on Earth that could bias scientific results.
The pristine nature of those materials is what makes the OSIRIS-REx Bennu discovery so important, according to astrobiologist Danny Glavin of NASA’s Goddard Space Flight Center.
According to Glavin, the Bennu samples were protected from adverse conditions during atmospheric re-entry by the return canister that transported them.
In summary, he stated: “We are more certain that the organic material we are observing in these samples is alien and not contamination.” These results are reliable.
The researchers discovered a few surprises in the Bennu samples. According to Glavin, they discovered remarkably high ammonia concentrations, roughly 100 times higher than the normal amounts seen in soils on Earth.
Ammonia is a necessary component of many biological processes, including the formation of amino acids, which can then join to form proteins in lengthy chains.
Researchers discovered signs of eleven minerals that were probably a part of a briny combination that was left behind after water deposits evaporated off Bennu and its parent asteroid, according to a second report published Wednesday in the journal Nature.
Tim McCoy, a co-author of both studies and curator of meteorites at the Smithsonian Natural History Museum in Washington, D.C., said the salty crystals left behind by the evaporated water mirrored sodium-rich crusts found in dry lakebeds on Earth, including Searles Lake in California.
According to a statement by McCoys, “we now know from Bennu that the raw ingredients of life were combining in really interesting and complex ways on Bennu’s parent body.” On the route to life, we have found the next step.
Sodium carbonate compounds like trona, often known as soda ash, were among the minerals found; the scientists claimed that these compounds had never been found in any previous alien material. It is believed that the dwarf planet Ceres and Saturn’s moon Enceladus have similar briny mixes.
The two recent investigations are the first comprehensive examinations of the Bennu samples. Researchers reported first results in 2023, including signs of water and carbon trapped in clay grains.
Although they are the first samples NASA has ever taken and returned from an asteroid, the rock and soil from Bennu are not the first in history. In 2010, Japan’s Hayabusa mission brought a few micrograms of material from the Itokawa asteroid to Earth. In 2020, a tiny sample was sent from the Ryugu asteroid by a second mission called Hayabusa2.
Even though the Bennu samples have already produced interesting findings, more investigation is required to determine the exact factors that lead to the emergence of life on some planets or moons but not others.
What did Earth have that Bennu did not? OSIRIS-REx project scientist Jason Dworkin of NASA’s Goddard Space Flight Center said. Considering Bennu as an example of a site that had everything but didn’t support life, this is a topic that astrobiologists worldwide will likely investigate in the future. What made Earth unique?