The asteroid Bennu is full of surprises that keep on coming, each one helping scientists close in on answers to the origins of life. The latest inspections of Bennu’s samples reveal that the asteroid almost sounds like it could’ve been home to an old candy shop, carrying sticky space gum, sugars, and an absurd amount of dust.
A trio of studies has shed light on the complexity of Bennu’s surface, giving insight on where Bennu came from and how it procured the earliest ingredients of life. By studying the clues hidden within Bennu, scientists may start to grasp what was happening in the earliest days of the Solar System, and even what allowed life to arise on Earth in the first place.
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Starting Life with Sugars
In one study published in Nature Geoscience, researchers found compounds in samples from Bennu that may hint at the molecular workings of the first life forms. Two sugars were discovered: the five-carbon sugar ribose and the six-carbon sugar glucose, the latter of which has never before been seen in an extraterrestrial sample.
While these sugars don’t indicate evidence of life, they now join several other building blocks of life — like amino acids, nucleobases, and carboxylic acids — that have previously been uncovered in Bennu samples. With the sugars and other building blocks, researchers are now closer to understanding how RNA may have played a role in the origins of life
While ribose helps form the backbone of RNA, the backbone of DNA relies instead on the sugar deoxyribose, which grants DNA enhanced stability compared to RNA.
Notably, however, researchers didn’t find deoxyribose in the Bennu samples. This may indicate that ribose was more abundant than deoxyribose in the early solar system; it also supports the theory that the first forms of life used RNA as a primary molecule to store information and sustain themselves through chemical reactions.
The Oddity of Bennu’s Space Gum
Bennu’s surface also had another sweet surprise in store for researchers; a study published in Nature Astronomy revealed the presence of an ancient gum-like substance on Bennu samples, a material that has never been observed before.
The mysterious gum, composed of polymer-like materials rich in nitrogen and oxygen, appears to have evolved over time to become water-resistant. It has survived all the changes that the asteroid went through, even when Bennu’s parent body was warmed enough to become host to a watery environment.
“With this strange substance we’re looking at, quite possibly, one of the earliest alterations of materials that occurred in this rock,” said Sandford. “On this primitive asteroid that formed in the early days of the Solar System, we’re looking at events near the beginning of the beginning,” said study author Scott Sanford, an astrophysicist at NASA’s Ames Research Center, in a statement.
To get a better look at the material and its odd consistency, the researchers took tiny carbon-rich grains in Bennu samples and shaved them down with a beam of charged particles to be a thousand times thinner than a human hair.
The translucent material, like used gum or soft plastic, was pliable, but it was also oddly brittle because of exposure to radiation in space. The researchers say that it shows parallels with polyurethane, a plastic material, but has a more complicated mixture of elements.
Packed with Supernova Dust
The last study, also published in Nature Astronomy, looked at grains that predate the Solar System, existing in two different types of rocks from the Bennu samples. These presolar stardust grains are generally found at trace levels in meteorites and come from supernovae and novae.
Researchers found that the Bennu samples contained six times the amount of supernova dust as any previously studied space material. This may indicate that Bennu’s parent body formed in a region filled with the dust of dying stars.
The study also showed that while Bennu has endured many changes from fluids, its samples still contain pockets of materials that aren’t as drastically altered, which will continue to be a crucial target for researchers.
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Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
- This article references information from the recent study published in Nature Geoscience: Bio-essential sugars in samples from asteroid Bennu
- This article references information from the recent study published in Nature Astronomy: Nitrogen- and oxygen-rich organic material indicative of polymerization in pre-aqueous cryochemistry on Bennu’s parent body
- This article references information from the recent study published in Nature Astronomy: Abundant supernova dust and heterogeneous aqueous alteration revealed by stardust in two lithologies of asteroid Bennu
Qiana Howe
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