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An Asteroid Sample Just Changed What We Know About Life in Our Solar System
...Eventually, those intelligent mammals would send a spacecraft called OSIRIS-REx to retrieve a sample of this rock in an attempt to better understand the early universe and the chances of life hiding elsewhere in the Solar System (and beyond). On September 24, 2023, a 4.3-ounce Bennu sampleāperfectly preserved within OSIRIS-RExās nitrogen-filled gloveboxācrash-landed in the Utah desert.
Now, twin studies published in the journals Nature and Nature Astronomy are writing the next chapter of Bennuās incredible 4.5 billion-year-old-storyāand this oneās a real doozy. After close examination of the unspoiled sample, NASA and other scientists from around the world have confirm it a treasure trove of lifeās building blocks. In a press statement, NASA is quick to clarify that they havenāt found life, but that this collection of amino acids, nucleobases, and minerals known as āevaporitesā suggests that the conditions for life to take hold were widespread across the early Solar System.
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This discovery wasnāt completely unexpected. Scientists discovered evidence of water on Bennu back in 2018, and soon after retrieval of the sample, NASA confirmed Bennu was rich in carbon. But now we know just how rich it really was. The Nature Astronomy paper reports that the sample contains 14 of the 20 amino acids (which make proteins) found on Earth, all five nucleobases life uses for storing and transmitting genetic instructions, and high levels of ammoniaāwhich can aid in the formation of amino acids.
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If that wasnāt enough, another teamāled by meteorite experts and cosmic mineralogists at Smithsonianās National Museum of Natural History and the Natural History Museum in Londonāfound 11 minerals that only form when water containing dissolved salts evaporates (aka āevaporitesā).
āWe also learned that these minerals, formed when water evaporates, disappear when exposed to water once againāeven with the tiny amount of water found in air,ā the authors co-wrote in a post on The Conversation. āThat explains why we canāt find these minerals in meteorites that have been on Earth for decades to centuries.ā
As with any major discovery, Bennu also inspires more questions. For example, life on Earth only produces what are referred to as left-handed amino acids, but the asteroid contains an equal amount of left and right amino acids. Itās still a mystery why life adopted this left-handedness, and one scientists eventually hope to solve as they gather more information.
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