Asteroid fragments brought to Earth may provide clues to the origin of life

Before Earth had biology, it had chemistry. How one followed from another – how boring a bunch Molecules transformed themselves into this special substance we call life – the greatest unknown to science. It’s a big reason why NASA sent the robotic spacecraft OSIRIS-REx on a multi-year mission around the Sun to retrieve some debris from the ancient asteroid Bennu and bring it back to Earth.

On Monday, the scientific community got its first glimpse of those precious, exotic objects, revealed by the mission’s top scientist, Dante Lauretta, at the fall meeting of the American Geophysical Union in San Francisco.

Lauretta, a planetary scientist at the University of Arizona, showed slides with a long list of intriguing molecules, including carbon-based organics, in grains and pebbles derived from Bennu. They will shed light on the solar system’s molecular building blocks and “perhaps — and still very early — insights into the origins of life.”

This analysis has just begun. The team has yet to publish a formal scientific paper. In his speech, Lauretta cited an interesting triangular, light-colored stone that contained something she had never seen before in a meteorite.

“Now scratching your head. What is this thing?” he said.

In an interview after the lecture, Lauretta said the sample was about 5 percent carbon. “It’s a very carbon-rich sample — the richest of all our extraterrestrial material. … We’re still unraveling the complex organic chemistry, but really understanding is promising: Do these carbon-rich asteroids provide basic molecules that could contribute to the origin of life?”

Laboratory analysis looks for other molecules and compounds important to life on Earth, such as amino acids, lipids, sugars and the bases of the genetic code, Lauretta said. The results so far are exciting. Team It is still refining its report, which will be discussed at a scientific meeting early next year, he said.

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NASA chose to send a portion to Bennu because it is the most dangerous asteroid in the solar system. Its orbit around the Sun is similar to that of the Earth. Every six years a rock about thirty-tenths of a mile in diameter (large enough to attract your attention, but not large enough to have a destructive impact) crosses our planet. orbital path.

A calculation Released in 2021, Bennu has an estimated 1 in 2,700 chance of hitting Earth in September 2182. That estimate will be refined after the asteroid approaches in 2135.

On the off chance that Earthlings want to knock on a rock, they want to know exactly what they’re hitting. A telescope does not provide as much information as a robotic viewer. Hence, OSIRIS-REx (which is the Origin, Spectral Interpretation, Resource Identification and Conservation – Regolith Explorer).

Even before the scientists began analyzing the samples, one thing was firmly established: Bennu was extremely black.

“It’s super black. It’s so black it’s hard to photograph,” project scientist Jason Dworkin said ahead of the meeting. The object includes “all kinds of shades of black” — And mysterious flashes of yellow and red and pink, he added.

A profession’s worth

NASA launched the OSIRIS-REx spacecraft in 2016 and it reached Bennu in 2018. In 2020 a robotic arm performed a series of delicate maneuvers to touch the asteroid with a sampling device. The arm unexpectedly plunged deep into the asteroid, which scientists call a rubble pile made up of loosely aggregated material held together by gravity.

The spacecraft then returned close to Earth and released the capsule containing the sample. On 24 September it was almost completely on target at a military bombing and training range in western Utah. The capsule showed no stress from its long journey and, in fact, sat upright on the desert floor at some comfortable speed off a road.

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The carefully sealed capsule was then transported to NASA’s Johnson Space Center in Houston. Next came the more delicate task of retrieving items from Bennu. Inside the capsule was a vial, which, in turn, contained a sampling device. The vial was opened, but the sampler did not cooperate. It is sealed with 35 specially designed fasteners, two of which are immovable.

NASA is designing a new instrument that should complete the job in the coming weeks. Meanwhile, a step NASA blog postThe sampling device is transferred to another container and “surrounded by a sealed Teflon bag to ensure that the sample is kept safely in a stable, nitrogen-rich, environment.”

However, no one panicked: a member of the team realized that using tweezers and scoops, it was possible to retrieve some of the material trapped inside the device. As a result, the team received a 70-gram sample, exceeding the official mission requirement of 60 grams.

“This is a career-value object for thousands of researchers around the world, so we’re ecstatic,” Lauretta said. “I fully expect the cosmochemistry community to go to town on this.”

“We’re getting a lot of information from a very small sample size,” NASA astrophysicist Danny Clavin said ahead of the meeting.

Bennu is part of a larger object that broke up during a collision early in the solar system’s history, scientists believe. The mother body, heated by radioactive decay, would have been hot enough for the internal water to be in liquid form.

“If you add water, you can do a lot of interesting chemistry,” Clavin said.

It would not be prejudice to say that chemistry becomes more interesting when it somehow produces an organism. Paleobiologists know that life as bacteria existed on Earth at least 3.5 billion years ago—relatively soon after the planet survived the violent bombardment from rocks that littered the solar system in its youth.

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Bennu’s mother body may not have contained anything alive, but it may have cooked up interesting compounds similar to those that formed the building blocks of life on Earth, which, as Dworkin said, “had to start with chemistry. In space.”

However, prebiotic chemistry is far from a single bacterium — “from Thanksgiving dinner to a bottle of vitamins,” Dworkin said.

This space dirt has astronomical import. By looking at the prebiotic chemistry on Bennu, scientists will have a better understanding of what they’re looking for when they find suspicious molecules in the Solar System, such as Mars, Jupiter’s moon Europa, or Saturn’s moon Enceladus.

“It’s an almost perfect laboratory control from non-biological chemistry,” Clavin said. “It prepares us to look for places that might have had life at one point — on Mars or Europa or Enceladus.”

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