Glycine meteorite polymers shed light on pre-solar space chemistry

Glycine meteorite polymers shed light on pre-solar space chemistry. Asteroid material in Vigarano-class change 3 (CV3) chondritic meteorites provides a good record of the complex chemistry of our solar system 4.57 billion years ago or earlier, according to a team of researchers from Harvard University and PLEX. Corporation.

Shed Light

The PAH molecule overlaps the Taurus Molecular Cloud, a large cloud of bluish-white gas and dust that contains large and small stars of varying brightness. Image credit: Smithsonian Center for Astrophysics.

“Molecular clouds are regions within the high vacuum of space with low levels of hydrogen, helium, and small molecules containing hydrogen, lithium, carbon, nitrogen and oxygen, extending to ethylene glycol and polyaromatic hydrocarbons,” he said. Dr. Julie McGeoch of Harvard University and Dr. Malcolm McGeoch of PLEX Corporation.

It has been predicted that glycine, the simplest amino acid, should be able to form, but this has not been observed, possibly due to its polymerization, which is exothermic under conditions of hot, dense molecular clouds. In meteorite material obtained from asteroids, we observed various glycine polymers.

In the new study, the researchers examined different amino acid polymers in various CV3-type meteorites (such as Acfer 086 and Allende). Polymers form organized structures, consisting of crystalline nanotubes and a regular symmetry space-filling network of diamond, whose density is 30 times less than that of water.

“Since the elements needed to make our polymers were present around 12.5 billion years ago, and there appears to be a gas-phase pathway for their formation, it is possible that this chemical was and is present throughout the universe,” said Dr. Julie McGeoch. .

3 layers of hydrogen bonded

three layers of hydrogen bonded edge-to-edge polymers; Each layer consists of four polymer rods attached to a central vertex; Atoms are colored as follows: hydrogen white, carbon black, nitrogen blue, oxygen red, silicon pink, and iron green. Preventing land-based pollution was one of the scientists’ top priorities.

They devised a clean room method by using a clean stepping motor with vacuum brazed diamond bits to drive several millimeters into the meteorite sample before retrieving the freshly etched material from the bottom of the hole. Several bits were used in the same engraving, all being cleaned by ultrasound.

The resulting micrometer-scale meteorite particles were placed in tubes and stored at minus 16 ° C. The polymers were induced to disperse out of the micrometer particles by Folch extraction, which involves two chemical phases belonging to different solvents with different densities.

Mass spectrometry revealed the existence of the polymer, which was composed of glycine chains with additional oxygen and iron. They had a very high ratio of deuterium to hydrogen isotopes that confirmed their extraterrestrial origin.

“In the future, we hope to learn more about glycine rods through continuous X-ray analysis,” the authors said. Other polymers in the same class remain the feature and can reveal the polymer’s formation energy. The team’s results were published in the journal Physics of Fluids.

A 4.56 billion-year-old igneous meteorite contains clues to the planet’s building blocks. Northwest Africa (NWA) 11119, a stony meteorite found in Mauritania in December 2016, is the world’s oldest igneous meteorite, according to new research. An artist’s rendering of NWA 11119 (lower right corner of illustration), the oldest igneous meteorite. Image credit: University of New Mexico.

Planet’s building blocks

“The age of NWA 11119 is the oldest igneous meteorite ever recorded,” said Professor Carl Agee of the University of New Mexico, a co-author of the study. Not only is it an extremely unusual rock, but it tells us that not all asteroids look alike. Some of them almost resemble the earth’s crust because they are very light in color and full of SiO2. Not only do they not exist, but it happened during one of the first volcanic events to occur in the Solar System.

Using an electron microprobe and computed tomography, Professor Edge and his colleagues investigated the composition and mineralogy of NWA 11119. The mineralogy of this rock is very different from anything we’ve worked on before, said study lead author Poorna. Srinivasan. , also from the University of New Mexico.

We investigate mineralogy to understand all the phases of the meteorite. One of the main things we first noticed was the large silica crystals of tridymite, which is similar to the mineral quartz. When we did further image analysis to quantify tridymite, we found that the amount present was a staggering 30% of the total meteorite, an unheard of amount in meteorites and only found in some volcanic rocks on Earth at these levels.

NWA 11119 is a single 453g stone and resides in the Maine Museum of Gems and Minerals. A 23 g subsample deposited at the University of New Mexico Institute of Meteorology was used for this study. “Based on oxygen isotopes, we know that NWA 11119 comes from an extraterrestrial source somewhere in the Solar System, but we can’t really point to a known body that has been observed with a telescope.”

However, through measured isotopic values, we were able to possibly link it to two other unusual meteorites (NWA 7235 and Almahata Sitta), suggesting that they are all from the same parent body, perhaps a larger geological form formed from the primitive solar system. One possibility is that this parent body was shattered by a collision with another asteroid or planet and some of its ejected fragments eventually reached Earth’s orbit, fell through the atmosphere, and ended up on the ground as meteorites.

“The oxygen isotopes of NWA11119, NWA 7235 and Almahata Sitta are all similar, but this rock is completely different from any of the more than 40,000 meteorites found on Earth,” Srinivasan said. Most meteorites are formed by the collision of asteroids orbiting the Sun in a region called the asteroid belt. Asteroids are remnants of the formation of the Solar System about 4.6 billion years ago.

The chemical composition ranges of ancient igneous meteorites, or achondrites, are important for understanding the diversity and geochemical evolution of planetary building blocks. Achondrite meteorites record the first episodes of volcanism and crusting, most of which are basaltic.

“The meteorite we studied does not look like any other known meteorite. It has the highest abundance of silica and the oldest age (4.565 million years) of any known igneous meteorite,” said a study co-study graduate student at Arizona State University. author Daniel Dunlop.

These meteorites were precursors to the formation of planets and represent an important step in the evolution of rocky bodies in our Solar System. This research is published in the journal Nature Communications.

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