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Polymers in meteorites provide clues to early solar system

Date:
June 29, 2021
Source:
American Institute of Physics
Summary:
Meteorites that do not experience high temperatures at any point in their existence provide a good record of complex chemistry present when or before our solar system was formed. So researchers have examined individual amino acids in these meteorites, many of which are not in present-day organisms. Researchers now show the existence of a systematic group of amino acid polymers across several members of the oldest meteorite class, the CV3 type.
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Many meteorites, which are small pieces from asteroids, do not experience high temperatures at any point in their existence. Because of this, these meteorites provide a good record of complex chemistry present when or before our solar system was formed 4.57 billion years ago.

For this reason, researchers have examined individual amino acids in meteorites, which come in a rich variety and many of which are not in present-day organisms.

In Physics of Fluids, by AIP Publishing, researchers from Harvard University show the existence of a systematic group of amino acid polymers across several members of the oldest meteorite class, the CV3 type. The polymers form organized structures, including crystalline nanotubes and a space-filling lattice of regular diamond symmetry with density estimated to be 30 times less than water.

"Because the elements required to form our polymers were present as early as 12.5 billion years ago, and there appears to be a gas phase route to their formation, it is possible that this chemistry was and is present throughout the universe," said author Julie McGeoch.

Preventing terrestrial contamination was a top priority for the researchers. They devised a clean room method using a clean stepper motor with vacuum-brazed diamond bits to drive several millimeters into the meteorite sample before retrieving newly etched material from only the bottom of the hole. Several drill bits were used in a single etch, all being cleaned with ultrasonification.

The resulting micron scale meteorite particles were then placed in tubes and stored at minus 16 degrees Celsius. Polymers were induced to diffuse out of the micron particles via Folch extraction, which involves two chemical phases related to different solvents with different densities.

Mass spectrometry revealed the existence of the polymers, which were composed of chains of glycine, the simplest amino acid, with additional oxygen and iron. They had a very high deuterium-to-hydrogen-isotope ratio that confirmed their extraterrestrial origin.

This research was inspired by observations on a small, highly conserved biological protein that entrapped water. That finding suggested if such a molecule could form in gas phase space, it would aid early chemistry by supplying bulk water.

The researchers employed quantum chemistry to show amino acids should be able to polymerize in space within molecular clouds, retaining water of polymerization. Many experiments followed using meteorites as the source of polymer culminating in 3D structures.

Going forward, the researchers hope to get more detail of the glycine rods via continued X-ray analysis. Other polymers in the same class remain to be characterized and could reveal the energetics of polymer formation.


Story Source:

Materials provided by American Institute of Physics. Note: Content may be edited for style and length.


Journal Reference:

  1. Julie E. M. McGeoch, Malcolm W. McGeoch. Structural organization of space polymers. Physics of Fluids, 2021; 33 (6): 067118 DOI: 10.1063/5.0054860

Cite This Page:

American Institute of Physics. "Polymers in meteorites provide clues to early solar system." ScienceDaily. ScienceDaily, 29 June 2021. <www.sciencedaily.com/releases/2021/06/210629120835.htm>.
American Institute of Physics. (2021, June 29). Polymers in meteorites provide clues to early solar system. ScienceDaily. Retrieved July 24, 2024 from www.sciencedaily.com/releases/2021/06/210629120835.htm
American Institute of Physics. "Polymers in meteorites provide clues to early solar system." ScienceDaily. www.sciencedaily.com/releases/2021/06/210629120835.htm (accessed July 24, 2024).

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