Possible organic compounds found in Mars crater rocks

Hexbyte Glen Cove

Jezero crater. Credit: NASA

A study published in Science analyses multiple rocks found at the bottom of Jezero Crater on Mars, where the Perseverance rover landed in 2020, revealing significant interaction between the rocks and liquid water. Those rocks also contain evidence consistent with the presence of organic compounds.

The existence of organic compounds ( with carbon–) is not direct evidence of life, as these compounds can be created through nonbiological processes. A future mission returning the samples to Earth would be needed to determine this.

The study, led by researchers at Caltech, was carried out by an international team including Imperial researchers.

Professor Mark Sephton, from the Department of Earth Science & Engineering at Imperial, is a member of the science team who took part in rover operations on Mars and considered the implications of the results. He said: “I hope that one day these samples could be returned to Earth so that we can look at the evidence of and possible organic matter, and explore whether conditions were right for life in the early history of Mars.”

Moving water

Perseverance previously found organic compounds at Jezero’s delta. Deltas are fan-shaped geologic formations created at the intersection of a river and a lake at the edge of the crater.

Mission scientists had been particularly interested in the Jezero delta because such formations can preserve microorganisms. Deltas are created when a river transporting fine-grained sediments enters a deeper, slower-moving body of water. As the spreads out, it abruptly slows down, depositing the sediments it is carrying and trapping and preserving any microorganisms that may exist in the water.

However, the crater floor, where the rover landed for safety reasons before traveling to the delta, was more of a mystery. In lake beds, the researchers expected to find , because the water deposits layer after layer of sediment. However, when the rover touched down there, some researchers were surprised to find igneous rocks (cooled magma) on the with minerals in them that recorded not just igneous processes but significant contact with water.

These minerals, such as carbonates and salts, require water to circulate in the igneous rocks, carving out niches and depositing dissolved minerals in different areas like voids and cracks. In some places, the data show evidence for organics within these potentially habitable niches.

Discovered by SHERLOC

The minerals and co-located possible organic compounds were discovered using SHERLOC, or the Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals instrument.

Mounted on the rover’s , SHERLOC is equipped with a number of tools, including a Raman spectrometer that uses a specific type of fluorescence to search for and also see how they are distributed in a material, providing insight into how they were preserved in that location.

Bethany Ehlmann, co-author of the paper, professor of planetary science, and associate director of the Keck Institute for Space Studies, said: “The microscopic compositional imaging capabilities of SHERLOC have really blown open our ability to decipher the time-ordering of Mars’s past environments.”

As the rover rolled toward the delta, it took several samples of the water-altered igneous rocks and cached them for a possible future sample-return mission. The samples would need to be returned to Earth and examined in laboratories with advanced instrumentation in order to determine definitively the presence and type of organics and whether they have anything to do with life.

More information:
Eva L. Scheller et al, Aqueous alteration processes in Jezero crater, Mars−implications for organic geochemistry, Science (2022). DOI: 10.1126/science.abo5204

Citation:
Possible organic compounds found in Mars crater rocks (2022, November 24)
retrieved 25 November 2022
from https://phys.org/news/2022-11-compounds-mars-crater.html

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Hexbyte Glen Cove Scientists use radiography to understand the evolution of liquid and solid microjets thumbnail

Hexbyte Glen Cove Scientists use radiography to understand the evolution of liquid and solid microjets

Hexbyte Glen Cove

This representative dynamic image shows the base sample, emerging jet, no-groove control region and static calibration foils. Credit: Lawrence Livermore National Laboratory

Lawrence Livermore National Laboratory (LLNL) scientists have experimentally tested the predictions of a 2020 study that computationally investigated the effect of melting on shock driven metal microjets. That earlier work predicted that melting the base material does not necessarily lead to a substantial increase in jet mass.

The LLNL team confirmed the predictions of microjet behavior with liquid and solid tin microjet experiments. The work, led by LLNL scientist David Bober, is featured in the Journal of Applied Physics and was chosen as an editor’s pick.

Bober said microjets are important to study because they are examples of broader jetting and ejecta processes that occur throughout shock physics, meaning anything from explosives to asteroid impact.

Bober said the team was motivated by a set of simulations performed by LLNL design physicist Kyle Mackay, who is also a co-author of the present study. The work lead by Mackay can be found here and summarized here.

“Mackay’s simulations showed a very surprising trend and we basically wanted to see if it was real,” Bober said. “Specifically, that work predicted that melting the base material might not always lead to a dramatic increase in the mass of material ejected from a surface feature, which goes against the of how these things are supposed to work.”

The research was conducted by cutting a small groove in the top of a tin plate. The team then hit the bottom side with a fast-moving projectile. That caused a fluid-like jet of tin to be thrown forward from the groove and into the path of an intense X-ray beam.

“We used those X-rays and an array of high-speed cameras to take a series of pictures of the flying tin jet, which then let us calculate things like the jet’s mass and velocity,” Bober said. “For the ability to do all that, we are indebted to many colleagues, especially those at the Dynamic Compression Sector at the Advanced Photon Source at Argonne National Laboratory.”

Bober said he is excited to explain how the results occur in nature and in simulations. The team has recently collected follow-up data measuring the local phase of the jets and also plan future shots to explore the material parameters they think might be most important to the phenomena.

“The team still does have work ahead of them to understand what exactly is going on in the experiments,” Bober said. “I hope we are on the path to improving ejecta models by detailing the physics that happens around the melt transition.”



More information:
David B. Bober et al, Understanding the evolution of liquid and solid microjets from grooved Sn and Cu samples using radiography, Journal of Applied Physics (2021). DOI: 10.1063/5.0056245

Citation:
Scientists use radiography to understand the evolution of liquid and solid microjets (2021, July 29)
retrieved 29 July 2021
from https://phys.org/news/2021-07-scientists-radiography-evolution-liquid-solid.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or resea

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