Astrochemistry, Prebiotic Molecules, Origin of Life:

Discussion in 'Astronomy, Exobiology, & Cosmology' started by paddoboy, Jun 8, 2020.

  1. paddoboy Valued Senior Member

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    25,671
    https://phys.org/news/2020-06-complex-astrochemistry-thin-ice-grains.html

    New experiments show complex astrochemistry on thin ice covering dust grains:

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    Schematic figure showing dust grains (in grey) mixed with ice molecules (in blue), as well as the main external influences that facilitate chemical processing in deep space: heat, bombardment by atoms, ultraviolet radiation, and cosmic particle streams (cosmic rays). Credit: A. M. Quetz / MPI

    Astronomers from the Max Planck Institute for Astronomy and the University of Jena have obtained a clearer view of nature's tiny deep-space laboratories: tiny dust grains covered with ice. Instead of regular shapes covered thickly in ice, such grains appear to be fluffy networks of dust, with thin ice layers. In particular, that means the dust grains have considerably larger surfaces, which is where most of the chemical reactions take place. Hence, the new structure has fundamental consequences for astronomers' view of organic chemistry in space—and thus for the genesis of prebiotic molecules that could have played an important role for the origin of life on Earth.

    Creating complex molecules in deep space is anything but easy. To the best of current knowledge, the natural laboratories in which the necessary reactions take place are interstellar dust grains with icy surfaces. Now, new experimental results by Alexey Potapov of the MPIA laboratory astrophysics group at Jena University and his colleagues demonstrate that, under realistic conditions, the ice layers may well be so thin that the surface structure of the dust grains themselves plays an important role.

    This opens up a new field of study: Those who are interested in the cosmic origins of the organic precursor molecules of life will need to take a closer look at the different properties of the surfaces of cosmic dust grains, their interactions with small amounts of ice, and at the role the resulting complex environments play in helping to synthesize complex organic molecules.

    When we think about how life, and how we ourselves, have come to be in this universe, there are several important steps, encompassing physics, chemistry, and biology. As far as we know, the earliest biology of our own origins story took place here on Earth, but the same is not true for either physics or chemistry: Most chemical elements, including carbon and nitrogen, have been created by nuclear fusion inside stars ("We are star stuff," as Carl Sagan famously said).
    more at link............

    the paper:

    Ice Coverage of Dust Grains in Cold Astrophysical Environments:

    ABSTRACT:
    Surface processes on cosmic solids in cold astrophysical environments lead to gas-phase depletion and molecular complexity. Most astrophysical models assume that the molecular ice forms a thick multilayer substrate, not interacting with the dust surface. In contrast, we present experimental results demonstrating the importance of the surface for porous grains. We show that cosmic dust grains may be covered by a few monolayers of ice only. This implies that the role of dust surface structure, composition, and reactivity in models describing surface processes in cold interstellar, protostellar, and protoplanetary environments has to be reevaluated.


     
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  3. paddoboy Valued Senior Member

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    His another interesting aspect of science and the scientific method................

    https://phys.org/news/2020-06-ancient-asteroid-impacts-ingredients-life.html

    Ancient asteroid impacts created the ingredients of life on Earth and Mars:

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    Single stage propellant gun used for the simulation of impact-induced reactions at NIMS. Credit: Yoshihiro Furukawa

    A new study published in Scientific Reports reveals that asteroid impact sites in the ocean may possess a crucial link in explaining the formation of the essential molecules for life. The researchers discovered the emergence of amino acids that serve as the building blocks for proteins—demonstrating the role of meteorites in bringing life's molecules to Earth, and potentially Mars.

    There are two explanations for the origins of life's building molecules: extraterrestrial delivery, such as via meteorites, and endogenous formation. The presence of amino acids and other biomolecules in meteorites points to the former.

    Researchers from Tohoku University, National Institute for Materials Science (NIMS), Center for High Pressure Science & Technology Advanced Research (HPSTAR), and Osaka University simulated the reactions involved when a meteorite crashes into the ocean. To do this, they investigated the reactions between carbon dioxide, nitrogen, water, and iron in a laboratory impact facility using a single stage propellant gun. Their simulation revealed the formation of amino acids such as glycine and alanine. These amino acids are direct constituents of proteins, which catalyze many biological reactions.

    The team used carbon dioxide and nitrogen as the carbon and nitrogen sources because these gasses are regarded as the two major components in the atmosphere on the Hadean Earth, which existed more than 4 billion years ago.
    more at link.................

    the paper:
    Impact-induced amino acid formation on Hadean Earth and Noachian Mars:

    Abstract

    Abiotic synthesis of biomolecules is an essential step for the chemical origin of life. Many attempts have succeeded in synthesizing biomolecules, including amino acids and nucleobases (e.g., via spark discharge, impact shock, and hydrothermal heating), from reduced compounds that may have been limited in their availabilities on Hadean Earth and Noachian Mars. On the other hand, formation of amino-acids and nucleobases from CO2 and N2 (i.e., the most abundant C and N sources on Earth during the Hadean) has been limited via spark discharge. Here, we demonstrate the synthesis of amino acids by laboratory impact-induced reactions among simple inorganic mixtures: Fe, Ni, Mg2SiO4, H2O, CO2, and N2, by coupling the reduction of CO2, N2, and H2O with the oxidation of metallic Fe and Ni. These chemical processes simulated the possible reactions at impacts of Fe-bearing meteorites/asteroids on oceans with a CO2 and N2 atmosphere. The results indicate that hypervelocity impact was a source of amino acids on the Earth during the Hadean and potentially on Mars during the Noachian. Amino acids formed during such events could more readily polymerize in the next step of the chemical evolution, as impact events locally form amino acids at the impact sites.

    extract:
    "Extraterrestrial delivery is another source of the building blocks of life on prebiotic Earth54,55,56. Many amino acids have been detected from meteorites57,58. However, the amounts of the delivery remained unclear, because the composition of the building blocks of life in different carriers, particularly micrometeorites that are regarded as the largest carrier, remained unclear52,59,60. Further investigations regarding both endogenous formation and exogenous delivery are indispensable for understanding the availability of the building blocks of life on prebiotic Earth".

     
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  5. Xelasnave.1947 Valued Senior Member

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    I linked to this in my thread re theisist rejecting evolution to show V I hope you approve.
    Alex
     
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  7. paddoboy Valued Senior Member

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    No probs Alex! Not sure how impressed he or his two cohorts will be, but at least its better discussing science rather then some myth.
     

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