https://phys.org/news/2020-06-complex-astrochemistry-thin-ice-grains.html New experiments show complex astrochemistry on thin ice covering dust grains: Please Register or Log in to view the hidden image! 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.