Mariana Reis


Luleå University of Technology

Evolution of comets and icy moons – ices, carbon, and mechanochemistry

Comets are thought to contain rubble left over from the formation of the solar system. They are therefore thought to contain the most primitive material, in the form of ice, dust, silicates, and some organics. They are also believed to be the key to understanding the origin of life. Although our knowledge of comets has increased in the wake of space missions like Rosetta, the origin of life in the solar system is still a mystery. To date, we still do not understand how the first, most basic building blocks of life have formed. It is difficult to explain where the significant energy needed for photochemical processes comes from in a cold, dark environment, such as stellar ice clouds. Therefore, the synthesis of simple organic compounds during the evolution of our solar system remains enigmatic. There are two aspects of energy transfer into icy bodies I investigate as part of this project. On the one hand, there is still a mismatch between mathematical models of comet nucleus surface evolution and experimental results from the lab. On the other hand, we do not know how particle microstructure and mechanical agitation affect the chemistry (solidstate photochemistry) of mixtures of ices, carbon, and iron minerals. I experimentally investigate the thermal and mechanical behaviour of cometary nucleus surfaces in the Planetary Ices Laboratory of Luleå University of Technology. First results indicate that energy transfer is highly dependent on the carbon content of the icy material.