C.6: Production of secondary atmospheres
Atmospheres not only play a vital role in determining the habitability of planets, but they are also expressions of the nature and constitution of their interiors. The rocky planets of our Solar System possess atmospheres that were produced by evaporation of the very material from which they are composed. However, our knowledge of how atmospheric compositional diversity arose is limited by a lack of experimental data on the dissolution of gases in magma.
Our objective in the project Production of secondary atmospheres, is to calibrate the solubilities of majour atmosphere-forming elements (H, C, O, N, Cl and S) in magmas and hence determine the nature of atmospheres produced around rocky planets by volcanic activity. These elements are important as they are required as key building blocks for life on Earth. Although reduced atmospheres, consisting of methane (CH4) and ammonia (NH3), were found to be suitable for the generation of amino acids and other prebiotic compounds in the famous Miller-Urey experiment, whether such atmospheres ever existed on Earth is a central question explored in this project.
The experimentally based approach employed here uses laser heating to generate temperatures in excess of 2000°C, representing a miniature planet, ‘levitating’ on a stream of gas to simulate changing atmospheric conditions in the laboratory. The composition and speciation of the magma and surrounding gas is revealed by infrared spectroscopy. With these new measurements, we will be able not only to take a look back through time in Earth’s history, but also look beyond the confines of our Solar System to interpret measurements made by next-generation telescopes on the composition of planets orbiting other stars.
An artistic illustration of Earth today and 4.5 billion years ago. Credit: Tobias Stierli/NCCR PlanetS
