Habitability of Exoplanets

Is there life on other planets? To answer this question, we first have to identify the most promising planets for life to evolve. For example, life needs liquid water, which requires a certain temperature range. The surface temperature of a planet depends on the distance to its star, but also on greenhouse gases in the atmosphere. Important is the long-term carbonate silicate cycle, consisting of volcanic degassing, weathering, and subduction of carbonates. Understanding this cycle for different types of exoplanets will help us to predict their habitability! read more

Feedback Loops and the Interior Evolution of the Earth

I am particularly fascinated by feedback loops in the Earth's evolution. Which parameters determine the behavior of the whole system? Which parameters are not really important? Feedback loops can couple the evolutions of the Earth's interior, crust, and atmosphere. Water and carbon dioxide are degassed at mid-ocean ridges, transported within the oceans and atmosphere, and subducted within sediments and minerals back into the mantle at subduction zones. Water in the Earth's mantle reduces the viscosity, thereby speeding up the convection rate. CO2 is greenhouse gas in the atmosphere with a strong effect on the surface temperature. How would the system work if, for example, the Earth would surround the sun at the orbit of Venus? How would the system behave without land plants that enhance the weathering rate and thereby the rates of sedimentation and volatile subduction? read more

Continental Growth and Implications for Exoplanets

Geochemical studies show that most of the Earth's continental volume was already present billions of years ago. However, this does not imply that continents are not produced anymore. Rather, there is a continuous equilibrium between continental production and erosion. How can we explain that this equilibrium did not change much over the past billion years despite the cooling of Earth's mantle? What does this mean for the continental cycle on exoplanets? read more