An international team of scientists has developed a model that predicts the presence of a carbon cycle on exoplanets. To do this, the algorithm needs mass, core size, and amount of CO2.
The researchers noted that in their search for life on planets outside our solar system, astronomers have no way to take pictures to see what is happening there. Modern telescopes do not have the necessary spatial resolution for this; exoplanets are too small and far away. However, the planet’s atmosphere can tell a huge amount of information about an object. Thus, scientists can determine what materials are present in the atmospheres of exoplanets.
In the quest for life, carbon is of great interest to researchers because of the cushioning effect of the carbon cycle on warming and cooling. Thanks to this cycle, the Earth has always maintained a temperature suitable for life, while the Sun has become 20% brighter over the past billions of years.
Scientists have developed a model that links the exoplanet’s mass and core size to the amount of CO2 in its atmosphere. Astronomers can now quantify these three factors for an exoplanet with a telescope, and a model can tell if a carbon cycle might exist there. The mass and size of the planet’s core are additional factors as they strongly influence plate tectonics, which plays a key role in the carbon cycle.
The carbon cycle has a moderating effect on temperature changes as the planet absorbs more CO2 as it gets warmer, which reduces the greenhouse effect. When it gets colder, the opposite effect occurs. The first step in the cycle is weathering: rocks react with CO2 and rainwater to form bicarbonate (HCO3). It settles to the seabed as sedimentary rock (CaCO3) and a small portion of the carbon is dissolved in the seawater as a residual product. Then plate tectonics transports sedimentary rocks into the Earth’s mantle. The volcanoes then release CO2 from the sediment back into the atmosphere.
“We don’t know if there are other planets with plate tectonics and carbon cycles,” said Mark Oosterloo, lead author of the article. – In our solar system, Earth is the only planet where we have discovered a carbon cycle. We hope that the new model can contribute to the discovery of an exoplanet with a carbon cycle, and therefore, possibly, life. “