2023-12-29 15:03:09
An international study has found that low levels of CO2 in a planet’s atmosphere can be a sign of its habitability. This will make it easier to identify these celestial bodies in the future.
The researchers, including those from the US elite university Massachusetts Institute of Technology (MIT) and the British University of Birmingham, were looking for a way to better analyze the 5,200 exoplanets known to date in the universe for possible habitability. Until now, only the distance to their sun and the duration of an orbit around the sun might be measured directly for these celestial bodies. From this it might be deduced whether the planet is in a habitable zone, but not whether it is actually habitable.
Ozone as a sign of extraterrestrial life
When comparing the Earth with the similar planets in our solar system (Mars and Venus), the experts found that, in addition to the similarities (made of rock and relatively close to the sun), the biggest differences are that only Earth has water can be found in liquid form – and the proportion of CO2 in the earth’s atmosphere is significantly lower. “We assume that the three planets formed in a similar way and that if we discover a planet with low carbon in the future, it must have evaporated somewhere,” explains study author Amaury Triaud from MIT. “The only process that can lead to such widespread removal of carbon from the atmosphere is a strong water cycle, which in turn suggests oceans with liquid water.” Even on Earth, a large part of the carbon dioxide is bound in the oceans.
The research team suggests paying particular attention to signs of low levels of CO2 in the atmosphere when searching for exoplanets in the future. If this is the case, the planet would be potentially habitable. The best way to check whether there is actually life on it is to determine the ozone content. Most life forms emit oxygen, which cannot be easily detected directly, but can be detected in the form of ozone as a reaction product with sunlight. “If we detect ozone, the chances are pretty high that it is linked to carbon dioxide, which is processed by living things,” says Triaud. “And if it’s regarding living beings, then probably higher life forms and not just bacteria.”
The Study”Atmospheric carbon depletion as a tracer of water oceans and biomass on temperate terrestrial exoplanets“is in the journal”Nature Astronomy” appeared.
Show all
Show all
1703870650
#method #discover #habitable #exoplanets
