A new study has developed a framework to analyse the atmospheres of distant planets and locate those suitable for human habitation.
Due to the threat of the current climate crisis, scientists have begun to search for distant planets, outside our Solar System, where humans could potentially settle.
Dr Assaf Hochman, from the Fredy & Nadine Herrmann Institute of Earth Sciences at the Hebrew University of Jerusalem (HU), in collaboration with Dr Paolo De Luca at the Barcelona Supercomputing Center, and Dr Thaddeus D Komacek at the University of Maryland, have successfully analysed the potential living conditions of exoplanets without having to visit them.
The joint research, titled ‘Greater Climate Sensitivity and Variability on TRAPPIST-1e than Earth’, was published in The Astrophysical Journal.
Measuring the climate conditions and sensitivity of exoplanets
The processes that drive the climate variability of exoplanets are unknown, but for rocky planets, they are likely to include weather and extreme climate events similar to Earth, such as heat waves, hurricanes, drought, and cold spells.
When assessing the viability of distant planets for human habitation, scientists must classify their climate conditions and measure their sensitivity.
The researchers examined TRAPPIST-1e, an exoplanet located around 40 light years from Earth and scheduled to be documented by the James Webb Space Telescope in the coming year. They examined the sensitivity of its climate to increases in greenhouse gases, and compared it with conditions on Earth.
By using a computerised simulation of the climate on TRAPPIST-1e, the team were able to assess the impact of changes in greenhouse gas concentration. To do this, they initialised the atmosphere from the end state of previous TRAPPIST-1e simulations.
After analysing the simulations, the scientists believe that this distant planet has an oceanic surface with a depth of 50 metres, zero ocean heat transport, zero orbital eccentricity, and zero planetary obliquity.
How does TRAPPIST-1e compare to Earth?
The study focused on the effect of an increase in carbon dioxide during extreme weather conditions, and on the rate of changes in weather on the distant planet.
“These two variables are crucial for the existence of life on other planets, and they are now being studied in depth for the first time in history,” explained Hochman.
According to the research team, studying the climate variability of Earth-like exoplanets provides a better understanding of the climate changes we are currently experiencing on Earth. Additionally, this kind of research offers a new understanding of how planet Earth’s atmosphere might change in the future.
The team found that exoplanet TRAPPIST-1e has a significantly more sensitive atmosphere than Earth. They estimated that an increase in greenhouse gases there may lead to more extreme climate changes than those we would experience on Earth. This is because one side of TRAPPIST-1e constantly faces its own sun, in the same way our own Moon always has one side facing Earth.
Hochman concluded: “The research framework we developed, along with observational data from the James Webb Space Telescope, will enable scientists to efficiently assess the atmospheres of many other planets without having to send a space crew to visit them physically. This will help us make informed decisions in the future about which planets are good candidates for human settlement, and perhaps even to find life on those planets.”