Just last week, NASA announced about the TRAPPIST-1 system which has seven exoplanets where three are deemed to be habitable due to the presence of liquid water. With the recent finding of the Cornell University, it seems that a fourth planet can also be livable.
In an article in Gizmodo, the Cornell University released new models of the TRAPPIST-1 system. In these models, the Cornell University explained that the fourth planet in the TRAPPIST-1 system also has the ability to house liquid water just like the other three exoplanets. The scientists from the university also explained that the fourth planet is rich in hydrogen which strengthens its possibility to be habitable.
Ramses Ramirez, one of the scientists studying the TRAPPIST-1, imparted in the same article that they were also able to notice that the outermost planet in the system is capable of having oceans in it. Ramirez also added that their indicators of life are generally two known compounds, the carbon dioxide, and the water. But, with additional greenhouse gasses, he also stated that it can extend the possibility of life to the innermost planets just like with the fourth planet which has hydrogen.
Several scientists believed that planets which have atmospheres rich in hydrogen can create and maintain liquid water just like the Earth. However, the seven exoplanets of the TRAPPIST-1 system has a rocky composition different to Earth and the case might also be different. With this, Ramirez' team created models for the TRAPPIST-1 exoplanets and ran some climate tests. The results showed that with the presence of hydrogen in the atmosphere of the exoplanets, it can also increase and expand the number of habitable planets up to 60 percent.
Research on the TRAPPIST-1 system continues. According to Space, NASA had several notable observations of the seven exoplanets which started even last year. In 2016, two of the exoplanets are found out to be rocky rather than gaseous and in May last year, NASA also announced that three of the seven exoplanets are habitable.
With this new space endeavor, scientists are revisiting the question, "are we alone". Ramirez and his colleagues are trying their best to answer that and hope to see more developments soon.
