Did you catch the announcement of the TRAPPIST-1 systems recently? If you haven’t then this is a star system that has total of seven planets, each of which is sized similar to our own Earth and thus naturally raises the question – how many of these planets are capable of bearing life?
Just the discovery of such a star system has left the scientific community in a lurch. As is the case with something unheard or unseen, it brings more questions than it manages to answer. Something that this discovery has managed to shatter though is the belief that any star system can probably have zero to three habitable planets at best. Here’s a star system now that has potentially 7 planets all capable of having life.
Let’s get started with what we know thus far and hence try and answer the question of life. First, because of the tight orbits, these planets probably are tidally locked. This is a unique phenomenon, which is closer to our planet than you think. See the moon? Have you ever wondered why you keep seeing the same face of the moon at all times? That is because it is tidally locked to earth or in other words, it always shows one face to earth and that is why we have a dark and light side of the moon. Basically, all seven planets of the TRAPPIST-1 system show the same side to their star.
What this means is that the cores of the planets will be hot due to the gravitational tug of the star and the tidal locking. Also, the planets will have volcanism, which holds truer for the closest two planets. Nevertheless, the promise of extra-terrestrial life does continue. This is because, the middle three planets all fall under the habitable zone and because the star in question here isn’t like our own star, because it is smaller and most of its energy is in infrared, the planets beyond the habitable zone too could potentially harbour water in all its three states while having a pleasant climate. The real question therefore remains as to which planets have an atmosphere capable of circulating the heat from the light to the dark side efficiently enough to provide a living environment for life.