We may not be the only ones in the Universe, after all.
Ever since the Spitzer telescope identified seven Earth-like planets not more than forty light years away from us, scientists and researchers have been busy speculating the possibilities of life in the Transiting Planets and Planetesimals Small Telescope(TRAPPIST-1) system. Tucked away in the Aquarius constellation and hosted by an ultra-cool dwarf, it was discovered by the transition method.
A transition occurs when a planet(possibly) comes in between Earth and the host star, causing a dark shadow in that particular area. The luminosity of the transition before and after are recorded to determine the amount of light absorbed by the planet and its atmosphere. In a few cases, because the distance is large and transition time is low, the body can be mistaken for a planet when it is actually an asteroid. But transition method has helped identify more than a thousand exoplanets till date, most of them discovered by the Kepler telescope.
The seven planets identified so far orbit an ultra-cool dwarf and the whole system is so tiny and tightly packed that it fits in the distance between our Sun and Mercury. The theory has it that if you stand on one of these planets and look upwards, you can practically spot clouds on neighbouring planets.
Even though all the planets are Earth-like, there is a fundamental difference between our solar system and theirs. They do not rotate. At all. Known as tidal locking, one part of the planet faces the star at all times while the other is in complete darkness. In our solar system, the moon is tidally locked with our planet.
While tidal locking raises issues about the habitability of the planet, there are a lot more factors to be considered before any kind of conclusion can be drawn. A planet which is tidally locked will inevitably have a region where the daylight and night merge or begin. It is in this region that life might be possible. Also, determining the age of the host star is important since a young star spurts out energetic flares that can wipe out life if any. Even the planets’ orbits are unstable during early stages. Both of them cool with time and TRAPPIST-1 System is believed to have been quiet for a long time now.
Out of the seven planets, three of them are said to be in the habitable zone where liquid water might exist for life as we know it to sustain. Again, since the whole system is tight, the atmosphere and water might have been wiped out. But if there is a thicker atmosphere out there, as will be determined by James Webb Telescope in the future, it can help distribute heat across the surface.
There are a lot of secrets to be unlocked in the TRAPPIST-1 system. With a complete solar system where all its planets are Earth-like, it is a one of a kind discovery. The conditions just seem to be right for life to sustain.
Was there life in the past? Is there life there now? If so, how do they look like? Is there any way we can communicate?
We’ll just have to wait until more advanced telescopes make their way through space to provide us with the answers we seek.