A few days ago NASA announced a major press conference which was to be attended my elite astronomers from around the world, and the only clue we had about the subject of this meeting was that it was something huge! So naturally space fanatics like me got excited and started guessing what the big news might be? Well, by the end of the day we were not disappointed, the news was about the discovery of a planetary system with not one, or two but seven potentially ‘Earths’.
The system called TRAPPIST-1 after the Transiting Planets and Planetesimals Small Telescope in Chile where the astronomer Michael Gillon first discovered them in May 2016, is about 35-40 light years away from us in the constellation Aquarius. The parent star is a Ultra-Cold Dwarf, a bit bigger than Jupiter, whose radiations are mainly in the infrared region unlike our Sun, which is comparably much much bigger and brighter which radiations in the visible region mostly. Michael, first found three planets around the star, but later NASA’s Spitzer telescope found the remaining four planets, and using Hubble Space Telescope which analysed their atmosphere and composition showed that they were rocky planets.
The planets were discovered using a method called ‘Transit Photometry’ which basically uses the chance in intensity of the star’s brightness when a planet passes in front of it and then using this data to calculate the size of the planet and then the relative orbits and motion of these planets helps us calculate the mass. Due to the very very small size of the parent star the planets lie very close to the star, so close indeed that the orbit of the seventh planet is almost as far as the orbit of Mercury from the Sun. So if you were to stand on one of these, you would be able to see the other planet’s cloud formations, with the planets sometimes appearing larger than the moon appears to us.
The star emits very dim light, about 200 times less than that of sun,like during sunset, but the warmth remains the same, because of the infrared radiations. All the planets of this sister solar system fall in its temperate zone with surface temperatures ranging from 0 – 100 degree celsius, plus because of their close orbits they are suspected to be tidally locked with the star, that means the same face stares at the star for all times, like our own moon with respect to Earth or moons of Jupiter with Jupiter, these factors hint us that there indeed might be liquid water on these planets and possibly some life-form.
Where our sun is expected to run out in a few billion years, due to its low consumption of the hydrogen furl, the TRAPPIST-1 star is expected to stay alive for 10 trillion years which is 700 times the age of the Universe itself. Thus, even if life hasn’t developed yet in any of the planets, it is quite probable that it might eventually evolve under the right favourable conditions, and so these exoplanets are potentially habitable.Of all these, the fifth planet, which has a sort of a pinkish hue, is the best candidate, whereas we know almost nothing about the seventh planet, which is suspected to be an icy planet, because it has revolved just once around its host star. The revolution period of other stars ranges from 1/5 days for the first planet to 13 days for the sixth planet.
The discovery is titanic in the sense that it is rare to find so many potential life supporting planets in one system, with so near-perfect conditions to support life. The European Space Agency called this one of the most incredible star system yet. The fact though is that for every one exoplanet we discover there are 100 that go unnoticed because of their size or that they don’t cross their host star and cannot be detected, but still, this solar system TAPPIST-1 can be our best shot yet, to find neighbours in our colony of Galaxies. With the switching ON of the NASA’s James Webb Space Telescope in 2018 which will measure the composition of the planets and their atmosphere more accurately and the European Space Organization’s Extremely Large Telescope in 2024 which will be capable of detecting water we are on the way to make greater discoveries about our cousins, and probably about the existence of many others.
So though there might still be some time before you could welcome your neighbours with some delicious cookies, it probably wont be long before you can know about their existence. Feel free to plan your vacations already! Happy Reading!
-The Cosmogasmic Person
LINKS THAT MIGHT INTEREST YOU :-
360 degree view of Planet TRAPPIST-1d : Video: 360 view of Planet 1d
Know more about Exoplanets : NASA : Exoplanets