NASA has taken a momentous step forward in their quest to find life-sustaining planets outside our solar system, revealing the discovery of seven Earth-sized planets orbiting the same star. At the center of all this, quite literally, is something called TRAPPIST-1. So what is TRAPPIST-1 and how could it change our current understanding of the universe? The very official-sounding name actually refers to two very important things: the planetary system and the star that the planets orbit. The word TRAPPIST is, in fact, an acronym for the Belgian-operated telescope located in Chile that was used to first spot two of these exoplanets in May of 2016. "I felt super excited. Amazed by the very existence of the system... was kind of a shock," Michael Gillon, the Principal Investigator at TRAPPIST, explains in a video released by NASA. The Spitzer Space Telescope was able to confirm the existence of the planets originally found by TRAPPIST and went on to find five more planets to add to the system.
The TRAPPIST-1 system is located 40 light-years from Earth (considered relatively close to us — as our closest star system is a tenth of the distance). The size, mass, and densities of the planets were estimated using Spitzer data, revealing that at least six of the planets are likely to be rocky. Three of these planets are located close enough to the host star that they orbit in a "habitable zone" — an ideal location for a rocky planet to have water.
All seven planets are closer to the TRAPPIST-1 star than even our innermost planet Mercury is to our sun. One might think that this proximity would make it impossible for these planets to sustain-life, however, the TRAPPIST-1 star is quite different to our solar system's sun. According to reports, at the center of the TRAPPIST-1 system is a dim ultra-cool dwarf star, much smaller than our own. The planets could support liquid water, even orbiting at such a close range, as their sun is approximately half as warm as our own and less than one-eight of the width (making it on par with Jupiter). It is thought that the planets closest to the star are "tidally locked" to their host star due to the intense gravitational pull. Unlike our own planet, one side of the TRAPPIST-1 planets could be submerged in perpetual night while the other sees never-ending light.
The record-breaking results were published in the journal Nature on Feb. 22, exciting the scientific community. “This discovery could be a significant piece in the puzzle of finding habitable environments, places that are conducive to life,” said Thomas Zurbuchen, associate administrator of the agency’s Science Mission Directorate in Washington, said in a press release. “Answering the question ‘are we alone’ is a top science priority and finding so many planets like these for the first time in the habitable zone is a remarkable step forward toward that goal.”
While more research is needed to give us a better idea of the make-up of these exoplanets, when the James Webb telescope launches in 2018 scientists will be able to give us insights into the atmosphere of the planets, as well as their temperatures and surface pressures.