by: Chris Thompson
NASA’s latest announcement in the search for Earth-like planets is the stuff dreams are made of….
In a win for exoplanet seekers and exterrestrial life hunters everywhere, NASA yesterday announced the discovery of not one, but seven new planets. These exo-worlds, orbiting an ultra-cool dwarf star named TRAPPIST-1, and located thirty-nine lights years from Earth, are unique in that several of them reside in the so-called “Goldilocks” habitable zone, a region of space around a sun where a rocky planet is most likely to have liquid water. For comparison, our sun’s habitable zone encompasses the orbits of Venus and Mars, with our two sister planets falling just on the zone’s edges. Because of this fact, Venus is too hot to have liquid water and Mars is too cold, however our homeworld, Earth, resides in that region of space that is just right for water to pool. Throw in the fact that on Earth, where there is water there is life, be it at extreme temperatures and crushing depths deep underwater, or in the coldest, darkest reaches of the planet, and NASA’s announcement begins to look downright exciting. Furthermore, what makes this report such a watershed moment in the hunt for exterrestrial life, is the fact that not only are there potentially seven rocky, Earth-like worlds orbiting a relatively nearby star, but three of these exoplanets fall directly in the habitable zone where liquid water could exist. With water molecules being crucial to the functioning of most known life forms on Earth, and with the newfound knowledge that the worlds circling TRAPPIST-1 could possess it in liquid form, the potential for discovering new forms of life, and laying to rest mankind’s eternal question of whether or not we are alone in the universe, now seems entirely more plausible.
The question about humanity’s place in the cosmos has confounded our race for centuries. It’s right up there with such lofty questions as ‘Is there a god?’ or ‘Do we possess a soul?’ or ‘Why is there something instead of nothing?’ Any opportunity to move the answers to these fundamental questions even marginally forward has the potential to not only upend, but radically change humanity’s path, and in the best case scenario, provide our race with hope for its own future. Enter NASA’s Spitzer Space Telescope in 2016, an infrared telescope that trails Earth as it orbits the sun. It’s a space-based telescope uniquely well-suited for studying a star like TRAPPIST-1, whose light glows strongest in the infrared. Observing the star’s light continuously for five hundred hours, Spitzer was able to not only confirm previous data suggesting the presence of two habitable zone planets orbiting the ultra-cool dwarf star, but find five additional planets orbiting in a similar range. By keeping its long, unblinking eye trained on TRAPPIST-1, and with its sensitive infrared optics measuring the minute dips in light as these seven planets transited (or crossed) the path of their sun, Spitzer was able to obtain data sets that not only proved the existence of the exoplanets, but hinted at the masses of the worlds, thus allowing their densities to be estimated.
With Spitzer’s density data hinting that six of the seven worlds are rocky in nature, like Earth, and with studies on the architecture of the exoplanets orbits suggesting that they all were closer to TRAPPIST-1 than our own Mercury is to our sun, the question begs to be asked: ‘What are these planet’s like?’ The first suggestions to their nature lie in the orbits of the worlds. All seven of them appear to be relatively nearby to each other, circling at such close distances that if an individual were standing on one of the exoplanets, let’s say TRAPPIST-d, they would be able to gaze up into the night sky and quite possibly make out the features of several of the other worlds simultaneously. Another curious aspect of the planets is that the data suggests that they may be tidally locked with TRAPPIST-1, like our own Moon is to Earth, showing only one face to their sun at all times. While TRAPPIST-1 is merely an ultra-cool dwarf sun, with a maximal temperature half that of our own Sol, its net radiated heat still presents an opportunity for unique weather patterns on its worlds never before encountered on Earth. With one side of these tidally-locked planets perpetually bathed in darkness and the other side perpetually bathed in light, extremes in temperature across these worlds are a given. And at the transition line from perma-day to perma-night, let’s call it the Land of Eternal Sunset (the best location for a thin ring of life to exist), the existence of powerful wind patterns and the transport of massive amounts of water generated by such differences in thermal energy would truly be an amazing sight to study and behold.
To NASA’s credit, Spitzer isn’t the only space telescope in the game studying the wonders of TRAPPIST-1’s seven exo-worlds. The last satellite of NASA’s Great Observatories program, Spitzer joins the ranks of one of its elders in the program, the Hubble Space Telescope, and a new generation of space-based observatories, the planet-hunting Kepler Space Telescope (already credited with discovering an astonishing 2,231 exoplanets, with an additional 2,365 awaiting confirmation!) in helping to unlock the mysteries of this exciting planetary system. Already well into the screening process, Hubble has initiated studies on four of the exoplanets, three of them falling within the habitable zone, in the hopes of determining if these planets possess atmospheres that are hydrogen-dominated, and “puffy” in nature, which would suggest that they are gaseous (like our own Neptune or Jupiter) or truly Earth-like and rocky. Having confirmed that TRAPPIST-1’s two innermost planets are indeed rocky, Hubble’s final confirmation that the planets falling within the star’s habitable zone are similar to Earth in make-up would be a major discovery. According to Nikole Lewis, co-leader of the Hubble Telescope study and an astronomer at the Space Telescope Science Institute, “The TRAPPIST-1 system provides one of the best opportunities in the next decade to study the atmospheres around Earth-size planets.”
With additional observations of these worlds sure to reveal more of its wondrous secrets, and with the impending launch in 2018 of NASA’s premier, bad-ass space observatory, the James Webb Space Telescope, it will only be a matter of time before we can tease out their suitability for habitation. Sensitive enough to sniff out the chemical components of a planet’s atmosphere, including water and oxygen, and with instruments capable of analyzing a planet’s temperature and surface pressure, the James Webb era of space-based observation has the potential to build-off of the discoveries of the mighty telescopes that came before it, and move the answers to some of humanity’s most lingering questions boldly forward. I for one, cannot wait to see what the future has in store.
View many more images, as well as several videos, in an extensive multimedia gallery highlighting this tremendous discovery here!!