By: Talia Ho, SPECTRUM Writer
Have you ever dreamt of life outside of Earth? The idea of alien life has captivated the imaginations of millions through television and movies. It seems like everyone has met someone with a UFO or alien abduction story. Extraterrestrial life isn’t just important in the media, though. Thomas Zurbuchen, associate administrator of NASA’s Washington Science Mission Directorate, states that “…answering the question ‘are we alone’ is a top science priority.” NASA’s recent discovery may bring humanity one step closer to answering that question.
On February 22, 2017, NASA announced the discovery of seven exoplanets that are about the same size as Earth, orbiting around a single star. Exoplanets are planets outside of our solar system, and they are not uncommon. But what makes them special is their potential for life. Liquid water is essential to life as we know it, and three out of seven planets lie in their sun’s “habitable zone,” where conditions are right for liquid water to exist.
The system these planets are in is called TRAPPIST-1, named after the Transiting Planets and Planetesimals Small Telescope. Researchers using TRAPPIST in 2016 found three small planets in the system. Several ground based telescopes were used to confirm the existence of two, as well as finding five more planets. The planets are likely rocky, and further observations will confirm whether water exists on any of the planets.
The star at the centre of TRAPPIST-1 is a red-dwarf star, much cooler than our sun, allowing habitable zones to exist close to its vicinity. A single orbit around this habitable zone takes 1.5 days for the nearest planet. While red-dwarf stars make up over 75% of the stars in our galaxy, experts are still not sure whether their planets are generally suitable for life. One huge obstacle for the formation of life is that younger red-dwarf stars tend to release flares and bursts of radiation. While it may seem impossible for life to survive in such an environment, TRAPPIST-1 is relatively calm, and NASA’s current computer models can’t predict every single effect of solar flares on a planet. Life is vastly complex, and it is conceivable that lifeforms could find a way to survive even while blasted by radiation. If life exists within the TRAPPIST-1 system, it’s likely to be relatively simple. Victoria Meadows, the principal investigator for NASA’s Astrobiology Institute’s Virtual Planetary Laboratory, states that “the majority of life we find out there is likely to be single cell, relatively primitive life. That’s the sort of thing we’d be looking for on planets orbiting [stars like TRAPPIST-1].”
In the future, a number of different telescopes will be used to take a closer look at the TRAPPIST-1 system. It will take an estimated five years to understand the atmosphere of each planet, and figure out whether water (and potentially life) is present. While we wait, NASA’s artists have been busy replicating what the view might look like from the surface of TRAPPIST-1’s planets. Check it out: