Perhaps the most important question our species can answer is whether or not we are alone in the Universe. It has been speculated that nearby planetary bodies such as Mars or Titan may have evidence of extraterrestrial life, but technological progression is slow and it may be years or even decades before we have the ability to find out for sure. In the mean time, NASA has been using the power of advanced telescopes such as the Spitzer Space Telescope or the James Webb Telescope (set to launch in October of 2018) to analyze planets outside of our solar system for evidence of life.
On Wednesday at 1PM, NASA held a live press conference to announce their newest discovery – the Spitzer Space Telescope has discovered seven Earth-sized planets orbiting TRAPPIST-1, a nearby sun only 40 light years away. But what may be even more exciting is that three of these planets lie in the habitable zone of the star, meaning it is possible we could find liquid water or even life.
“This discovery could be a significant piece in the puzzle of finding habitable environments, places that are conducive to life… 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.”
– Thomas Zurbuchen, Associate Administrator of the Agency’s Science Mission Directorate in Washington
How was this discovery made?
Modern telescopes are nowhere near powerful enough to be able to see these planets through a lens. Instead, the Spitzer Telescope measures the brightness of a sun over a long period (in this case 27 days) and detects when the brightness of the sun dips. This correlates with when an object is passing in front of the sun, momentarily blocking some of it’s light. In 2016 it was announced that three exoplanets had been found in this system, however after analyzing this new data over 27 days they found thirty four transits, showing that there are actually seven planets.
By analyzing the way in which these planets were pulling on each other through gravity, NASA scientists were able to detect not only the size of these planets but the mass, thereby giving them the ability to estimate the density as well. According to the data, they are likely to be rocky. In addition, three of the TRAPPIST-1 planets lie within the habitable zone of the star, receiving a similar amount of sunlight as the Earth.
It has yet to be confirmed whether or not there are large bodies of liquid water on these new worlds, but with the launch of the James Webb Space Telescope next year, it is quickly becoming possible for us to answer these questions. Within the next few years we should know whether or not these planets have water, and their atmospheric composition may be known by the early 2020s.
Why is this significant?
Potentially habitable planets have been found before, but the planets of TRAPPIST-1 are much closer to Earth and thereby much more easily observable for NASA’s telescopes. This discovery drastically improves our ability to study exoplanets and answer once and for all whether or not we are alone in the universe. While it is impossible for us to directly travel there anytime soon (we’re talking millions of years of travel with our current technology), we don’t even need to do so in order to understand what these planets are like.
But why does it matter if we discover life at all? How will that change the lives of people living here on Earth? One word – perspective. Human’s have only ever communicated with other members of our biological family. While you may believe that you’re ready to meet an alien, I assure you that the reality would be much more impactful than you could imagine. The discovery of extraterrestrial life would shake human culture to it’s core. The implications bring into question every facet of our worldview from religion, to politics, to philosophy – and this discovery is a giant leap in the right direction.