Think back, either to the distant past or if you are a Star Wars buff like myself then to just last week, to Star Wars Episode IV: A New Hope. Immediately before the intro scrolls through, disappearing somewhere in the Universe to eventually get sucked up by a black whole, is the striking line, ‘A long time ago in a galaxy far, far away…’ Bear in mind I was probably about 10 when I first saw the movie, but this was the first time I ever truly considered my place in the infinity that is time and space. Before that moment it had never occurred to me that a technologically advanced society could exist in the past or that we that we may be the alien race. That one line easily encapsulates the idea that life is evolving so very far away from us that we may never know of its existence; and that the vastness of time and space is such that innumerable quantities of life forms could have risen up and extinguished long before we made our debut. Mind blown.
It’s easy for us to imagine ‘life’ as an approximation of ourselves, something humanoid and just as violent. When you hear NASA officials proclaim that they will identify life in the Universe in the next 20 years, you think The Day the Earth Stood Still, Independence Day, or that one with the giant ant-like creatures that an army of kids obliterate. What they are talking about is something entirely different. They are looking for planets that can harbor life much like our own, planets that are just far enough from a star, and are made up of just the right compounds with a hospitable atmosphere. A planet where little amoebas are swimming around in frozen lakes or deep in oceans where the heat from inside the planet is steaming out of vents. They are looking for signs of life, for the possibility of life on another planet.
Right now, the Kepler satellite is searching the Universe for exoplanets, with a special interest in ‘Earth-like’ planets. To qualify, the planet has to be one-half to twice the size of Earth, and be close enough to a star to contain liquid water along with temperatures where life can flourish. It’s a lot like Goldilocks and the Three Bears, all the conditions need to be just right. Since 2009, Keplar has discovered 1,019 exoplanets, 30 of which fall in the potentially habitable category. The planets are so distant that deducing all of the conditions on the surface is not yet possible. The planets are discovered by measuring the brightness of a star over time and calculating if the brightness dips. While the satellite is measuring a star, any object that passes between that star and the satellite will reduce the measured brightness. This will continue to occur at regular intervals as the object orbits the star. Combined with supporting evidence, scientists can then reasonably assume that it is an exoplanet.
The next satellite to join in the search for suitable exoplanets is TESS, short for the Transiting Exoplanet Survey Satellite, set to launch sometime in late 2017. The TESS mission will detect small planets that orbit bright stars; during its two year mission, it will monitor more than 500,000 stars for transiting exoplanets, discovering an estimated 3,000 candidates. The James Webb Telescope, which launches in 2018, will help characterize these planets in more detail as just knowing the planets are there and estimating their mass is not enough to know if all the conditions for life are present. It will take a host of supporting satellites, sensors and scientists to detect the potential for life. NASA is bringing together scientists from multiple disciples to the Nexus (win for the Star Trek reference!) for Exoplanet System Science. This collaboration will include astrophysicists, earth scientists, heliophysicists and planetary scientists all using their expertise to identify which planets are most habitable. This meeting of the minds will help establish models and procedures as new technologies surface and more exoplanets are discovered. There is still a chance that we will discover life on other planets in our lifetimes, helping to answer one of humanity’s fundamental question: Are we alone?