NASA announced a huge cooperative effort to analyze other worlds for possible life this week.
The Nexus for Exoplanet System Science, or NExSS, will bring together scientists from three different NASA research centers, the SETI Institute and teams at 10 different universities. The initiative is the agency's first foray into looking for extraterrestrial intelligence in years.
NASA hasn't funded that goal since 1992, when it deployed the High Resolution Microwave Survey to search for extraterrestrial transmissions. Congress killed its budget less than a year later. The nonprofit SETI Institute has maintained the search since, using independently funded tools such as the Allen Telescope Array.
But NASA's new NExSS initiative is focused more on life than intelligent life, using verifiable scientific data from a relatively new field: the study of exoplanets, which orbit stars other than our own.
The Kepler mission launched in March of 2009 and really opened the floodgates. Since it started scanning distant stars, researchers have compiled a list of more than 1,000 confirmed exoplanets, plus thousands of additional candidates.
In fact, some research based on gravity data now indicates there's at least one exoplanet for each star in the Milky Way. Researchers found "stars are orbited by planets as a rule, rather than the exception."
But the mere presence of a planet doesn't mean much. Finding Earth-like life on another planet would require that planet orbit within its star's habitable zone, a certain set of distances at which water on the surface is a liquid.
There are a number of other variables to consider as well, which is where the brain trust at NExSS comes in. The goal is to develop a sort of equation to evaluate a given exoplanet for the possibility of life: a way to learn about and classify its formation, interior, geology, atmosphere, tidal dynamics, ecosystem and the effects of its host star.
At NExSS, Earth scientists will contribute their knowledge of how life works on our home planet. Planetary scientists will compare that Earth baseline to other worlds in our solar system. Heliophysicists will explain the interactions and effects stars have on their orbiting planets. And astrophysicists will give NExSS exoplanet targets to analyze using these rules.
Jim Green, NASA's Director of Planetary Science, says this "provides a synthesized approach in the search for planets with the greatest potential for signs of life. The hunt for exoplanets is not only a priority for astronomers, it's of keen interest to planetary and climate scientists as well."
NASA will keep NExSS well-stocked with data to sift through. Missionsover the next decade are expected to lengthen our list of exoplanets. The earliest dedicated mission, the Transiting Exoplanet Survey Satellite, is set to launch in 2017.