The James Webb Space Telescope, expected to launch in 2018 (image above), will have the ability to search for the chemical signatures of life in alien atmospheres, however, we're not sure how life begins or how pervasive it is, making it very difficult to pinpoint when and where to find it, scientists said during a session at the National Space Symposium held last week in Colorado Springs. "We don't know how many planets we're going to have to examine before we find life, and not finding it on 10 or 100 doesn't mean it's not there," John Grunsfeld, NASA's associate administrator for the science mission directorate said during the panel. "This may be very tricky." "We can't really tell what life is," MIT astrophysicist and exoplanet hunter Sara Seager said. "All we can do is work with what life does. Life metabolizes and generates gasses, so that's what we're looking for … The good news is, whatever life is, as long as it uses chemistry, we're all set. We'll have the capability to find it
and we'll have that capability within a decade with James Webb and hopefully within two decades with an Earth twin, but beyond that, it's really just up to chance."
"I think it's fair to say that we just want to see one example," Seager said. "If we see one, we almost know that it's everywhere because we need to be reassured, we need confidence that life is actually ubiquitous."
After the two successful space telescopes CoRoT and Kepler were decommissioned this year, planet hunters are now hopeful with regard to the pending decision on the PLATO mission. PLATO (Planetary Transits and Oscillations of Stars) will build on the experience of CoRoT and Kepler in the search for planetary systems around nearby bright stars, and thus allow for extensive follow-up observations. This could allow the determination of the radius (as in the system KOI-351) and the mass of the planets, as well as a first look at the composition of the planet.
Furthermore, it would even be possible to examine the atmosphere of the planets in such systems, which may give rise to indications of the activity of living organisms. This would be a major breakthrough in search for a ’second Earth’. The European Space Agency will make a decision on the PLATO mission in early 2014.
Until now, 771 stars with planets have been identified. However, most of the exoplanets discovered so far are ’solitary’. Only 170 stars are known to be orbited by more than one planet. Large planetary systems are the exception – not because they do not exist, but because they are particularly difficult to detect and characterise.
More via The Daily Galaxy.