Even as astronomers work toward the hotly anticipated milestone discovery of an Earth-like twin orbiting another star, researchers are already asking what it will take to detect the existence of extraterrestrial life on such a planet.
First, the bad news: No telescope in existence seems to have the observing power to pick out the kinds of molecular signals that would indicate an exoplanet is habitable or even inhabited. On the bright side, observatories now being planned or already under construction could have a shot. But it’s hardly a lock.
The next generation of giant, ground-based telescopes, generically known as extremely large telescopes (ELTs), may be able to tease out biomarker signals from the starlight filtering through exoplanetary atmospheres, according to research recently published in The Astrophysical Journal and forthcoming in the journal Astronomy & Astrophysics. The two groups of scientists calculated what possible biomarkers might be detectable with the European Extremely Large Telescope (E-ELT), a planned observatory with a 39-meter primary mirror that would dwarf the 10-meter twin Keck telescopes now on the cutting edge of astronomy. (The Kecks can breathe easy for now: E-ELT will not come online until the 2020s at the earliest.) The results are cause for cautious optimism: assuming that Earth-like planets are relatively common, the E-ELT or a comparable observatory might be able to identify several molecules important to, or even indicative of, life.
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