The first truly Earth-like alien planet is likely to be spotted next year, an epic discovery that would cause humanity to reassess its place in the universe.
While astronomers have found a number of exoplanets over the last few years that share one or two key traits with our own world — such as size or inferred surface temperature — they have yet to bag a bona fide “alien Earth.” But that should change in 2013, scientists say.
Exoplanets are piling up. Astronomers discovered the first exoplanet orbiting a sunlike star in 1995. Since they, they’ve spotted more than 800 worlds beyond our own solar system, and many more candidates await confirmation by follow-up observations. NASA’s prolific Kepler Space Telescope, for example, has flagged more than 2,300 potential planets since its March 2009 launch. Only 100 or so have been confirmed to date, but mission scientists estimate that at least 80 percent will end up being the real deal.
“The first planet with a measured size, orbit and incident stellar flux that is suitable for life is likely to be announced in 2013,” said Geoff Marcy, a veteran planet hunter at the University of California, Berkeley, and a member of the Kepler team. Marcy thinks this watershed find will be made by Kepler, which spots planets by flagging the telltale brightness dips caused when they pass in front of their parent stars from the instrument’s perspective. Kepler needs to witness three of these”transits” to detect a planet, so its early discoveries were tilted toward close-orbiting worlds (which transit more frequently). But over time, the telescope has been spotting more and more distantly orbiting planets — including some in the habitable zone.
Whenever the first Earth twin is confirmed, the discovery will likely have a profound effect on humanity. “We humans will look up into the night sky, much as we gaze across a large ocean,” Marcy told SPACE.com via email. “We will know that the cosmic ocean contains islands and continents by the billions, able to support both primitive life and entire civilizations.”
Marcy hopes such a find will prod our species to take its first real steps beyond its native solar system.
“Humanity will close its collective eyes, and set sail for Alpha Centauri,” Marcy said, referring to the closest star system to our own, where an Earth-size planet was discovered earlier this year. “The small steps for humanity will be a giant leap for our species. Sending robotic probes to the nearest stars will constitute the greatest adventure we Homo sapiens have ever attempted,” Marcy added. “This massive undertaking will require the cooperation and contribution from all major nations around world. In so doing, we will take our first tentative steps into the cosmic ocean and enhance our shared sense of purpose on this terrestrial shore.”
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