First Earth-like planet to be spotted in 2013?
While astronomers found exoplanets in the last few years that share key characteristics with our own world, a true "alien Earth" has yet to be found, Space.com reported.
"I'm very positive that the first Earth twin will be discovered next year," Abel Mendez of the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo told Space.com (http://www.space.com/19044-alien-earth-exoplanets-2013.html).
Geoff Marcy, a veteran planet hunter at the University of California Berkeley, echoed Mendez's optimism.
"The first planet with a measured size, orbit and incident stellar flux that is suitable for life is likely to be announced in 2013," Marcy said.
Mikko Tuomi, of the University of Hertfordshire in England, told SPACE.com there are about 200 billion stars that host at least 50 billion planets.
"Assuming that 1:10,000 are similar to the Earth would give us 5,000,000 such planets," Tuomi said.
Tuomi had led teams reporting the discovery of several potentially habitable planet candidates this year, including an exoplanet orbiting the star Tau Ceti just 11.9 light-years from Earth.
"So I would say we are talking about at least thousands of such planets," Tuomi said.
Both Mendez and Marcy believe the find will be made with the help of the National Aeronautics and Space Administration's Kepler Space Telescope.
Kepler spots planets by detecting dips in brightness caused when the planets pass in front of their parent stars.
Since its launch in March 2009, the space telescope has flagged more than 2,300 potential planets, though only about 100 have been confirmed to date.
Astronomers discovered the first exoplanet orbiting a Sun-like star in 1995.
They have since spotted more than 800 worlds beyond our own solar system.
While the first exoplanets found were hot Jupiter-like worlds, Kepler found a planet 2.4 times larger than Earth orbiting in its star's habitable zone last December.
The planet Kepler, named Kepler-22b, had the "right" range of distances where liquid water, and possibly life as we know it, can exist.
Mendez estimates the Kepler team and other research groups have detected at lesat nine potentially habitable exoplanets.
Yet, none of those in Mendez' Habitable Exoplanets Catalog are small enough to be true Earth twins as the Earth-size planets spotted to date all orbit too close to their stars to sustain life.
Aside from the Kepler telescope, the High Accuracy Radial velocity Planet Searcher (HARPS) at the European Southern Observatory in Chile has also spotted a number of potentially habitable worlds.
"HARPS should be able to find the most interesting and closer Earth twins ... A combination of its sensitivity and long-term observations is now paying off," Mendez said, adding many Kepler planets are too far away to characterize in detail.
Effect on humanity
Space.com said that once the first Earth twin is confirmed, it 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. We will know that the cosmic ocean contains islands and continents by the billions, able to support both primitive life and entire civilizations," Marcy said.
Marcy voiced 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.
He added the small steps for humanity will be a giant leap for our species, adding robotic probes to the nearest stars "will constitute the greatest adventure we Homo sapiens have ever attempted."
But he said 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," he said. — LBG, GMA News