The first "alien Earth" planet is likely to be spotted next year, according to astronomers.
An epic discovery that would cause humanity to reassess its place in the universe, the feat is believed to be possible, even likely, by scientists in 2013.
Researchers have honed in on a number of exoplanets in recent years that share key traits with our own world, such as size or inferred surface temperature.
They have yet to bag a bona fide "alien Earth." But just wait, scientists say.
"I'm very positive that the first Earth twin will be discovered next year," said Abel Mendez of the Planetary Habitability Laboratory at the University of Puerto Rico.
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 in under three years since its March 2009 launch.
Only 100 or so of those 2,300 have been confirmed to date, but mission scientists estimate that at least 80 percent will end up being the real deal.
Over time, new instruments came online and planet hunters honed their techniques, enabling the discovery of smaller, more distantly orbiting planets.
In other words, like this one.
A planet must be within its star's habitable zone - that just-right "Goldilocks" range of distances where liquid water, and perhaps life as we know it, can exist.
None of the worlds found yet are true Earth twins. The handful of Earth-size planets spotted to date all orbit too close to their stars to be suitable for life.
But it's only a matter of time before a small, rocky planet is spotted in the habitable zone, and researchers think that time is nigh, based on several factors.
Continue reading about the search for Alien Earth!