With more than 800 exoplanets identified since 1995, many astronomers are predicting that 2013 will be the year that the first truly Earth-like planet is spotted, reports Space. Scientists have gotten ever closer to finding an alien Earth in recent years, identifying several in the right temperature range and others close to our size; but none has yet put together all of Earth's features. But with 200 billion stars hosting at least 50 billion planets in the Milky Way alone, astronomers think it likely there are many Earth-like satellites out there. "Assuming that 1:10,000 are similar to the Earth would give us 5,000,000 such planets," wrote one scientist.
As for how we might discover that alien Earth, the smart money is on the Kepler telescope, which has already spotted 2,300 potential planets since being launched in March 2009. But once we identify an Earth twin, then what? Many scientists hope it could inspire humanity to venture off our planet and deeper into space. "We humans will look up into the night sky, much as we gaze across a large ocean," said another astronomer. "We will know that the cosmic ocean contains islands and continents by the billions, able to support both primitive life and entire civilizations." (Read more astronomy stories.)