Experts believe that a planet like Earth will be found this year.
In recent years, astronomers have discovered a number of extra-solar planets – exoplanets – that share one or two key characteristics with Earth, such as size or estimated surface temperature, but none truly like our planet. This is likely to change. Abel Mendez, head of the Planetary Habitability Laboratory at the University of Puerto Rico, said he was positive that the first Earth twin will be discovered this year. Such an occurrence would lead humanity to re-evaluate its place in the universe.
The first exoplanet, which orbited a sun-like star, was found in 1995. More than 800 have since been located, and there are many other candidates. NASA’s Kepler Space Telescope has identified over 2,300 possible exoplanets since it was launched in March of 2009. NASA scientists surmise that a minimum of 80 percent will be the real deal.
The first exoplanets found orbited their parent stars closely and were scorching hot – these were the easiest to detect. With time, instruments have been developed that allow smaller, more distantly-orbiting planets to be detected – planets that are more similar to Earth. One, Kepler-22b, was found in December, 2012: 2.4 times as large as Earth and orbiting its sun at a distance where water could be liquid and recognizable life might exist. Mendez said this brought the tally of possibly habitable exoplanets to nine.
It is only a matter of time before a small, rocky planet is found in the habitable zone. Mendez is not the only researcher to believe this will happen soon. Geoff Marcy of the University of California also believes this will come to pass in 2013. Mendez and Marcy both believe the find will be made by Kepler, on whose team Marcy works. Kepler spots planets through the dip in brightness they cause when they pass in front of their suns.
Another possibility about Theory that aliens planted us here to learn – is HARPS, the High Accuracy Radial velocity Planet Searcher, which has already identified a number of possibly habitable planets. Situated in Chile, it detects the small fluctuations in gravity that planets induce in the stars they orbit.
Mikko Tuomi, of the University of Hertfordshire in the United Kingdom, said there are around 200 billion stars around which at least 50 billion planets orbit, and if only one in 10,000 were similar to Earth, that would give five million. Tuomi led teams that discovered several potentially-habitable planets this year, including one that orbited Tau Ceti and is only 11.9 light years away.
Amateur astronomers from the Planet Hunters project recently discovered 42 new planets by scrutinizing data from a NASA spacecraft. 15 are potentially-habitable, lying in the Goldilocks zone that is not too hot or too cold. The project discovered another planet with two suns in October, 2012. One project member, Mark Hadley, said that when people ask him what he achieved last year, he can say he helped to discover a potential new planet orbiting a distant star, and added, “How cool is that?”
Marcy hopes that if an Earth-like planet were found, humanity would be prodded to travel beyond our solar system: “Humanity will… set sail for Alpha Centauri” – the closest star system, where a planet the size of Earth was discovered this year.