December 31, 2012
Astronomers Believe 2013 Will Be Record Year For Habitable Planet Discoveries
Lee Rannals for redOrbit.com — Your Universe Online
While 2012, like most years, held some significant findings, 2013 could be one for the record books when it comes to looking for habitable planets.
Scientists discovered the first exoplanets in 1995, and since then there have been around 800 discovered.
Although many exoplanets that sit in that "Goldilocks" (habitable zone) have been discovered, they aren't quite the "Earth twin" scientists are hoping to find.
NASA announced in December that its Kepler Project astronomers have confirmed the first planet known to orbit a Sun-like star in the habitable zone, which is the distance between a star and a planet in which liquid water is able to exist.
The planet, Kepler 22b, has twice Earth's gravity, and is more than twice its radius. It is also about 600 light years away from Earth. While this planet has the potential to hold liquid water, thus also alien life, what lies down on Kepler 22b's surface is still a mystery.
Another team of astronomers announced the discovery of Tau Ceti, which is another planet that lies in this zone and is just 12 light years away.
While so far no one has confirmed that there is an "Earth twin" out in the black of space, astronomers are coming closer and closer to hitting this discovery, or an equivalent one.
The importance for finding these Earth twins, versus planets that just lie in the right distance from their star, involves a lot of variables.
Caleb A. Scharf wrote for Scientific American that some of these planets could be "appallingly hostile," featuring high-pressure, high-temperature climates and those in a sub-arctic category with thin atmospheres.
Scharf describes finding a true "Earth-like" planet is described as the Holy Grail for exoplanetary science. He said that it might just be that there are no other places quite like Earth. However, while the uniqueness of Earth is something to consider, Scharf also points out that the chemistry of the universe does seem to be the same throughout.
He hypothesizes that there may be no "Earth-like" planets out there, but there could be "Earth-equivalent" worlds.
"So, we should not necessarily hold our breath for other Earth-like planets, but we should expect an astonishing diversity of equivalent places," Scharf wrote. "I for one can´t wait to find out how the complex rough and tumble of molecular evolution played out on those other worlds."