There has been a discovery of an Earth size planet orbiting a nearby star at a distance that would make life comfortable there.
A newly discovered exoplanet, named Gliese 581 G, would be the first Earth-like world found in a habitable zone, where a planet's temperature can sustain liquid water.
In addition, the planet's discoverers are confident that life will be found there in the future.
According to Steven Vogt, a professor of astronomy and astrophysics at the University of California, Santa Cruz. "given the ubiquity of life and the propensity for life to thrive wherever it can, I believe that there is a 100 percent chance that life can exist on this planet." He said, "I have almost no doubt about it."
The team discovered two newly discovered planets orbiting Gliese 581, a red dwarf star. It lies in the constellation Libra, 20 light-years away from Earth. Light years are approximately 6 trillion miles (10 trillion kilometers).
It is estimated that red dwarf stars are about 50 times fainter than our sun. Because these stars are cooler, their planets can orbit closer to them and still remain habitable.
In just under 37 days, Gliese 581 G can complete its orbit around its star at a distance of 0.15 astronomical units. Earth and the Sun are approximately 150 million km (93 million miles) apart, which is one astronomical unit.
Six planets orbit their star in nearly circular paths in the Gliese 581 planet system.
The researchers estimate that Gliese 581 G has a mass three to four times that of Earth. According to the mass and estimated size, the planet is probably rocky with enough gravity to retain an atmosphere.
The planet is tidally locked to its star, so that one side basks in perpetual daylight and the other remains in darkness. The locked configuration stabilizes the surface climate of the planet.
Depending on the side facing the sun and the side facing the dark side, the average surface temperature may vary between 24 degrees below zero and 10 degrees F (minus 31 to minus 12 degrees C).
Several habitable worlds have been found and later discredited, so what makes this one so special?
It's still possible that further observations of this planet will shed more light on it. Researchers in their journal article point out that radial velocity has become more accurate over time.
Seager also points out that the researchers didn't make some of the unrealistic assumptions made in the past.
Gliese 581 C, another planet that orbits Gliese 581, was also thought to have suitable temperatures for life. However, the researchers had calculated the amount of energy the planet reflected in an "unrealistic" way, Seager pointed out. For this discovery, no such estimate was made.
"We're looking at this one as basically the tip of the iceberg, and we're expecting more to be found," Seager said.
In order to make this a reality, the researchers recommend building six to eight meter Automated Planet Finder telescopes in each hemisphere.
The Milky Way has billions and billions of stars beyond the 100 closest to Earth. With that in mind, the researchers suggest there could be tens of billions of potentially habitable planets out there.
Researchers suggest that tidally locked planets that orbit the habitable zones of red dwarfs, such as Gliese 581 G, are likely to harbor life.
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