New interesting information arrives regarding the big discovery with the U.S. space telescope Kepler of the two new exoplanets similar to Earth outside our solar system with the greatest similarity to Earth ever recorded and where life could potentially exist, according to astronauts.
"From what can be observed, their radius and length of their orbits around their star set apart, these are the two exoplanets are the most similar to Earth objects ever found", said Justin Crepp, an astrophysicist at the University Of Notre Dame, one of the co-authors of this discovery published in the American journal Science.
Kepler-62f is thus most similar to Earth in size, and is located in the habitable zone of another star and which rock composition probably has never been detected. It revolves around its star (Kepler-62) in 267 days.
Kepler-62e, which orbits its star in 122 days, is in the limit of the distance space where the temperature is neither too hot nor too cold to allow water to exist in liquid form, specify these astronomers. The star Kepler-62, located at 1,200 light-years from Earth (one light year is 9.460 billion kilometers) is called dwarf with a mass representing two-thirds of our sun. It is only 20% as bright.
These two exoplanets are the furthest from the star among the five planets of the system and receive similar sun radiation than Venus and Mars.
Their size suggests that these two exoplanets are rocky like Earth or formed of water ice According to previous research, planets with a radius less than 1.6 times than the Earth have a density consistent with a rocky composition.
These astronomers have also found another exoplanet (Kepler-69c) in orbit in the habitable zone around a star similar to our sun called Kepler-69, but 70% larger than the Earth and whose composition remains unclear.
A matter of time If they do not know if life could exist on both rocky planets they believe that the quest for a sister planet of Earth orbiting a star like the sun tightens.
"The discovery of these rocky planets in the habitable zone brings us closer to the moment we could find a planet like ours", said John Grunsfeld Thursday, the head of NASA science missions.
"It's only a matter of time before we know if our galaxy is home to a multitude of planets like Earth, if we are a rarity", he adds.
In late 2011, NASA confirmed the discovery of the first exoplanet in the habitable zone of a star system, called Kepler 22b, orbiting a star (Kepler 22) located about 600 light-years.
But given its large size, with a radius multiplied 2.4 times than the Earth, its composition is very uncertain.
Astronomers detect exoplanets by measuring the decrease in brightness of the star when planets pass by. Launched in 2009 by NASA, the Kepler telescope scans over 100,000 stars like our sun located in Cygnus and Lyra constellations. Its mission is to search for planets sisters to Earth which could harbour life in our galaxy, the Milky Way.
Kepler has so far detected 2,740 potential exoplanets which 122 were confirmed to the day using telescopes and other equipment "Kepler provides a resurgence of discoveries in astronomy and we are making excellent progress to determine if planets like ours are the exception or the norm in the Milky Way, said William Borucki, Kepler chief scientist.