The US National Aeronautics and Space Administration (NASA) has announced that its planet-hunting Kepler Space Telescope has discovered 1,284 new exoplanets, nine of which orbit in their sun's habitable zone.
“This announcement more than doubles the number of confirmed planets from Kepler. This gives us hope that somewhere out there, around a star much like ours, we can eventually discover another Earth,” said Ellen Stofan, chief scientist at NASA Headquarters in Washington on Tuesday.
Kepler had previously identified 4,032 potential planets beyond our Solar System. The new verification shows that for 1,284 objects of these candidates, the probability of being a planet is well over 99 percent, the minimum percentage required for a celestial object to be recognized as a planet.
It is likely for an additional 1,327 of other candidates in the group to be real planets, but so far they do not reach the 99 percent threshold and they need to be studied more. Another 707 candidates, spotted by the cutting-edge telescope, are likely to be other astronomical objects rather than being actual planets, according to the analysis.
The analysis also revalidated the remaining 984 objects in the list, which were previously verified through other means as actual planets.
“Before the Kepler space telescope launched, we did not know whether exoplanets were rare or common in the galaxy. Thanks to Kepler and the research community, we now know there could be more planets than stars,” said Paul Hertz, Astrophysics Division director at NASA Headquarters, adding, “This knowledge informs the future missions that are needed to take us ever-closer to finding out whether we are alone in the universe.”
The new research also reveals that out of the 1,284 objects, about 550 could be rocky planets, like our Earth.
Launched in March 2009, Kepler spots potential planets by detecting their transit signals when they pass in front of their host stars. The passage causes a slight dip in the star’s luminosity, which can be detected by Kepler’s sensitive eye, to determine the object’s size, orbital period and mass.
A close and rare transiting phenomenon occurred on Monday when Mercury glided between the Sun and the Earth.
Astronomers hope that by finding a rocky planet in the habitable zone of its host star, humans can colonize it as their second cosmic home, and by detecting extraterrestrial (intelligent) life on it, our cosmic solitude could be refuted.
The habitable zone by definition is the area around a star where rocky planets have surfaces warm enough, with sufficient atmospheric pressure, to keep water in its liquid form, a key ingredient to life as it is known on Earth.