In its latest edition to the catalog of exoplanets Nasa on Monday has introduced us to around 229 possible new exoplanets in our galaxy among which ten planets are relatively small, rocky and habitable planets much similar to our Earth. The Kepler space telescope was used while detecting those new members of the catalog.
The mission was started in order to find worlds beyond our own planet and a total number of 200,000 stars in the Cygnus constellation were being scanned in the very first effort.
After the last recent addition on Monday, the official catalog now contains 4,034 total candidates.
The list includes some tiny blips which are being assumed as the possibility of the existence of a planet around a star.
Of these, 49 fit squarely into their star's 'habitable zone' that Goldilocks region where liquid water can pool on the surface and life may be able to thrive.
Launch of the Keplar space telescope into orbit around the sun took place in the year 2009. The initiative was taken to get an idea of a small slice of the Milky Way in an effort to understand the demographics of our galaxy, to get answers of some most mysterious questions ever like How many stars are like our sun? How many of those host planets? How many planets orbit in the habitable zone? Is there any place else in this vast universe that living beings might call home? and many more.
Though a bunch of stars have already been detected it will take a bit more time to label some of those as 'Earth 2.0.'
Among 4,034 candidates, more than half have already been confirmed as exoplanets and Susan Thompson, the lead author of the catalogue study has confirmed the existence of 10 the new "Earth-like" planets found in their stars' habitable zones.
Several of these planets orbit G dwarfs, the same species of star as our own sun. And one, namely KOI 7711 is a possible twin of Earth having much similar features as our earth except its size. In terms of size only it is 30 times bigger than our Earth.
It's too soon to say whether KOI 7711 truly merits the label 'Earth-like,' Thompson cautioned. Kepler is incapable of determining whether an exoplanet bears an atmosphere or liquid water. If aliens were observing our solar system using a similar instrument, they might think it contained three rocky, potentially habitable worlds - Venus, Earth and Mars. "But I'd only want to live on one of them," Thompson said.
A second research group combined the Kepler data with measurements from ground-based telescopes to calculate the approximate sizes and compositions of 2,000 exoplanets. They found that smaller worlds, the kind that Kepler was designed to detect, fall into two distinct groups: rocky planets that could be up to 1.75 times the size of our own, called "super-Earths," and gaseous "mini-Neptunes," which lack a solid surface and are 2 to 3 times bigger than Earth. Nearly every star surveyed hosted a planet in one of these two categories. But, curiously, no planets straddled the divide. Each world was either smaller and rocky, or larger and gassy.
Benjamin Fulton, an astronomer at Caltech and the University of Hawaii at Manoa, compared the new categories to species of animal.
"Finding two distinct groups of exoplanets is like discovering mammals and lizards make up distinct branches of a family tree," he told reporters Monday. And just as discovering distinctions between species helps us understand evolution, this revelation could help astronomers determine how planets take shape.
Fulton and his colleagues believe that the sharp distinction between "super-Earths" and "mini-Neptunes" may be a result of how much hydrogen and helium contributed to their formation. These elements are extremely light and exist as gas at all but the lowest temperatures. Rocky worlds like Earth, with thin atmospheres and nice, firm surfaces, contain relatively little of these elements. Perhaps they started off with less, or perhaps the light elements were burned or blown away.
But according to Faltun "if a planet can hold onto just a bit more of these gases, it 'puffs up' like a balloon. Hydrogen and helium form vast, thick atmospheres around mini-Neptunes, making these worlds much bigger than their rocky counterparts.
It's difficult to know for sure, because our own sun doesn't host a mini-Neptune - unless you count the hypothesized "Planet Nine" that some scientists believe lurks at the outer edge of the solar system. (For the record, Fulton doesn't - not yet.) But researchers are bent on figuring out what leads a world to become rocky, rather than gassy, because as far as we're aware life can only take shape on solid ground.
Original mission of Keplar came to an end in the year 2013 when one of the wheels that helped to keep the spacecraft pointed toward the Cygnus constellation failed, so it could no longer scan the same small slice of sky. But by using pressure from light particles from the sun to stay oriented, the telescope has been redesigned for a second exoplanet search project called K2. NASA estimates the telescope has enough fuel to remain active into 2018.
By then, the space agency hopes to be ready to launch the Transiting Exoplanet Survey Satellite, which will search for small planets around the brightest stars in the sky, and the James Webb Space Telescope, which is designed to detect atmospheres on other planets. The results from Kepler, that new satellite and the Webb will inform the next generation of telescopes - ones that can actually take pictures of planets in motion around distant stars.
"It feels a bit like the end of an era," Thompson stated, "but actually I see it as a new beginning. It's amazing the things that Kepler has found. It has shown us these terrestrial worlds, and we still have all this work to do to really understand how common Earths are in the galaxy."