All of these worlds were found in a patch of sky near the Cygnus constellation in our Milky Way galaxy.
The James Webb Space Telescope, however, is capable of observing large exoplanets and detecting starlight filtered through their atmosphere, which will enable scientists to determine the atmospheric composition of the planets and analyze them for the presence of gases that can create a biological ecosystem. The timing of each dimming tells you how long a year is on that planet.
NASA announced the latest findings in its hunt for friendly exoplanets on Monday, and the haul includes 219 new candidates. Today's announcement whittled those candidates down to 4,034. Of those, 2,335 are verified exoplanets.
In February, NASA's Spitzer Space Telescope revealed the TRAPPIST-1 system, which features seven Earth-size planets orbiting a single star - three are in the habitable zone. That brings the final count of near-Earth candidates to about 50.
KOI-7711, an unconfirmed exoplanet at this time, appears to be our best candidate for an Earth-like alien world.
The potential discoveries are part of the final catalog of results being released from the first Kepler space telescope mission.
"The Kepler data set is unique, as it is the only one containing a population of these near Earth-analogs - planets with roughly the same size and orbit as Earth", Dr. Mario Perez, a scientist on NASA's Kepler program, said in the press statement. Understanding how frequent planets like our own will help NASA develop the next telescope that will directly image planets like Earth. Scientists went back through all the data Kepler gathered during its first four years to make sure they didn't miss anything.
Before Kepler, astronomers only knew of giant Jupiter-sized exoplanets, some in astonishingly tight orbits around their stars. Looks like a transit. It has an orbital period much similar to Earth's at 303 days.
With the release of this catalog, derived from data publicly available on the NASA Exoplanet Archive, there are now 4,034 planet candidates identified by Kepler. Scientists can't just observe one transit and say it's a planet.
Plus, what Kepler sees is just the tip of the iceberg. Kepler is basically viewing tiny solar eclipses. NASA is planning a manned mission to planet Mars in near future. 10 exoplanets among the latest list are in the "Goldilocks" zone and their size is comparable to that of our planet Earth. With the launch of our Transiting Exoplanet Survey Satellite (TESS) and the James Webb Space Telescope (JWST) in 2018, we're going to search for planets nearest the sun and measure the composition of their atmospheres.
Kepler performs its mission by gathering extremely stable observations of distant stars, and watches for when the light from those stars dims, due to a solid object (most likely a planet) passing between the telescope and that star.