NASA finds 10 new near-Earth sized planets that could host life

Over 200 new planet candidates are part of a mission catalog recently released by NASA’s Kepler space telescope team. Of those, 10 are near-Earth size and orbiting in their star’s habitable zone. According to NASA, this means the exoplanets could have liquid water on their surface.

After gathering four years of data, the Kepler team put together the most comprehensive and detailed catalog of candidate exoplanets, planets outside our solar system. NASA says there are now 4,034 planet candidates identified by Kepler of which, 2,335 have been verified as exoplanets. Of roughly 50 near-Earth size habitable zone candidates detected by Kepler, more than 30 have been verified.

“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. Understanding their frequency in the galaxy will help inform the design of future NASA missions to directly image another Earth,” Mario Perez, Kepler program scientist in the Astrophysics Division of NASA’s Science Mission Directorate, said.

The Kepler data also suggest two distinct size groupings of small planets which have significant implications for the search for life. NASA says the final Kepler catalog will serve as the foundation for more study to determine the prevalence and demographics of planets in the galaxy, while the discovery of the two distinct planetary populations shows that about half the planets we know of in the galaxy either have no surface, or lie beneath a deep, crushing atmosphere – an environment unlikely to host life.

One research group took advantage of the Kepler data to make precise measurements of thousands of planets, revealing two distinct groups of small planets. The team found a clean division in the sizes of rocky, Earth-size planets and gaseous planets smaller than Neptune. Few planets were found between those groupings. It seems that nature commonly makes rocky planets up to about 75 percent bigger than Earth. For reasons scientists don’t yet understand, about half of those planets take on a small amount of hydrogen and helium that dramatically swells their size, allowing them to “jump the gap” and join the population closer to Neptune’s size.

Using the W. M. Keck Observatory in Hawaii, the group measured the sizes of 1,300 stars in the Kepler field of view to determine the radii of 2,000 Kepler planets with exquisite precision.

The Kepler space telescope hunts for planets by detecting the minuscule drop in a star’s brightness that occurs when a planet crosses in front of it, called a transit.

In February 2017, scientists announced that the TRAPPIST-1 system is home to seven Earth-size planets, three of which orbit in their star’s habitable zone.