After careful observations of images taken by the Kepler Space Telescope, astronomers announced the discovery an Earth-type planet called Kepler-186f. It orbits within its sun’s habitable zone. Planets in such an area where it is not too hot or too cold give them a better chance of containing liquid water and a livable atmosphere.
The exact mass of Kepler-186f is believed to be 10 percent larger than Earth and 490 light-years away. The Earth-sized planet is located in the constellation of Cygnus. One year on Kepler-186f lasts 130 days. Its orbit is nearly the same distance as Mercury. Despite the close proximity, the red M-dwarf sun is cooler and dimmer. The newly found planet receives only a third of the energy Earth’s sun delivers making for much more redder skies.
Finding the planet involved the Kepler Space Telescope staring at 150,000 stars and waiting for starlight dips. When such a phenomenon occurs, astronomers can begin confirming the general size and location of a distant planet. Kepler-186f’s 130 day orbit made it easier to track.
Of the planets discovered outside Earth’s solar system, less than two dozen orbit their sun’s habitable zone. Too close of an orbit causes water to boil off into space. Too far away leaves the planet locked in a frozen wasteland. Images taken by the Kepler Space Telescope of an Earth-type planet such as Kepler-186f make it a worthy candidate for further astronomical studies.
The size of a planet matters. If a planet is 50 percent larger than Earth, it contains more gravity. The increased gravity could attract a hydrogen-helium. Such conditions cause the planet to be enshrouded with a gassy atmosphere making it too unsuitable for long-term exploration.
Jason Rowe, an astronomer with the SETI Institute in Mountain View, CA believes the discovery of Kepler-186f is the first of more to come. Although the team from the Kepler Space Telescope needs more time to analyze the data, they were the first to confirm the new planet’s existence.
UC Berkeley astronomer Geoffrey Marcy called the discovery historic. It is the first and best case scenario of an Earth-type planet found within a habitable zone.
Doug Hudgins, a NASA program scientist for the Kepler Space Telescope, considered the new planet a milestone. Finding Earth-sized planets are rare, one with water and habitable atmosphere are even rarer.
Future NASA missions include the scheduled 2018 launch of the James Webb Space Telescope. The satellite will be equipped with infrared-sensitive capabilities making it easier to isolate water signatures and molecules. One of its first points of observation will most likely be Kepler-186f.
There are astronomers who contend that M-dwarf stars are too volatile for life on nearby planets. Their suns emit more solar flares. The damaging radiation could easily reach the planets and severely damage their atmospheres. Kepler-186f appears to orbit close to the outer edge of its habitable zone. It may contain more ice extending from its polar regions.
Dimitar Sasselov of the Harvard-Smithsonian Center for Astrophysics, noted that people are about to learn if life in the universe is a rare phenomenon or common place. Astronomers will soon have a chance of answering that question.
Sara Seager, an MIT astrophysicist believes planets are diverse. A whole range of them could orbit within their sun’s habitable zone. Since M-dwarf stars make up 70 percent of the Milky Way Galaxy, there is the potential of finding Earth-type planets teaming with life.
Once humans develop interstellar travel, knowing which part of the galaxy to explore for habitable planets would be helpful. The announcement by astronomers of an Earth-type planet discovered by images taken by the Kepler Space Telescope could make a planet Kepler-186f one of the first places interplanetary star ships visit.
By Brian T. Yates