Astronomers have discovered a distant planet that appears to have an atmosphere similar to Earth, the possibility of water at its surface and the theoretical potential to support life. It is the first validated planet found in the “habitable zone,” defined by the distance from a star that might allow for the existence of liquid water. The planet is orbiting Kepler-186, a dwarf star that’s cooler than Earth’s sun and burns hydrogen, according to a report in the journal Science. Life is most likely to arise on planets with liquid water.
“The host star, Kepler 186, is an M1-type dwarf star which means it will burn hydrogen forever,” said Justin Crepp, as astrophysicist from the University of Notre Dame who worked on the mission. “There is ample opportunity to develop life around this particular star and because it has just the right orbital period, water may exist in a liquid phase.” The planet in the habitable zone is about 400 million miles from its host star, roughly the distance of Jupiter from the sun in our solar system. Kepler-186f orbits its star once every 130 days and receives one-third the energy that Earth does from the Sun, placing it near the outer edge of the habitable zone. If you could stand on the surface of Kepler-186f, the brightness of its star at high noon would appear as bright as our Sun is about an hour before sunset on Earth. The other four planets are closer to their host star and are exceedingly hot, according to the astronomers. The planet was found using the Kepler Space Telescope.
The five planet system is about 500 light-years from Earth and is found in the constellation Cygnus. If we took our fastest space probes, the Helios Probes, as a space vehicle travelling at 150,000 mph, it will take us 4,473 years to travel one light-year. So to reach Kepler 186 will take us 2,236,500 years! We have a long way to go in speeding up space travel.