NASA Discovers First Earth Sized Planet in a Habitable Zone

NASA announced today the discovery of the first Earth sized planet located within the habitable zone of another star. The planet, named Kepler 186F, is orbiting a red dwarf (M) type star approximately 500 light years from Earth.

Estimated to be only 10% larger than Earth, Kepler 186F is the outermost planet in a 5 planet system, living in a 130 day orbit in which it receives approximately one third of the solar heat as Earth does.  Still, it is considered enough to allow for photosynthesis, should life be present on the far away world.  That matter is anyone’s guess, as the discovery team noted that it is notoriously difficult to determine the age of red dwarf systems, because the stars tend to be more stable than larger stars which go through a number of telling changes in their lives.

Because it orbits a red dwarf, Kepler 186 is described as more like Earth’s cousin than Earth”s sister, a comparison which is not likely to be further validated for some time due to the distance between the two. Still, what is particularly significant about this announcement is the commonplace nature of red dwarf stars. Although you cannot see them at night with the naked eye, they comprise approximately 70% of all known stars in the galaxy, including many in our local neighborhood. Though yet to be proven, the existence of Kepler 186F suggests that the Milky Way could be full of similar Earth sized planets, with many inside habitable zones, areas where surface water could exist.

Kepler is not capable of detecting the nature of comparatively small planets such as this one, meaning much will remain unknown, whether it is mostly iron, rocky or icy, or even if it has an atmosphere.

Soon however, that will begin to change, and our perception of the nature of the universe could be in for a major alteration.   A new spacecraft, the TESS observatory, is scheduled to be launched in 2017, and it will scan the local area, including red dwarfs, for more such systems. Those which are confirmed to have Earth sized planets will become early targets for the spacecraft which the space science community has seen all its treasure spent, the James Webb Space Telescope, scheduled for launch in 2018.  Labeled the next great observatory, the $8.8 billion mega project is expected to be able to determine much more about exo-planets than any other instrument yet built or launched,  including the presence of water vapor in the atmosphere, and just possibly, tell tale signatures of life.