The Sun is getting warmer, and on a geological scale it has dire consequences for life on Earth.
M Class
In the Star Trek fictional universe, habitable Earth-like planets are designated as Class M planets, where M stands for the Vulcan word Minshara. In the real universe such planets would also be known as class M, but for different reasons.
The Red Zone
Recently there’s been news of the discovery of the closest potentially habitable exoplanet yet. Named Gliese 832 c, it is a “super-Earth” orbiting in the habitable zone of a red dwarf star. In April of this year, there was news of the “most Earth-like planet yet”. Named Kepler 186 f, it is a super-Earth orbiting a red dwarf star. In 2012, there was an announcement of the “most habitable exoplanet yet” named Gliese 581 g. It is a …wait for it… super-Earth orbiting a red dwarf. Whenever a new potentially habitable world is announced, it will likely be a super-Earth orbiting a red dwarf. But why?
Twins
NASA and JPL have announced the discovery of an Earth-sized planet orbiting in the habitable zone of its star. The planet is named Kepler-186f, and is the 5th planet from its star, Kepler 186.
Goldilocks Zone
Earth is the one planet we know of that is well suited for life. Of course this is a sample size of only one, and it’s a biased sample, since we’re it. This means we should take any speculation on the existence of life on other planets with a grain of salt, but there are some things we can at least tentatively speculate on.