Discovery of Kepler-452b
The news media is currently full of the news of the discovery of Kepler-452b, the planet that is supposed to be Earth’s twin.1,2 It was discovered using the satellite-borne telescope, Kepler, where the exoplanet was found to be at a distance of about 1400 light-years. It has a mass about five times that of Earth and diameter about 60% larger, hence a gravity nearly double that of Earth. It has a year3 about 20 days longer than Earth. That makes it the most similar planet to Earth yet and it is located in the habitable zone around its parent star, which is a G-class star, the same class as our sun.
You see pictures (e.g. Figure 1 here) of a planet with oceans and land masses and some even with green vegetation drawn in. But none of these are actual images of the planet. It is too far away for such a thing, even with man’s best telescopes.
Why all the hype? Well, it is the hope of life being found elsewhere. The way it goes is: find an Earth-sized planet in the habitable zone, called the Goldilocks zone—not too hot, not too cold, but just right—the distance from the parent star where water is in its liquid form—detect the presence of water in its atmosphere and that gives you a good chance of finding life.4