Earth From Afar Would Look Only 82% Right For Life

Right now, we're staring hard at a small section of the sky, to see if we can detect any planets that may be habitable. The Kepler Spacecraft is focused on a tiny patch of sky in our Milky Way galaxy, hoping to detect planets as they transit in front of their stars. But if alien astronomers are doing the same, and detect Earth transiting in front of the Sun, how habitable would Earth appear? You might think, because, well, here we are, that the Earth would look 100% habitable from a distant loca...