Earth is the lone oceanic planet in the family of the Sun. Now imagine a planetary system with two of them. Astronomers may have found just such a system. And the two water-worlds orbiting there are among the closest analogs of Earth yet found. The star Kepler 62, about 1200-odd light years away in the constellation Lyra, is like our Sun but smaller and cooler. So the habitable orbits – where water can be liquid – are closer in. Each of the two candidate water-worlds could be entirely covered by a global ocean, according to astronomers’ computer models. Orbiting once every 122 Earth-days, Kepler 62e could be tropical – humid and hot – with a very cloudy atmosphere. It’s perhaps 60% bigger than Earth. Further out – in a 267-day orbit – Kepler 62f is about 40% larger than Earth. And it’s almost surely cooler; in fact, it could be an ice-ball from pole to pole unless it has a lot of carbon dioxide in its atmosphere. These two share their star with three less hospitable planets, orbiting too close-in; and so too hot for liquid water. With no land-masses and no chance for fire, it’s hard for us to visualize how any intelligent inhabitants could build a technological society on a totally oceanic world. But imagine for a moment growing up on a planet from which you could see the lights of cities on another. Surely that would give you a good reason to build spaceships… For SPACE.com, I’m Dave Brody