In the four years since its launch, Kepler has chalked up 122 new and confirmed planets. It's also caught the scent of nearly three thousand additional objects, of which probably 80 percent or more will turn out to be other-worldly orbs.

The math is dead simple: it seems that the frequency of planets able to support life is roughly one percent. In other words, a billion or more such worlds exist in our galaxy alone. That's a lot of acreage, and it takes industrial-strength credulity to believe it's all bleakly barren.

Diminutive worlds are more likely to be rocky, and lapped by oceans and atmospheres. In the vernacular of 'Star Trek,' these would be M-class planets: life-friendly oases where biology could begin and bumpy-faced Klingons might exist.

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