Undreamed Shores - Ocean Worlds: The Story of Seas on Earth and Other Planets - page 260

Kepler-62e and -62f might, just might, represent such planets. Their
distance from us—1,200 light years—makes it hard to say. But they
are roughly Earth-sized, and broadly within the habitable zone where
liquid water could exist (although in the case of Kepler-62f, the more
distant of the two from its sun, a thick heat-trapping blanket would be
necessary). Both planets are big enough to retain such an atmosphere
though, and the potential similarities with Earth have already trig-
gered speculation of swimming life, and flying life, and potentially
intelligent life. 174
Is this completely untestable speculation? Maybe not completely.
Attempts to model how such worlds might evolve suggests that if
these are water worlds, then there is a good chance that they are
complete water worlds—with sufficient ocean to completely cover
the planet's surface. Our own planet might have become like this,
after all, with just a slight change in its original recipe (some say more
large comets hitting it when our solar system was young). In a total
ocean world, marine life might evolve, and maybe even intelligent
life—but perhaps not intelligent, manipulative, resource-extracting,
and technological life. Think of the whales and dolphins on Earth:
intelligent, with sophisticated communication, but without the means
to become farmers, engineers, or rocket scientists. 175 Water-covered
worlds may well outnumber those Earth-style ones in which there is
a nice balance between land and water. Kepler-22b, for instance, was
the first planet detected that sits in the habitable zone around its yel-
low star (see Plate 9). It has a radius more than twice that of Earth but
seems less dense, so it might be mainly ocean with a rocky core. Thus,
quite extraordinarily deep waters may lie there, quite unlike Earth's
oceans, although that has not stopped speculation concerning the
possibility of life.
The sum effect of COROT and (especially) Kepler has been to revo-
lutionize our understanding of planets in the cosmos. There are lots