The coolest exoplanets  Image credit:   You may not realize it
from reading the news, but so many extrasolar planets are being
discovered now that most aren't even reported. Sure, we all
heard about Gliese 581 C, the planet 120 trillion miles from
Earth which is the most "Earth-like" body yet discovered. But
since then the trickle of discoveries has turned into a flood,
and the news just can't keep up. So for those of you who don't
bury your heads in scientific periodicals, here are some of most
interesting new planets on the block:  "¢ Upsilon Andromeda b is
tidally locked to its sun like Earth is to its moon, which means
that one side is always facing the sun and the other away from
it. As such, it has such extreme surface temperature variations
that one side of it is like the deepest part of a volcano on
Earth, and the other side often below freezing.  "¢ TrES-3 is
about twice the size of Jupiter, 50 times closer to its sun than
Earth, and zips through its full orbit in only 31 hours, giving
it a 1.3-day y