The search for planets around other stars has spawned new observing methods, and there have also come a few new terms. First of all, a planet circling another star is an exoplanet, meaning it's a planet in some other solar system. Based on what we know of life on our planet, it's assumed that for life to exist elsewhere, it would probably need water and relatively temperate conditions. Astronomers believe that the requirement for life on Earth is that our planet has to reside somewhere in the range of .95 to 1.15 astronomical units from the Sun. (An astronomical unit is the mean distance between the Sun and the Earth.) This is known as the Habitable Zone. However, astronomers also refer to it by a more colorful name -- the Goldilocks Zone. But because stars brighten and swell as they age, their habitable zones gradually move outward. Thus the term Continuously Habitable Zone has been coined to take into account the length of time that a planet remains in a habitable zone. If the period a planet spends in a habitable zone is relatively short, then it's believed any life there would not have had sufficient time to evolve beyond a rudimentary stage. So far, all the planets discovered around other stars seem to be very large -- huge gas giants like Jupiter. However, at least a couple of these giants could be in their stars' habitable zones, and it's speculated that they may have moons on which life could live happily ever after. …Like Goldilocks.