Gazing Afar for Other Earths, and Other Beings

The stars are being monitored by a $600 million satellite observatory named Kepler, whose job is to conduct a kind of Gallup poll of worlds in the cosmos.

Its gaze is fixed on a patch of sky about 20 full moons across near the Northern Cross, in the constellations Cygnus and Lyra, containing about 4.5 million stars.

Over the next two or three years, as Kepler continues to stare and sift, astronomers say, it will be able to detect planets in the “Goldilocks” zones, where it is neither too hot nor too cold for liquid water.

Last year, a team of American astronomers announced that they had discovered a Goldilocks planet orbiting a dim red dwarf star at just the right distance to harbor water on its surface, making it a potential site for life.

Traditional religious images of ourselves as God’s creatures, or even of God, could be in for a rough time if we ever discover pond scum living by completely alien chemical rules on some moon or planet, let alone the Borg — the alien race ruled by a collective mind on “Star Trek” — inhabiting some distant realm.

Another is a planet composed almost entirely of superheated water and sometimes called the Steam World; it is known as Gliese 1214b, about 40 light-years from here in the constellation Ophiuchus.

A planet gives its star a little gravitational tug as it goes around, causing the star to go back and forth, or wobble, a little as both star and planet circle the same center of gravity.