Several years ago, astronomers discovered that a distant sun was surrounded by a halo of water vapor. Now they know how it was created. If we can make water in space, we've surmounted one barrier to space colonization.
According to CNN:
The water vapor sits in a dusty cloud surrounding IRC+10216. Scientists deduced that ultraviolet light from surrounding stars had penetrated that dusty cloud, breaking up molecules in it like carbon monoxide and silicon monoxide, which in turn released oxygen atoms.
Those oxygen atoms attached themselves to hydrogen molecules, forming water.
"The ultraviolet light didn't create it — it helped it to be formed," [astronomer Goran] Pilbratt told CNN.
Ultraviolet light is the only way water could have been produced in such conditions, he said.
The star in the middle of this vapor is a so-called "carbon star," a dim red giant, and now scientists are scanning the skies for similar stars in the hope that they may be producing water too.
Do water-consuming interstellar civilizations use these stars as water farms? Can they be created artificially by beaming UV into nebulae and other regions of stellar dust? The whole thing sounds like the setup to a great space opera about the galactic water wars.