The same process with comets could work for the moon, too. In fact, the moon might be the best place to terraform, seeing as it's so close. We'd have to find some way of steering about 100 comets the size of Halley's Comet toward our favorite satellite. Before the comets struck it, we'd have to find a way of blowing them up [sources: Benford; Cain].
Once we did, tiny ice shards would fly from the comets and scatter across the moon's surface, the beginnings of a rudimentary atmosphere. Eventually the comet strikes would force the moon to spin faster, and perhaps, just perhaps, nudge its axial tilt, which would create the seasons we enjoy on Earth. Scientists would then sprinkle algae and other organisms on the lunar surface, which would help to create oxygen. After a billion years or so, the Sea of Tranquility would really be a sea [sources: Benford; Cain].
Let's say we actually have the ability to terraform the moon or some other planetary body. Should we? Should humans tamper with alien environments? Should we just protect them? Some might argue for terraforming. It's in our best interest. Earth isn't going to last forever, and we might need another place to live. Others might say hold on to your molecules. Humans would just mess up a terraformed world, leaving it in worse shape than before [sources: Astrobiology Magazine, Philosophy Now].
Easy answers are elusive. So perhaps we should turn again to Ray Bradbury. He obviously thought about the implications of terraforming when he gave Driscoll a bag of seeds. At the end of the "Martian Chronicles," Earth has turned into a burned-out cinder because of a nuclear war, and a family is walking on Mars.
"I've always wanted to see a Martian," said Michael. "Where are they, Dad? You promised."
The father points into a canal.
"The Martians were there -- in the canal—reflected in the water. Timothy and Michael and Robert and Mom and Dad.
"The Martians stared back up at them for a long, long silent time ... "