Interstellar travel

Out of a long, ill-tempered, repetitive and mostly nothing-new-here comments thread to a Crooked Timber John Quiggin article on interstellar travel, I found this one, very intriguing (story-making intriguing) observation by 'Patrick':

The time for the sun to orbit the galactic center is about 250 million years.(galactic year, 18 having elapsed since the earth was formed.) That is a long time, but we’re also traveling an extraordinary distance. During that time, the earth is oscillating up and down out of the galactic ecliptic. (Like a buoy in the ocean, bouncing up and down.)

What this means is, although there are no stars that we can easily reach now. Many,many stars will venture quite close to us on the scale of a galactic year.(and in far less time.)

If habitable planets are not too rare, our best bet is to wait for one to come to us, then send people across when our stars are closest. This is not too different from how orbital windows work when sending spacecraft to Mars: Reaching habitable planets is expensive now, but it will not always be so, even if we do not develop any amazing new technologies.

To put it in perspective. The earth has gone about 90 degrees around the galactic center since dinosaurs went extinct. In that time numerous stars will have passed within a light year of earth. Some of them probably had habitable planets.

I hadn't thought of it like that. That's a very suggestive idea. I might write fiction about this.