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.)I hadn't thought of it like that. That's a very suggestive idea. I might write fiction about this.
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.
‘Could a rule be given from without, poetry would cease to be poetry, and sink into a mechanical art. It would be μóρφωσις, not ποίησις. The rules of the IMAGINATION are themselves the very powers of growth and production. The words to which they are reducible, present only the outlines and external appearance of the fruit. A deceptive counterfeit of the superficial form and colours may be elaborated; but the marble peach feels cold and heavy, and children only put it to their mouths.’ [Coleridge, Biographia ch. 18]
‘ποίησις’ (poiēsis) means ‘a making, a creation, a production’ and is used of poetry in Aristotle and Plato. ‘μóρφωσις’ (morphōsis) in essence means the same thing: ‘a shaping, a bringing into shape.’ But Coleridge has in mind the New Testament use of the word as ‘semblance’ or ‘outward appearance’, which the KJV translates as ‘form’: ‘An instructor of the foolish, a teacher of babes, which hast the form [μóρφωσις] of knowledge and of the truth in the law’ [Romans 2:20]; ‘Having a form [μóρφωσις] of godliness, but denying the power thereof: from such turn away’ [2 Timothy 3:5]. I trust that's clear.
There is much more on Coleridge at my other, Coleridgean blog.
Tuesday, 14 May 2013
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':