See here.
The Kraoka could not and did not settle on planets with suns as cool as Sol.
Antoran has six planets with liquid water.
The outermost colonized planet, Neuheim, is too cold for the Kraoka but suitable for human beings.
Its brilliant auroras even in temperate zones entail an energetic giant star.
Neuheim must be very far out because the sun is not seen as a disc, because there are no solar tides and because the year is very long.
The year must be very long because human beings settled there forty standard years ago and have recently moved poleward as the lower latitudes became too hot.
Despite its enormous distance from the sun, Neuheim is humanly habitable and its inhabitants even have a deep suntan.
Only a blue giant star meets these criteria. Beta Centauri is the only nearby blue giant. Giants do not form planets so Beta Centauri must have captured a rogue system, which explains the eccentric orbits.
Q.E.D.
5 comments:
Kaor, Paul!
I see now I really should reread "A Sun Invisible."
Sean
Tho' current evidence indicates planets may form around blue giants. Certainly some have 'dusty' accretion disks around them.
Dear Mr. Stirling,
That is interesting, that some blue giants might "natually" have their own planets.
Sean
Back in Poul's day he used the best available science -- but we were working out theories of planetary formation from a sample of exactly 1.
Since we've been able to observe extrasolar planets, we've found they're much, much more common than previously believed. Most stars have planets, and their size and arrangement is very unlike our solar system.
Dear Mr. Stirling,
I agree, Poul Anderson wrote his stories using the best AVAILABLE scientific knowledge, and reasonable extrapolations from that information, he had access to.
And PA was not one of those persons who formerly thought extra-Solar planets were rare. And it's my hope that planets with oxy/nitrogen atmospheres similar to ours are soon found.
Sean
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