WMARTIN@OFFICE-8@sri-unix (10/29/82)
From: WMartin at Office-8 (Will Martin) In reference to the discussion of Sagan's formula, I just heard an NPR Journal item (National Public Radio, aired locally on 28 Oct 82) which was an interview with James Michener regarding his new book, "Space". In this interview, he talked about the same sort of formula that was printed here. Of course, since this was radio, there was no detail, but a couple of the comments were: 1. Binary and multiple star systems are excluded, as they are unlikely to have habitable planets. (I can see logic in this; planets in such systems are likely to be gobbled up by one of the stars, or be in eccentric orbits which cause wide variations in heat, or just receive too much radiation from all those suns.) That would make "Fp" much less than "~1". 2. End result was 15 current intelligent civilizations per galaxy. I don't have any particular emotional attachment to this result, I'm just reporting it as it is appropriate to the current discussion. It loks like Michener's "Space" might be worth reading... Will
CSvax:Physics:els (11/02/82)
Logic doesn't quite provide the right answer. Binaries in which either,
1: the primary and secondary are far apart (Alpha Cent., for example) ,or
2: the primary and secondary are very close (grazing, or nearly so), have
appriciable regions where there could be stable planetary orbits.
els[Eric Strobel]
pur-ee!pur-phy!els