BKPHZDBT.RVW 940523 "Phaze Doubt", Anthony, 1990, 0-441-66263-3, U$5.95 %A Piers Anthony %C 200 Madison Avenue, New York, NY 10016 %D 1990 %G 0-441-66263-3 %I Ace Books/The Berkley Publishing Group %O U$5.95 %S Phaze/Proton %T "Phaze Doubt" The Phaze/Proton series is a combination of fantasy and science fiction, so Anthony doesn't have to be accountable for much. In this, the last (oh, please!) of the series, though, he falls prey to "fiction series disease": the overwhelming urge to explain mistakes you made earlier. Proton/Phaze has been portrayed as having the south pole pointed towards the sun, and yet has light overhead everywhere. This, explains Anthony, is because Phaze/Proton is a hollow shell surrounding a black hole. The black hole, as everyone knows, sucks light into itself so that light falls straight down onto the surface of the planet. In fact, because of some other diddling earlier in the series, Proton/Phaze is a half-sphere. Presumably this means the half shell is in orbit around the black hole. Black holes do not "suck" light. (At least they don't in our universe and this is where the book is set. No magical help, this time.) A black hole is a gravitational field which is so intense that the orbital velocity; the speed an object must travel in order to stay in orbit; meets or exceeds the speed of light. This means that light which is close enough to a black hole will not be able to escape: it cannot go faster than the speed necessary to maintain an orbit. However, gravitational intensity decreases, the further you are from the source of the field. Therefore, light further away from the black hole, while it may be bent by the gravity sink, will not be "pulled in". Let us consider the gravitational strength of a black hole. The space shuttle flies in a fairly low orbit, low enough that we can, for purposes of calculation, say that it orbits at the level of the earth's surface. The shuttle flies about 40,000 times slower than the speed of light. Therefore, if the earth were to become a black hole, the gravity would be strong enough to smear everyone into a paste. A black hole can be made arbitrarily small, and therefore it is possible to postulate a black hole which, at a planetary distance, generated a gravity of only one G force. However, (1) such a black hole would be vanishingly (you should pardon the expression) small; and, (2) a one G force wouldn't have much impact on light. Ah, but what if the Phaze/Proton-on-the-half-shell is in orbit about the black hole? Well, leaving aside the difficulty of landing on such an object, there are three problems. The first is that such an arrangement would have almost no stability in terms of staying right side out. The second is that, although you could make the orbit arbitrarily fast in order to counter an arbitrarily strong gravity, you would be subject to tidal forces because of varying distances from the centre of the orbit. At the very least, people on mountain tops would weigh less than those in the valleys. At the worst, the most likely case when you are talking about gravity strong enough to bend light, Proton/Phaze residents would have feet weighing several tons while their heads were attempting to fly into space. (Anything lifted above the head would likely make it.) The third problem relates to the poles. I know that Anthony postulates four, but I am talking about the real two on the spin axis. These would have no centrifugal boost, and gravity would therefore be correspondingly stronger. However, the problems of characters being immobilized by weight at the poles would not last long: the poles, themselves, would tend to collapse inward. The problem of running a mining operation on a thin-shelled planet is left as an exercise to the reader. copyright Robert M. Slade, 1994 BKPHZDBT.RVW 940523 ====================== DECUS Canada Communications, Desktop, Education and Security group newsletters Editor and/or reviewer ROBERTS@decus.ca, RSlade@sfu.ca, Rob Slade at 1:153/733 Author "Robert Slade's Guide to Computer Viruses" (Oct. '94) Springer-Verlag