Sturgeon's Law. There is a lot of bad Mathematics and Bad Physics in Science Fiction. pi is a true constant, not a physical variable, and curvature is another animal entirely, whose definition doesn't even include a factor of pi; it's defined entirely in terms of derivatives of the metric tensor, at least in the cases relevant to current Physics. Bafflegab is always easier than a correct explanation.
If you're a flatlander living on a sphere pi doesn't change, but formulae for, e.g., area, become more complicated. There was a similar phenomenon in the early days of network television, where scenes involving a computer would show a sorter. -- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Discussion List [[email protected]] on behalf of Bob Bridges [[email protected]] Sent: Friday, June 18, 2021 12:34 PM To: [email protected] Subject: Re: Coding for the future Completely OT, I'm reminded of Greg Bear's _Eon_, in which someone carried around a device for measuring the local value of pi. It's a way of detecting curvature in space, you see. You may think pi is 3.141519 everywhere, but if you're a Flatlander living on the surface of a sphere you'll have to get used to the fact that it can be anywhere between...let's see...between 0 and 4, I think. --- Bob Bridges, [email protected], cell 336 382-7313 /* I don't think I'd have been in such a hurry to reach adulthood if I'd known the whole thing was going to be ad-libbed. -Calvin's dad, Calvin & Hobbes 1989-05-11 */ -----Original Message----- From: IBM Mainframe Discussion List <[email protected]> On Behalf Of Seymour J Metz Sent: Thursday, June 17, 2021 14:01 It may be tongue in cheek, but while the value of pi will never change, the precision that you need may change, and changing a single precision 3.14159 to a more precise extended precision value is a lot easier if it's only in one place. Besides, while mathematical constants don't change, some physical constants, e.g., g, represent local conditions rather than laws of Physics. Take the length of the day - please! ________________________________________ From: Mark Jacobs [[email protected]] Sent: Thursday, June 17, 2021 11:49 AM The primary purpose of the DATA statement is to give names to constants; instead of referring to pi as 3.141592653589793 at every appearance, the variable PI can be given that value with a DATA statement and used instead of the longer form of the constant. This also simplifies modifying the program, should the value of pi change. ― FORTRAN manual for Xerox Computers ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
