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Groups > alt.checkmate > #55163
| From | "Checkmate, DoW #1" <Lunatic.Fringe@The.Edge> |
|---|---|
| Newsgroups | alt.checkmate, alt.free.newsservers, alt.usenet.kooks, sci.physics |
| Subject | Re: Questions ko0ky runs away from really fast |
| Date | 2016-02-04 21:30 -0800 |
| Organization | Altopia Corp. - Usenet Access - www.altopia.com |
| Message-ID | <MPG.311dd33911424b2f98c528@news.altopia.com> (permalink) |
| References | <n8ut8l$v4p$1@gioia.aioe.org> <5bda0cadc6d53a77d20e468705959858@dizum.com> <n919ml$ps1$1@gioia.aioe.org> |
Cross-posted to 4 groups.
In article <n919ml$ps1$1@gioia.aioe.org>, kkensington01@gmail.invalid says... > > On 04/02/2016 12:16 PM, Friendly Neighborhood Vote Wrangler Emeritus wrote: > >> 1. On a winter's night, with snow on the ground, is it typically colder > >> or warmer when there is cloud cover versus when it is clear? > > > > clouds over water, snow or ice will have negligible effect on temperature. > > BZZZT! > > http://littleshop.physics.colostate.edu/activities/atmos1/ColderOnClearThanCloudy.pdf > > You bit my shiny hook at last, ko0ky, and thus exposed your l0on climate > change denial, and yourself, as intellectually bankrupt. > > Final victory on the climate change question goes to kensi. > > Thank you for playing, goodbye. > > >> 2. What might NASA have meant by "an active Sun" *other* than sunspot > >> activity? > > > > There's no mention of "sunspot activity" in the *three* referenced > > Non-answer. What I said was mentioned word-for-word was "an active Sun". > You have k'lamed that they meant something different from "sunspot > activity" by this. You have been asked to state exactly what. > > Our ruling on question #2 is that you answered with (approximately 200 > screedy lines of) *crickets*. > > Thus, Question 2 remains unanswered. > > > And you call yourself an astrophysicist? Pshaw, you're not even smart > > enough to be an astrologer. > > To get angles summing to other than 180 degrees the triangle has to be > in a curved manifold. The angle sum will be less the more negative the > curvature's manifold, and greater the more positive, being 180 when the > manifold is flat. A good example: take the meridians at 0 degrees and 90 > degrees longitude on Earth, and take the segments of these meridians > from north pole to equator. Add in the arc of the equator joining these > endpoints by the shortest distance. This is a triangle in Earth's > surface as a curved manifold, as the sides are segments of great > circles, which are geodesics of that manifold. The interior angles are > all 90 degrees, so the angle sum is 270 degrees. > > From this can be intuited that the relative scale of the triangle and > the (possibly negative) radius of curvature of the manifold determines > the angle excess/deficit, as making the sphere and triangle smaller by > the same factor preserves the angle sum of 270. (Earth is actually > (approximately) an oblate spheroid, which doesn't alter the angles, > though it makes the triangle a not-quite-equilateral isosceles > triangle.) Make only the triangle smaller and the angle excess shrinks > toward zero, the angle sum tending to 180, and ditto making only the > sphere bigger. The exact quantitative relationship is given by the > Gauss-Bonnet theorem, which states: > > integral_M K dA + integral_dM k_g ds = 2*pi*chi(M) > > where M is the portion of the manifold enclosed by the triangle (or, > actually, any figure) and dA differential units of the enclosed area, K > is the Gaussian curvature over M, dM is the triangle itself (or other > figure), k_g is the geodesic curvature of this boundary, ds is the > differential on the perimeter (so integral_M dA = area A and integral_dM > ds = perimeter s), and chi(M) is the Euler characteristic of M (1 for a > simply-connected, bounded area with no holes such as our triangle). For > a piecewise-geodesic boundary like our triangle, integral_dm k_g ds is > the sum of the angles by which the geodesic segments turn at the corners > of the boundary, which is pi minus the interior angles. So for the > triangle, it's 3*pi minus the sum of the interior angles whose sum with > integral_M K dA equals 2*pi*chi(M) = 2*pi, i.e. 3*pi - angle_sum + > curvature_integral = 2*pi, or angle_sum - pi = curvature_integral -- the > deviation of the angle sum from 180 degrees (but expressed in radians) > equals the integral of the curvature of the manifold over the portion > enclosed by the triangle. For a manifold of constant curvature (e.g. a > sphere) that integral equals the triangle's area times the constant > curvature (so, the angle deviation grows as the triangle's area grows, > and as the curvature grows); the curvature in question is 1/r^2 where r > is the radius of curvature (for a sphere, this is the radius of the > sphere; for a manifold of constant negative curvature, it's actually > imaginary and of smaller magnitude as the curvature becomes stronger). > > The importance of the foregoing to an astrophysicist is, of course, > general relativity. Space itself (and indeed, space-time) is a curved > manifold, and in fact this phenomenon affects not only "plane" figures > but solids, and thus spherical angles, in curved space(-time). For > instance, a tetrahedron's four interior solid angles' sum will change > near, say, a black hole or other dense object. (There's no nice tidy > constant in steradians here analogous to angle sum = pi radians for a > plane triangle; the sum of the solid angles of a tetrahedron depends on > the six dihedral angles of the tetrahedron, being twice their sum minus > 4*pi. For the regular, Platonic solid tetrahedron with > equilaterial-triangle faces, in Euclidean space, it's 6*cos^-1(1/3) - > 4*pi, and will exceed this in positively-curved space and be deficient > of it in negatively-curved space.) > > > <sn<SMACKAK00K!> > > Since you have now been thoroughly and utterly *destroyed* on every one > of your kOoky contentions, our ruling is: Snicker denied. > > *snicker* Well done, Paul! You get to join the "I Kicked Fakey's Ass On Usenet" club. Free 'shrooms for everyone! <snicker> -- Checkmate, AUK DoW #1 AUK Hammer of Thor award, Feb. 2012 (Pre-Burnore) Destroyer of the AUK Ko0k Vote (Post-Burnore) Originator of the "Dance for me" (tm) lame Copyright © 2016 all rights reserved
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Re: Questions ko0ky runs away from really fast "Checkmate, DoW #1" <Lunatic.Fringe@The.Edge> - 2016-02-04 21:30 -0800
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