Question on infinity (singularity)
in [Math]
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From: MicroTech on 15 Mar 2010 03:34 In physics (and cosmology) I quite often see references to "singularities" (as inside "black holes" and as the origin of the so called "big bang") as being "points with no size, of infinite mass, infinite density, infinite temperature, and infinite pressure" (or something to this effect). As I understand an "infinite quantity", it will stay infinite even if one adds n, or subtracts n, or multiplies by n, or divides it by n <> 0... I am told by science that "the universe is estimated to contain 10^80 particles." This is a big number, for sure, but a far cry from an infinite number of particles. It seems to me that if we subtract 10^80 from an infinity of particles, the remaining number of particles would still be infinite... So, if the "original singularity" indeed had infinite mass, what in the "big bang" made it finite, suddenly? And does not the same question equally apply to density, temperature, and pressure? A related question is, if something has infinite density, how can there be room for its constituent particles to freely move around (as in temperature)? How can something with infinite density be infinitely hot? Another related question is: if a "singularity" shows up in an equation (as is claimed to happen in some of Einstein's equations), is this not a sure sign that something in the equation is wrong? Like dividing by zero, somewhere? As I am neither a mathematician nor a physicist, it may well be that I've got the concept of "infinity" wrong. I would really appreciate it if someone in this forum can point out to me where my understanding is wrong (and provide correct interpretations of the term)! References to published papers (accessible on line), especially papers showing what the "Einstein Singularities" are, would be very much appreciated! Henry Norman
From: David C. Ullrich on 15 Mar 2010 06:00 On Mon, 15 Mar 2010 00:34:15 -0700 (PDT), MicroTech <henry.ko.norman(a)gmail.com> wrote: >In physics (and cosmology) I quite often see references to >"singularities" (as inside "black holes" and as the origin of the so >called "big bang") as being "points with no size, of infinite mass, >infinite density, infinite temperature, and infinite pressure" (or >something to this effect). Are you sure you've seen a description that includes infinite _mass_? I tend to doubt it. >As I understand an "infinite quantity", it will stay infinite even if >one adds n, or subtracts n, or multiplies by n, or divides it by n <> >0... > >I am told by science that "the universe is estimated to contain 10^80 >particles." This is a big number, for sure, but a far cry from an >infinite number of particles. It seems to me that if we subtract 10^80 >from an infinity of particles, the remaining number of particles would >still be infinite... So, if the "original singularity" indeed had >infinite mass, what in the "big bang" made it finite, suddenly? I don't believe that the big bang is supposed to involve infinite mass, in the standard story. > And >does not the same question equally apply to density, temperature, and >pressure? The same does not apply. There's such a thing as conservration of mass (or rather mass and energy). There's no law of conservation of pressure or temperature or density. First, I'm pretty sure that nobody would say that they're certain that those supposed singularities have or had actual physical existence - could just as well be that the theory that seems to lead to singularities simply breaks down and reality involves tamer things with huge but finite temperature, pressure and density. In fact my impression is that most would say that that's likely, on quantum-mechanical grounds. But in any case, if you take a given mass and compress it into zero volme (_if_ that's actually what happened) then it has infinite density. "How can that be"? Could be that that never actually happened. If it _did_ happen, the answer to "how could that be" is just that physics involves very strange things that are nothing like your everyday experience - things are the way they are, whether or not the way they are makes sense. >A related question is, if something has infinite density, how can >there be room for its constituent particles to freely move around (as >in temperature)? How can something with infinite density be infinitely >hot? > >Another related question is: if a "singularity" shows up in an >equation (as is claimed to happen in some of Einstein's equations), is >this not a sure sign that something in the equation is wrong? Like >dividing by zero, somewhere? > >As I am neither a mathematician nor a physicist, it may well be that >I've got the concept of "infinity" wrong. I would really appreciate it >if someone in this forum can point out to me where my understanding is >wrong (and provide correct interpretations of the term)! > >References to published papers (accessible on line), especially papers >showing what the "Einstein Singularities" are, would be very much >appreciated! > >Henry Norman
From: William Elliot on 15 Mar 2010 06:12 On Mon, 15 Mar 2010, MicroTech wrote: > In physics (and cosmology) I quite often see references to > "singularities" (as inside "black holes" and as the origin of the so > called "big bang") as being "points with no size, of infinite mass, > infinite density, infinite temperature, and infinite pressure" (or > something to this effect). > Don't take them seriously; it's just allegory for what they don't understand. > As I understand an "infinite quantity", it will stay infinite even if > one adds n, or subtracts n, or multiplies by n, or divides it by n <> > 0... > No. If n < 0, then n * oo = -oo. > I am told by science that "the universe is estimated to contain 10^80 > particles." This is a big number, for sure, but a far cry from an > infinite number of particles. It seems to me that if we subtract 10^80 > from an infinity of particles, the remaining number of particles would > still be infinite... So, if the "original singularity" indeed had > infinite mass, what in the "big bang" made it finite, suddenly? And > does not the same question equally apply to density, temperature, and > pressure? It's all nonsense; just an extreme extrapolation of 1/x as x -> 0+. > A related question is, if something has infinite density, how can > there be room for its constituent particles to freely move around (as > in temperature)? Nonsense. Something with infinite density and non-zero volume would either drop out of the universe or collapse the universe upon itself. > How can something with infinite density be infinitely hot? > It would seem so only by extrapolating the equations relating temperature and density of a perfect gas to zero volume. > Another related question is: if a "singularity" shows up in an equation > (as is claimed to happen in some of Einstein's equations), is this not a > sure sign that something in the equation is wrong? Like dividing by > zero, somewhere? No. It just means that there's no quick and easy solution. > As I am neither a mathematician nor a physicist, it may well be that Where forth thou knows not, speakest not. -- Wittenstein > I've got the concept of "infinity" wrong. I would really appreciate it > if someone in this forum can point out to me where my understanding is > wrong (and provide correct interpretations of the term)! > You've got it wrong when you took infinity out of abstract math and tried to conceive it physically. > References to published papers (accessible on line), especially papers > showing what the "Einstein Singularities" are, would be very much > appreciated! > Don't ask, don't tell. (Don't you ask, everybody else don't tell.) You're taking on more than you can chew and it would obscurate your gibberish with mouthfuls of higher order baloney. On the other hand, you seem well prepared to understand theological infinity; hence you should post your infinite droodles in a philosophy newsgroup. > Henry Norman > Riddle of the day. Is hot air a perfect gas?
From: Sam Wormley on 15 Mar 2010 08:53 On 3/15/10 2:34 AM, MicroTech wrote: > In physics (and cosmology) I quite often see references to > "singularities" (as inside "black holes" and as the origin of the so > called "big bang") as being "points with no size, of infinite mass, > infinite density, infinite temperature, and infinite pressure" (or > something to this effect). Who is claiming BB singularity these days? No Center http://www.astro.ucla.edu/~wright/nocenter.html http://www.astro.ucla.edu/~wright/infpoint.html Also see Ned Wright's Cosmology Tutorial http://www.astro.ucla.edu/~wright/cosmolog.htm http://www.astro.ucla.edu/~wright/cosmology_faq.html http://www.astro.ucla.edu/~wright/CosmoCalc.html WMAP: Foundations of the Big Bang theory http://map.gsfc.nasa.gov/m_uni.html WMAP: Tests of Big Bang Cosmology http://map.gsfc.nasa.gov/m_uni/uni_101bbtest.html
From: JT on 15 Mar 2010 09:19
On 15 mar, 13:53, Sam Wormley <sworml...(a)gmail.com> wrote: > On 3/15/10 2:34 AM, MicroTech wrote: > > > In physics (and cosmology) I quite often see references to > > "singularities" (as inside "black holes" and as the origin of the so > > called "big bang") as being "points with no size, of infinite mass, > > infinite density, infinite temperature, and infinite pressure" (or > > something to this effect). > > Who is claiming BB singularity these days? Is there a newsletter so i can follow the day by day changes of our universe? It seem so moldable like our minds create it heheheheheheh Well cosmological and physical science should have a newsletter where all new reviewed and accepted changes to the physic of universe is acknowledged. I want the *flat earth report* on my doorstep, no in my inbox. JT > No Center > http://www.astro.ucla.edu/~wright/nocenter.html > http://www.astro.ucla.edu/~wright/infpoint.html > > Also see Ned Wright's Cosmology Tutorial > http://www.astro.ucla.edu/~wright/cosmolog.htm > http://www.astro.ucla.edu/~wright/cosmology_faq.html > http://www.astro.ucla.edu/~wright/CosmoCalc.html > > WMAP: Foundations of the Big Bang theory > http://map.gsfc.nasa.gov/m_uni.html > > WMAP: Tests of Big Bang Cosmology > http://map.gsfc.nasa.gov/m_uni/uni_101bbtest.html |