JohnSSM Posted January 10, 2015 Author Posted January 10, 2015 r is the distance from the center of the mass sphere. So, again, I stipulated keeping the test particle in the same spot. rs won't change because Mordred specifically said we're keeping the mass the same. When mordred said a shrink in volume, he implied a smaller r... You dont need a test particle if you know GR
Robittybob1 Posted January 10, 2015 Posted January 10, 2015 Here read it for your self The Schwarzschild radius (sometimes historically referred to as the gravitational radius) is the radius of a sphere such that, if all the mass of an object were to be compressed within that sphere, the escape speed from the surface of the sphere would equal the speed of light. An example of an object smaller than its Schwarzschild radius is a black hole. Once a stellar remnant collapses below this radius, light cannot escape and the object is no longer directly visible.[1] It is a characteristic radius associated with every quantity of mass. The Schwarzschild radius was named after the German astronomer Karl Schwarzschild who calculated this exact solution for the theory of general relativity in 1916. http://en.m.wikipedia.org/wiki/Schwarzschild_radius Just clear up one thing please. Is the event horizon the same thing as the Schwarzschild radius?
ydoaPs Posted January 10, 2015 Posted January 10, 2015 When mordred said a shrink in volume, he implied a smaller r... No, mordred didn't. r isn't the radius of the massive sphere. It's the test particle's distance from the center of the sphere. You dont need a test particle if you know GR Oh? Do tell.
JohnSSM Posted January 10, 2015 Author Posted January 10, 2015 Just clear up one thing please. Is the event horizon the same thing as the Schwarzschild radius? As much as it can be Tell me what the test particle is for please?
Robittybob1 Posted January 10, 2015 Posted January 10, 2015 So you can compare apples to apples. Were they the same apples or different apples?
JohnSSM Posted January 10, 2015 Author Posted January 10, 2015 What do you think he meant by "shrink in volume"? Were they the same apples or different apples? When you stuff mass into the volume its different apples...
ydoaPs Posted January 10, 2015 Posted January 10, 2015 As much as it can be Tell me what the test particle is for please? The same thing it's always for. From Wikipedia: "In metric theories of gravitation, particularly general relativity, a test particle is an idealized model of a small object whose mass is so small that it does not appreciably disturb the ambient gravitational field. According to the Einstein field equation, the gravitational field is locally coupled not only to the distribution of non-gravitational mass-energy, but also to the distribution of momentum and stress (e.g. pressure, viscous stresses in a perfect fluid). In the case of test particles in a vacuum solution or electrovacuum solution, this turns out to imply that in addition to the tidal acceleration experienced by small clouds of test particles (spinning or not), spinning test particles may experience additional accelerations due to spin-spin forces.[2]"
JohnSSM Posted January 10, 2015 Author Posted January 10, 2015 (edited) You dont need a test particle to figure space curvature...thats what GR does Im just saying...if youre looking to a test particle for the effects of gravity change, you must not know how to figure them with GR...cuz i heard GR does it perfectly...and you dont need 2 masses Edited January 10, 2015 by JohnSSM
Robittybob1 Posted January 10, 2015 Posted January 10, 2015 So, the black hole Earth and the regular Earth will both have a Schwartzchild metric. [math]c^2\tau^2=(1-\frac{r_s}{r})c^2dt^2-(1-\frac{r_s}{r})^{-1}dr^2-r^2(d\theta^2+\sin^{2}\theta{d}\phi^2)[/math] If we're keeping the mass the same, making an Earth black hole rather than an Earth+ black hole, then the metrics will be the same since rs will be the same. Now, you're talking about adding in energy. We're not talking about an Earth black hole anymore. We're talking about an Earth+acraploadofenergy blackhole which has a different rs than Earth. However, that's not what you said when I responded to you saying that it was false. What you said was: That's the Earth blackhole, not the Earth+acraploadofenergy black hole. I maintain that the quoted post is incorrect. Isn't it take out a hell of a lot of energy?
JohnSSM Posted January 10, 2015 Author Posted January 10, 2015 Swarzenchild is clear...for every amount of mass, there will be a certain radius, that when compressed to, will create a BH... Isn't it take out a hell of a lot of energy? We dont care how much energy it takes...it happens all the time...where does the compressive force come from if we arent supplying it? how does nature pull it off? (Nature pulls it off all the time...)
ydoaPs Posted January 10, 2015 Posted January 10, 2015 You dont need a test particle to figure space curvature...thats what GR does Where, exactly, do you think the metric comes from? [math]R_{\mu\nu}-\frac{1}{2}Rg_{\mu\nu}+\Lambda{g_{\mu\nu}}=\frac{8\pi{G}}{c^4}T_{\mu\nu}[/math] That [math]g_{\mu\nu}[/math] is the metric. It's a matrix whose diagonal is composed of the coefficients of the distance relation. In this case, the Schwartzchild metric I posted above. As I said, r is the distance of a test particle from the center of the sphere of mass. It's abundantly clear that you don't actually know what GR 'does' given the post I quoted in this post. 1
JohnSSM Posted January 10, 2015 Author Posted January 10, 2015 Where, exactly, do you think the metric comes from? [math]R_{\mu\nu}-\frac{1}{2}Rg_{\mu\nu}+\Lambda{g_{\mu\nu}}=\frac{8\pi{G}}{c^4}T_{\mu\nu}[/math] That [math]g_{\mu\nu}[/math] is the metric. It's a matrix whose diagonal is composed of the coefficients of the distance relation. In this case, the Schwartzchild metric I posted above. As I said, r is the distance of a test particle from the center of the sphere of mass. It's abundantly clear that you don't actually know what GR 'does' given the post I quoted in this post. What im saying is that you didnt understand his postulate completely...if you did, then youll have to account for the sentence "shrink in volume"? He said it within that statement...what did it mean to you? if you can run GR on empty space that will never exist and it works. for sure we can run it on one massive body...whatever exists in spacetime is the same massive body... -1
Mordred Posted January 10, 2015 Posted January 10, 2015 Actually I see your point YdoaPs still calculating it through
JohnSSM Posted January 10, 2015 Author Posted January 10, 2015 (edited) Actually I see your point YdoaPs still calculating it through Did you mean a shrink in volume when you said a shrink in volume? Edited January 10, 2015 by JohnSSM
Robittybob1 Posted January 10, 2015 Posted January 10, 2015 (edited) Swarzenchild is clear...for every amount of mass, there will be a certain radius, that when compressed to, will create a BH... We dont care how much energy it takes...it happens all the time...where does the compressive force come from if we arent supplying it? how does nature pull it off? (Nature pulls it off all the time...) Well you won't get there by adding energy, matter fluffs up when energy is added. Gravitational collapse will be associated with heat and that heat will needed to radiate away and then when it cools the pressure will increase more atom nuclei will fuse more heat will be released and on it goes for billions of years till a BH happens. There are some fusions that need added energy, so you might have a type of energy consuming reaction that by passes cooling. I'll have to refresh that point. Edited January 10, 2015 by Robittybob1
JohnSSM Posted January 10, 2015 Author Posted January 10, 2015 (edited) with a large enough lever, I could move the planet...with a large enough trash compactor with large enough power, I can make fusion...or a black hole Well you won't get there by adding energy, matter fluffs up when energy is added. Gravitational collapse will be associated with heat and that heat will needed to radiate away and then when it cools the pressure will increase more atom nuclei will fuse more heat will be released and on it goes for billions of years till a BH happens. Why mopes the black hole occur in that instance? What makes it occur? Edited January 10, 2015 by JohnSSM
Mordred Posted January 10, 2015 Posted January 10, 2015 Yes but a shrink in volume is also a change in the thermodynamic state. Which I believe is the point Ydoaps is making. My statement of change in mass would be incorrect. The increase in density would increase the mass as the pressure and temperature increases.
JohnSSM Posted January 10, 2015 Author Posted January 10, 2015 Yes but a shrink in volume is also a change in the thermodynamic state. Which I believe is the point Ydoaps is making. My statement of change in mass would be incorrect. The increase in density would increase the mass as the pressure and temperature increases. Well yeah, it would start fusion...thats what's happens on your way to becoming a black hole... then fusion begins to make really heavy elements...thats how the density of these things can really get exponential...you started with a big cloud of hydrogen and such light things...and end up with iron, steel...etc the earth makes enough pressure to make molten lava...far short from fusion... But the schwatrman thing it totally on the level right? any mass has a certain radius, that if reduced (in whatever theoretical way) will create a BH if you retain all the mass...
Robittybob1 Posted January 10, 2015 Posted January 10, 2015 Well yeah, it would start fusion...thats what's happens on your way to becoming a black hole... then fusion begins to make really heavy elements...thats how the density of these things can really get exponential...you started with a big cloud of hydrogen and such light things...and end up with iron, steel...etc the earth makes enough pressure to make molten lava...far short from fusion... But the schwatrman thing it totally on the level right? any mass has a certain radius, that if reduced (in whatever theoretical way) will create a BH if you retain all the mass... That's the "theory" - the Schwarzschild radius.
JohnSSM Posted January 10, 2015 Author Posted January 10, 2015 That's the "theory" - the Schwarzschild radius. If you understand my very first entry of this thread, you can see me describe this radius...I had heard that black holes are a result of compressive energy and also rationed it very easy myself, but had not heard or read this thoery...true
Robittybob1 Posted January 10, 2015 Posted January 10, 2015 If you understand my very first entry of this thread, you can see me describe this radius...I had heard that black holes are a result of compressive energy and also rationed it very easy myself, but had not heard or read this thoery...true Ambitious!
JohnSSM Posted January 10, 2015 Author Posted January 10, 2015 (edited) If you understand my very first entry of this thread, you can see me describe this radius...I had heard that black holes are a result of compressive energy and also rationed it very easy myself, but had not heard or read this thoery...true Suns being on their way to being black holes is kinda a popular idea I think...not many make it comparitively Ambitious! It not ambitious when its allready been done...its something else I find it so interesting that most of the time, we as humans are mostly under the pressures of our own vectors and energies too...we meet certain folks, its changes our vectors and energies...and often get caught up orbiting sources of energy that we can never overcome...like lobbying...and religion..and network TV...material possessions! personal power! delusions of grandeur are relativity at work... panic attacks are black holes and xanax weakens the field... Edited January 10, 2015 by JohnSSM
ajb Posted January 10, 2015 Posted January 10, 2015 You dont need a test particle to figure space curvature...thats what GR does A related question here is; given the geodesics, so the paths particles will take in a space-time under just the influence of gravity can you recover the full geometry, i.e. reconstruct the metric? The short answer is no, there are different metrics that can give rise to the same metrics. So in this sense the geodesics, although they track out the local geometry do not give you the full structure. Now when testing GR people usually have a metric or a class of them given and you see if what you observe matches the predictions. For example gravitational lensing.
JohnSSM Posted January 10, 2015 Author Posted January 10, 2015 (edited) A related question here is; given the geodesics, so the paths particles will take in a space-time under just the influence of gravity can you recover the full geometry, i.e. reconstruct the metric? The short answer is no, there are different metrics that can give rise to the same metrics. So in this sense the geodesics, although they track out the local geometry do not give you the full structure. Now when testing GR people usually have a metric or a class of them given and you see if what you observe matches the predictions. For example gravitational lensing. Just under the influence of gravity? The paths that particles take is a geometrical effect of their own vectors and energies...as an individual and as a group...an individual particle may only spin if there is not another particle influencing its' relative vectors and energies...but it's relative vectors and energies change the shape of gravity, geometery and GR on its own... Just under the influence of gravity? The paths that particles take is a geometrical effect of their own vectors and energies...as an individual and as a group...an individual particle may only spin if there is not another particle influencing its' relative vectors and energies...but it's relative vectors and energies change the shape of gravity, geometery and GR on its own... Wait a second here...why does anyone have to test for GR if it is expected to be 100 percent reliable equations? Is this basically when youre using GR to prove some other unknown? IS there anything other than the equations of general relativity that effect gravity? Edited January 10, 2015 by JohnSSM
ajb Posted January 10, 2015 Posted January 10, 2015 Just under the influence of gravity? The paths that particles take is a geometrical effect of their own vectors and energies...as an individual and as a group...an individual particle may only spin if there is not another particle influencing its' relative vectors and energies...but it's relative vectors and energies change the shape of gravity, geometery and GR on its own... Here I of course meant test particle. 1
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