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Natural Science Forum / Physics / Relativity / June 2005Neutrino's Energy Has Gravity
If neutrinos don't have mass they still have energy. They are not nothing! According to GR by their energy they will always effect the gravity of the universe. How hard is that? Nick: >If neutrinos don't have mass they still have energy. What's your point? >They are not nothing! If neutrinos were nothing, the wouldn't be called neutrinos. Is this what passes for profound on your planet? >According to GR by their energy they will always effect the gravity of >the universe. > >How hard is that? Since you evidently didn't think it was very obvious, you must have found it real hard. To the rest of the world that has evolved beyond bacteria, it was obvious. Why don't you go post on your 7th grade sci.fi forum? > If neutrinos don't have mass they still have energy. > They are not nothing! [quoted text clipped - 3 lines] > > How hard is that? For Macromitch, who does neither math nor physics, it's not only "hard", it's impossible. We've been through this before. In GTR, kinetic energy "gravitates" differently from that of inertial energy. Kinetic energy goes the way of a null geodesic. Pure geometry. No dynamics. If the neutrino's are uniformly distributed, there will be no gravitational field, It cancels out, but there will be a uniform gravitational potential for which dT / dr isn't unity. [Old Man] CMBR is spread out. Will it not effect the gravity of the universe? > CMBR is spread out. Will it not effect the gravity of the universe? If CMBR is "spread out", that is, if its energy density is uniform, then gravity due to CMBR cancels everywhere. However, even in the absence of gravitational force, there a uniform gravitational potential is present, which, in GTR, causes the ratio, dT / dt = [proper time interval] / [coordinate time interval] to deviate from one. [Old Man] > If CMBR is "spread out", that is, if its energy density is > uniform, then gravity due to CMBR cancels everywhere. Not really. It still affects the curvature and expansion of the universe. The Friedman models assume the energy density of everything is uniform, which it is at large enough scales. > However, even in the absence of gravitational force, there > a uniform gravitational potential is present, which, in GTR, [quoted text clipped - 3 lines] > > to deviate from one. This depends on what coordinate system you're using, and what the worldline of your test particle is. Gravity is not a scalar field. -- Ben Nick <macromitch@yahoo.com> wrote in <1117085358.688898.247070@g47g2000cwa.googlegroups.com> on Thursday 26 May 2005 00:29 posted to sci.physics.relativity: > If neutrinos don't have mass they still have energy. > They are not nothing! They would only be like photons in that respect. > According to GR by their energy they will always effect the gravity of > the universe. No, even in GR gravity is produced by matter, which always has mass, since mass is defined to be the amount of matter. Photons do not produce gravity, since they have no mass, even though they have energy and momentum. > How hard is that? Well, the discussion may be moot anyway, since most physicists think that neutrinos have mass after all, based on the Superkamiokande results.  Signature// The TimeLord says: // Pogo 2.0 = We have met the aliens and they are us! Dear The TimeLord: > Nick <macromitch@yahoo.com> wrote in > <1117085358.688898.247070@g47g2000cwa.googlegroups.com> on [quoted text clipped - 5 lines] > > They would only be like photons in that respect. Neutrinos as a family are *required* to have a small amount of mass. >> According to GR by their energy they will always >> effect the gravity of the universe. > > No, even in GR gravity is produced by matter, Energy also contributes to gravitation. > which always has mass, since > mass is defined to be the amount of matter. > Photons do not produce gravity, Yes they do. It is just not a large contribution. > since they have no mass, In pairs, in their center of momentum frame, they do have rest mass. > even though they have energy and momentum. > [quoted text clipped - 4 lines] > have mass after all, based on the > Superkamiokande results. David A. Smith > Nick <macromitch@yahoo.com> wrote in > <1117085358.688898.247070@g47g2000cwa.googlegroups.com> on Thursday 26 May [quoted text clipped - 9 lines] > > No, even in GR gravity is produced by matter, Err, not only. The source for gravity in GR is the energy-momentum tensor. Energy "produces" gravity, pressure does, too. > which always has mass, since > mass is defined to be the amount of matter. Photons do not produce gravity, They do. What do *you* think why one considers the radiation density in cosmology? > since they have no mass, even though they have energy and momentum. And that's enough for them to "produce" gravity. >>How hard is that? > > Well, the discussion may be moot anyway, since most physicists think that > neutrinos have mass after all, based on the Superkamiokande results. And the SNO results. And some others. Bye, Bjoern >> According to GR by their energy they will always effect the gravity of >> the universe. >No, even in GR gravity is produced by matter, which always has mass, since >mass is defined to be the amount of matter. Photons do not produce gravity, >since they have no mass, even though they have energy and momentum. No. I'm pretty sure you're wrong about that. Photons *do* produce gravity. And of course, so do neutrinos. In GR, space-time curvature (gravity) is produced by any form of energy. Energy and mass are related by Einstein's famous formula. Another way to think about this is to ask yourself how anything could be affected by a force, and not have an effect back on the force. Particles with no electric charge are not affected by the EM field, and do not produce one. If you had a particle with no energy, no mass, and no momentum, THEN it would not be subject to gravity, and would not produce any. I cannot think of what such a thing would be, and still be real. Perhaps Bohm's 'pilot waves', which are empty waves (carry no energy) that somehow direct the probability of where you detect quantum particles. But it's a mystery to me how they are expected to do this without energy. That's probably why nobody pays any attention to that idea. It's totally incompatible with SR and GR. |
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