Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Mike_Cobley on 25/06/2018 08:16:12
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Hey all
Quick question for you. I hear all the time, 'the elusive gravity particle' . But why do we even need one? Doesn't Einstein's General theory describe gravity as mass warping space/time. So, i thought of gravity more like rivers within the sea. You get pulled 'along' but there is no particle per-se that does that pulling.
Or am i completely off base here?
Rgds
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why do we even need (a graviton)?
You can understand an electric current, and wire together batteries and electric motors without knowing anything about an "electric particle". In fact, Michael Faraday did just that.
But when you get down to steering electrons traveling through a vacuum (needed to build an old-fashioned TV tube) or manipulating small numbers of electrons and their precise energy levels (needed to build a transistor), you need to understand the electric particle (electron) in far more detail.
You can build things as big as a Solar System, or as small as a neutron star (which has pretty much the same mass) using Einstein's General theory of relativity. You can detect gravitational waves using the same theory.
But when you get down to the gravitational field close to the event horizon of a black hole, Einstein's General Relativity comes up with infinities that physicists have not been able to get around. So physicists (including Stephen Hawking) want to know more about what happens in this environment.
Since quantum theory has managed to resolve some other contradictions in electromagnetism, it is thought that a quantum theory might be able to resolve some contradictions in gravity.
"Graviton" is the name given to this hypothetical particle. There is even a quantum description of this hypothetical particle that would have the right properties: a spin-2 boson.
Most physicists think that a Graviton probably exists, but its energy is so low that current technologies cannot detect individual gravitons. Assuming the graviton exists, we can generate them easily enough by accelerating small masses, but they fly off in all directions at the speed of light. Today, we have nothing equivalent to a "gravitational insulator", so we are unable to bend the graviton to our will.
See: https://en.wikipedia.org/wiki/Graviton
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Photons can be reflected. What about gravitons? Can they be deflected by interactions with other particles? This is moot to a large extent since a gravitational field needs no acceleration to exist and have an effect on objects. We can think in terms of virtual gravitons for purposes of theorising but it is much more abstract than that. The field may have quanta but that will not answer the important questions.
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So, if I get this right. Because of the contradictions with gravity, in some situations we need to describe it as a particle to overcome these? Apologies if i miss understood.
Rgds
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Because of the contradictions with gravity, in some situations we need to describe it as a particle to overcome these?
Special Relativity does have contradictions near a black hole.
Theoretical Physicists working on String Theory have constructed a model of a graviton which exactly matches Special Relativity - including the contradictions near a black hole.
I am sure those researchers are now working on a variant of their theory which agrees with Special Relativity wherever we can measure it, but doesn't have contradictions near a black hole.
Unfortunately, finding out what really happens near a black hole may require us to go to a black hole - a trip I, for one would not be volunteering for!
See: https://en.wikipedia.org/wiki/String_theory#Applications_to_quantum_gravity
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If nothing gets out of BH, how does a graviton virtual or otherwise get out. Also if gravitons are radiated by matter away from mass why dont they push other masses away.
Is it better to view vurtual gravitons as appearing in space and being absobed by mass creating an inflow rather than outflow.
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If nothing gets out of BH, how does a graviton virtual or otherwise get out.
Gravitons represent energy propagating away through space at the speed of light.
However, left to itself, the gravitational field around a black hole is a static thing which radiates no energy, so there are no real gravitons.
When an object (like a neutron star) orbits a black hole, gravitational energy is radiated away through space. But you could imagine this as originating from the space between the two objects, rather than being emitted from within the black hole's event horizon.
if gravitons are radiated by matter away from mass why don't they push other masses away
The effects of a single graviton are much like the effects of a gravitational wave (only much, much tinier). The gravitational waves we have detected are effectively just very many in-phase gravitons, arriving in massive bunches.
Gravitational waves don't push matter away, since they are not actually absorbed by matter, and don't deliver any linear momentum.
Gravitational waves act to twist space in one direction, and then twist it back to the original position. They slightly accelerate time, and then decelerate it, back to the original rate. So overall, everything is left back where (and when) it was before the gravitational wave arrived.
See: https://en.wikipedia.org/wiki/Gravitational_wave#Introduction
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Photons can be reflected. What about gravitons?
For something to be a generally useful technology, we need methods to:
1. Manufacture/generate it
2. Manipulate/modify it
3. Monitor/detect/use it
Unfortunately:
1. It takes at least a pair of neutron stars to manufacture a significant number of gravitons. Currently out of our league.
2. Gravitons affect space and time, rather than matter, so they are currently impossible to manipulate
3. Our smallest detectors are about 4 miles long, and even then have extreme problems detecting trillions of gravitons arriving at once, in phase.
So graviton technology is not yet ready for general use by members of the public.
I expect that black holes will deflect gravitons, just like they deflect photons. So maybe one day we may be able to do graviton spectroscopy by diffracting them with an array of micro-black holes?
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@evan_au I thought I'd throw that one in for good measure. ;)
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I think you're right :)
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Very interesting to learn that gravitational waves may be made of gravitons in phase (so like photons in that respect?
Can gravitons be understood as an excitation in a particular wave ? (maybe said gravitational wave?)
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However, left to itself, the gravitational field around a black hole is a static thing which radiates no energy, so there are no real gravitons.
Just to confirm, the graviton spin 2 boson, theorized to exist, https://phys.org/news/2014-03-elusive-graviton.html DOES NOT EXIST.
Are you stating the Graviton is a virtual particle which has a very short life time existing momentarily in space, like a quantum fluctuation of quantum foam.
:) Can you confirm is it the earth/mass/energy that sucks or is it the graviton/virtual particle that sucks :)
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3. Our smallest detectors are about 4 miles long, and even then have extreme problems detecting trillions of gravitons arriving at once, in phase.
Do you view the gravitional waves detected by ligo as an reduced density of gravitons followed by an an increased density of gravitons creating a contraction and expansion of space , OR do you view it as a stretch of space time to view the graviton as being the cause of the apparent curvature of space.
Could the Graviton and Dark Energy be the same thing?
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Very interesting to learn that gravitational waves may be made of gravitons in phase (so like photons in that respect?
Can gravitons be understood as an excitation in a particular wave ? (maybe said gravitational wave?)
Gravitons in a quantum gravity theory would fulfill the same role as photons do in Quantum Electrodynamics.
So in the same way as electromagnetic radiation (light, radio waves, x-rays etc) are made up of photons of particular discreet energies depending on the frequency of the electromagnetic wave, Gravitational waves would be made up of gravitons of discreet energies.
And in the same way as the electromagnetic field is mediated by virtual photons in Quantum Electrodynamics, virtual gravitons would mediate the gravitational field.
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Very interesting to learn that gravitational waves may be made of gravitons in phase (so like photons in that respect?
Can gravitons be understood as an excitation in a particular wave ? (maybe said gravitational wave?)
Gravitons in a quantum gravity theory would fulfill the same role as photons do in Quantum Electrodynamics.
So in the same way as electromagnetic radiation (light, radio waves, x-rays etc) are made up of photons of particular discreet energies depending on the frequency of the electromagnetic wave, Gravitational waves would be made up of gravitons of discreet energies.
And in the same way as the electromagnetic field is mediated by virtual photons in Quantum Electrodynamics, virtual gravitons would mediate the gravitational field.
So there could possibly be more or less energetic varieties of gravitons ?
And anti gravitons might be included in the particle soup?
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3. Our smallest detectors are about 4 miles long, and even then have extreme problems detecting trillions of gravitons arriving at once, in phase.
Do you view the gravitional waves detected by ligo as an reduced density of gravitons followed by an an increased density of gravitons creating a contraction and expansion of space ,
No. That would be the equivalent of saying that an electromagnetic wave is caused by a varying density of photons.( such a varying density would actually be the result of an additional modulation of the electromagnetic waves, such as we use in AM radio, where we modulate the strength of the carrier wave to encode information onto it.) OR do you view it as a stretch of space time to view the graviton as being the cause of the apparent curvature of space.
the frequency/wavelength would be due to the energy of the discreet gravtions, while the magnitude would be due to number of gravitons per sec.( The number of gravitons arriving per sec can be constant and you would still measure a sequential compression and stretching of spacetime with a frequency equal to that of the individual gravitons)Could the Graviton and Dark Energy be the same thing?
No.
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Very interesting to learn that gravitational waves may be made of gravitons in phase (so like photons in that respect?
Can gravitons be understood as an excitation in a particular wave ? (maybe said gravitational wave?)
Gravitons in a quantum gravity theory would fulfill the same role as photons do in Quantum Electrodynamics.
So in the same way as electromagnetic radiation (light, radio waves, x-rays etc) are made up of photons of particular discreet energies depending on the frequency of the electromagnetic wave, Gravitational waves would be made up of gravitons of discreet energies.
And in the same way as the electromagnetic field is mediated by virtual photons in Quantum Electrodynamics, virtual gravitons would mediate the gravitational field.
So there could possibly be more or less energetic varieties of gravitons ?
in a quantum gravity theory, this would be a requirement. Look at the LIGO detection of gravitational waves, and you will see a correlation between wave strength and frequency. This is because as the BHs orbited closer and closer to each other, the frequency of the Gravitation waves (which was tied to the Orbital period of the BHs) became higher and higher along with the strain measured by LIGO. Higher frequency Gravitational waves are more energetic in the same way that higher frequency electromagnetic waves are. In a quantum gravity theory, this would mean that higher frequency gravitons are more energetic than lower frequency ones
And anti gravitons might be included in the particle soup?
No, because, like photons, gravitons would be their own anti-particle.
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If antimatter interacts with gravity in the same way as matter does, and it's my guess that it does, then gravity was instrumental in bringing both types together to annihilate in the early stages of the big bang. That there is an asymmetry between matter and antimatter is a mystery. If there were less of an effect of gravity on antimatter by even a tiny amount, then that would be interesting. Very unlikely though.
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Are you stating the Graviton is a virtual particle which has a very short life time existing momentarily in space, like a quantum fluctuation of quantum foam.
All virtual particles (including virtual photons and virtual gravitons) have a short lifetime and limited range, limited by the Heisenberg Uncertainty Principle.
However, real gravitons propagate away to infinity, as oscillations on the gravitational field. This is what LIGO detected. (And real photons propagate away to infinity, as oscillations on the electromagnetic field. This is what telescopes detect.)
https://en.wikipedia.org/wiki/Virtual_particle
Look at the LIGO detection of gravitational waves, and you will see a correlation between wave strength and frequency
But correlation does not prove causation.
In this case, both the amplitude increase and frequency are also correlated with a third variable: distance.
- As the black holes spiral closer together, their distance decreases
- When they are closer, their orbital period decreases (ie the frequency increases)
- When they are closer, much more power is emitted as gravitational waves
But the trend is certainly valid - gravitational waves of higher frequency (ie gravitons of shorter wavelength) will carry more momentum. The same relationship is true of photons.
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At the moment I am investigating wavelength as it relates to the time dilation of the source of the radiation. So a wave strength and frequency correlation may be explainable.
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However, real gravitons propagate away to infinity, as oscillations on the gravitational field. This is what LIGO detected. (And real photons propagate away to infinity, as oscillations on the electromagnetic field. This is what telescopes detect.)
LIGO detected gravitational waves as predicted by EFE not gravitons. Gravitons are theorized to exist and have such low energy levels that we can not detect them with todays technology.
Bosons can not escape a BH, a graviton is a 2 spin boson how can it get out of a BH. A gamma ray cannot escape the event horizon of a BH and it has significantly more energy.
But the trend is certainly valid - gravitational waves of higher frequency (ie gravitons of shorter wavelength) will carry more momentum. The same relationship is true of photons.
Gravitational waves definitely exist gravitons might not exist, and might not have enough energy to escape a BH.
That there is an asymmetry between matter and antimatter is a mystery.
Why would you think an asymmetry should exist? An electron and positron when colliding produce 2 gamma rays(bosons) with 511eV of energy, the energy is not destroyed, it just changes form, the BB theory started with lots of radiation(bosons). For a zero energy universe you need +ve energy and -ve energy, not matter and antimatter. One way of achieving this is to regard dark energy (expansion of space) and gravity (contraction of space) as manifestations of one form energy and all other forms of energy as opposite to this. Conversely to the above with this view the graviton(virtual particle) flows towards mass not away and is a virtual particle.
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However, real gravitons propagate away to infinity, as oscillations on the gravitational field. This is what LIGO detected. (And real photons propagate away to infinity, as oscillations on the electromagnetic field. This is what telescopes detect.)
LIGO detected gravitational waves as predicted by EFE not gravitons. Gravitons are theorized to exist and have such low energy levels that we can not detect them with todays technology.
If gravitons exist (Gravity can be explained with a quantum theory), then gravitational waves would consist of gravitons.
Bosons can not escape a BH, a graviton is a 2 spin boson how can it get out of a BH. A gamma ray cannot escape the event horizon of a BH and it has significantly more energy.
Gravitons can't, but since gravity would be mediated by virtual gravitons, this is no different from the fact that photons can't escape a BH, yet a BH can have a charge and an electromagnetic field mediated by virtual photons.
Gravitational waves definitely exist gravitons might not exist, and might not have enough energy to escape a BH.
Gravitational waves can't escape a BH either (By this I mean that gravitational waves cannot get out from inside the event horizon anymore than electromagnetic waves can.)
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The asymmetry problem explained at cern.
https://home.cern/topics/antimatter/matter-antimatter-asymmetry-problem
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I expect that black holes will deflect gravitons, just like they deflect photons. So maybe one day we may be able to do graviton spectroscopy by diffracting them with an array of micro-black holes?
Just checking! The gravitational field is scalar. If the gravitational field is composed of gravitons, the gravitons don’t have directionality. If this is the case; how could they be deflected?
However, real gravitons propagate away to infinity, as oscillations on the gravitational field. This is what LIGO detected. (And real photons propagate away to infinity, as oscillations on the electromagnetic field. This is what telescopes detect.)
By analogy with water waves, one might reason that individual gravitons within a gravitational wave would not propagate in the direction of the apparent motion of the wave. Only energy would propagate in that way. Again; how could the gravitons be deflected?
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If gravitons exist (Gravity can be explained with a quantum theory), then gravitational waves would consist of gravitons.
Gravitons can't, but since gravity would be mediated by virtual gravitons, this is no different from the fact that photons can't escape a BH, yet a BH can have a charge and an electromagnetic field mediated by virtual photons.
Am I be correct in thinking that "virtual gravitons" and "virtual photons" are simply a convenient mathematical way of explaining how forces are transmitted and that they may not actually exist as virtual particles at a point in space???
The magnetic field and electric charge of a BH is normally attributed to the accretion disc, are you saying a magnetic field can escape from inside a BH ? .
Gravitational waves can't escape a BH either (By this I mean that gravitational waves cannot get out from inside the event horizon anymore than electromagnetic waves can.)
Yes I think I understand you. The distortion of space time increases towards a BH, two BH's orbiting each other modulate space time causing the gravitational waves.
The asymmetry problem explained at cern.
https://home.cern/topics/antimatter/matter-antimatter-asymmetry-problem
That link just points out there is a problem with the current model. ie it does not fit the observed universe.
Just checking! The gravitational field is scalar. If the gravitational field is composed of gravitons, the gravitons don’t have directionality. If this is the case; how could they be deflected?
Would gravitational frame dragging be of any consequence to your question https://www.space.com/456-einstein-warped-view-space-confirmed.html
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The magnetic field and electric charge of a BH is normally attributed to the accretion disc, are you saying a magnetic field can escape from inside a BH ?
According to Special Relativity, Black Holes only have 3 properties that are detectable external to the black hole: Mass, Angular Momentum & electric charge.
These properties are detectable from black holes with no accretion disk.
See: https://en.wikipedia.org/wiki/No-hair_theorem
(Let's ignore information paradoxes and hypothetical magnetic monopoles for now - these are not covered by Special Relativity.)
Black holes have spin and electric charge, yet they are thought to have no magnetic field of their own - perhaps because the electric charge is concentrated at the singularity at the center?
However, if you have a moving electric charge, that movement creates a magnetic field (whether it be a moving electron or a moving black hole). But if you are stationary near a black hole, you would not detect a magnetic field.
On the other hand, accretion disks around a black hole consist of rapidly spinning conductive plasma disk which drags magnetic fields with it, and tangles them up, releasing huge amounts of energy as particle jets emanating from the poles (but still only a fraction of the energy of the matter falling into the black hole). An accretion disk is something that you find outside the event horizon, so the particles and magnetic field field don't need to escape from within the black hole.
See: https://en.wikipedia.org/wiki/Accretion_disk#Magnetic_fields_and_jets
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Interesting link, Dead Cat, thanks.
On an initial scan, I can't see that it says anything about the possible motion of a scalar field.
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By analogy with water waves, one might reason that individual gravitons within a gravitational wave would not propagate in the direction of the apparent motion of the wave. Only energy would propagate in that way. Again; how could the gravitons be deflected?
I may be wrong here but virtual gravitons would be absorbed by mass and not reflected, whereas the water wave energy is not absorbed and can be reflected by a sea cliff and cause confused waves. Also water is not a virtual particle it exists for a long time. A modulation in the density of virtual particles might be analogous to a water wave, compressing and releasing and contracting.
All of space is full of virtual particles as predicted by the HUP. There is no such thing a a perfect vacuum, and space time does not exist without the appearance of virtual particles.
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I may be wrong here but virtual gravitons would be absorbed by mass and not reflected,
Were we talking about virtual gravitons (whatever they might be)?
whereas the water wave energy is not absorbed and can be reflected by a sea cliff and cause confused waves.
I don’t think you can compare the motion of water once a wave has broken against a cliff with the smooth passage of an unbroken wave. The mechanics would be totally different.
Also water is not a virtual particle it exists for a long time.
I was responding to:
However, real gravitons propagate away to infinity, as oscillations on the gravitational field…
In order to do that, they would have to exist for a very long time. Infinitely long (?).
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I may be wrong here but virtual gravitons would be absorbed by mass and not reflected,
Were we talking about virtual gravitons (whatever they might be)?
whereas the water wave energy is not absorbed and can be reflected by a sea cliff and cause confused waves.
I don’t think you can compare
However, real gravitons propagate away to infinity, as oscillations on the gravitational field…
In order to do that, they would have to exist for a very long time. Infinitely long (?).
A contraction of space and the density of virtual particles, followed by an expansion of space and an increase of virtual particles could be viewed as infinite wave rippling through space. The virtual graviton could also be viewed as dark energy perhaps
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infinite wave rippling through space.
I always have reservations about using “infinite” to describe some finite thing, or process, for which we can see no end. However, as long as we acknowledge that we are talking about our perception, rather than the actual nature of the object/process, I know what you mean.
The virtual graviton could also be viewed as dark energy perhaps
Graviton = so far undetected particle.
Virtual particle = not a particle at all.
Dark energy = something of which we have only indirect evidence.
You could have a very valid point, but I suspect that convincing maths and/or hard evidence would be needed to drag it out of the realms of speculation.
Keep speculating, though, I’m a great fan of speculation. :)
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infinite wave rippling through space.
The virtual graviton could also be viewed as dark energy perhaps
Graviton = so far undetected particle.
Virtual particle = not a particle at all.
Dark energy = something of which we have only indirect evidence.
You could have a very valid point, but I suspect that convincing maths and/or hard evidence would be needed to drag it out of the realms of speculation.
Keep speculating, though, I’m a great fan of speculation. :)
The graviton is speculation, and most likely does not exist. Virtual particles which are vacuum fluctuations do exist as proven by the casimir effect and suggested by the well established HUP.
Virtual photons mediating the magnetic field, or a gravitational field, are virtual particles otherwise generically known as quantum fluctuations.
Dark energy as a result of quantum fluctuations out of the vacuum of space is an active area of research. Yes there are mathematical problems, as there appears to be with relativity predicting random amounts of dark matter to explain the apparent additional forces required at the outer edges of spiral galaxies to hold them together.
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Virtual particles which are vacuum fluctuations do exist as proven by the casimir effect and suggested by the well established HUP.
I'm not questioning the vacuum fluctuations, but are they actually particles?
Dark energy as a result of quantum fluctuations out of the vacuum of space is an active area of research.
No quarrel there, either, but string theory is also an active area of research. As far as I am aware, they would both benefit from some practical/physical support.
Please don't think I'm knocking speculation or thinking outside the box, just commenting on the fact that a bit of back-up is a good thing.
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If you feel that the gravitational field does not have quanta then you have to explain an alternative cause of gravitational waves. You can't just say they don't exist.
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Are quanta and particles necessarily the same thing? I'm struggling to think of a quantum that is not considered to be a particle. Virtual particles are as near as I can get.
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Hey all
Quick question for you. I hear all the time, 'the elusive gravity particle' . But why do we even need one? Doesn't Einstein's General theory describe gravity as mass warping space/time.
No. It describes gravitational tidal forces as a curvature in spacetime. But that's not all there is to gravity. You can have a uniform gravitational field which has zero spacetime curvature. Another example is described in the American Journal of physics. I.e. See
Cosmic strings: Gravitation without local curvature by T.M. Helliwell, Am. J. Phys.,55(5), May (1987)
Abstract: http://dx.doi.org/10.1119/1.15145http://dx.doi.org/10.1119/1.15145
Cosmic strings are very long, thin structures which might stretch over vast reaches of the universe. If they exist, they would have been formed during phase transitions in the very early universe. The space‐time surrounding a straight cosmic string is flat but nontrivial: A two‐dimensional spatial section is a cone rather than a plane. This feature leads to unique gravitational effects. The flatness of the cone means that many of the gravitational effects can be understood with no mathematics beyond trigonometry. This includes the observational predictions of the double imaging of quasars and the truncation of the images of galaxies.
The article has an odd title since all curvature is, at a minimum, local.
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Are quanta and particles necessarily the same thing? I'm struggling to think of a quantum that is not considered to be a particle. Virtual particles are as near as I can get.
Quanta is the plural form of quantum. A quantum doesn't need to be a particle. See definition at:
https://en.oxforddictionaries.com/definition/quantum
It just means "discrete amount." For example: A harmonic oscillator has discreet energy levels in which it can be in. Those levels are said be quantized.
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Quanta is the plural form of quantum.
That's why I said, "are quanta"......and ....."a quantum".
I am always a little cautious about using dictionary definitions in scientific discussions. I don't remember if it was you or Alan who cautioned against that.
Thanks for the clarification, though.
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..... A harmonic oscillator has discreet energy levels in which it can be in. Those levels are said be quantized.
I know very little about harmonic oscillators. Can their "energy levels" interact/interfere with one another?
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I know very little about harmonic oscillators. Can their "energy levels" interact/interfere with one another?
Probably the simplest, most familiar harmonic oscillator is the pendulum.
The pendulum will swing (oscillate) with a frequency which is related to the length of the string, and the strength of Earth's gravity.
If you tie several pendulums (penduli??) to a common string, they will interact with each other, transferring energy from one pendulum to the other via the string. Depending on the relative frequencies, you can get behaviors like:
- 1 Pendulum: Simple Harmonic motion
- 2 Pendulums: They transfer energy backwards and forwards between them, with first one swinging, then the other swinging
- 3 Pendulums: Here it gets really complicated, with chaotic motion that shows no consistent pattern over time. Even small changed in the conditions can produce big changes in the behavior (subject to the overriding conservation of energy)
- 4 or more: Generally unpredictable (subject to the overriding increase of entropy)
Of course, familiar macroscopic examples like this rarely transfer directly to the atomic world of electrons and atoms, where the energy levels are quantised; the energy of a clock pendulum does not appear to be quantised (possibly because we can't measure it accurately enough).
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pendulums (penduli??)
Rarely "pendula" (rather than "penduli") as it is the neuter form of "pendulus"
From the link it seems that only physicists care about "pendula" :)
https://en.wiktionary.org/wiki/pendulum
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I know very little about harmonic oscillators. Can their "energy levels" interact/interfere with one another?
Sorry my lttr "e" has packd up.
Pndulums ar not th bst xampl for sing wav intractions. Wavs travlling ovr th surfac of an ocan intract causing transint paks or standing wavs. This is also sn on lctrical circuits with null points and paks.
All things can b viwd as wavs in QFT wavs intract and produc paks and troughs in spac. Quantum Fluctuations in spac could b th rsult of wav intractions.
I nd a nw kyboard. :)
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Cosmic strings: Gravitation without local curvature by T.M. Helliwell, Am. J. Phys.,55(5), May (1987)
Abstract: http://dx.doi.org/10.1119/1.15145http://dx.doi.org/10.1119/1.15145
Th link dosnt work lik my lttr "e", but from th abstract, thr is a lot of spculation, which is good.
In M thory th strings hav dimnsions and rsonanc, th mmbran howvr appars to hav no dimnsions, doi yoiu hav an opinion on this
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.... This includes the observational predictions of the double imaging of quasars and the truncation of the images of galaxies.
I recall having read, I think it was in Brian Greene’s “The Fabric of the Cosmos” that these strings would be under such enormous tension that this would exactly counter-balance their gravity. If that were the case, would it not eliminate the possibility of gravitational lensing?
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Strings are mathematical models which are fashionable. They do not appear to take into account the entanglement of space time at the plank level, unless it is via the Membrane of M theory. If photons and electrons can be entangled then space time must also be entangled to a certain extent. Einsteins er and epr include wormholes in space time.
Are there any active areas of research that suggest dark matter could be explained away with an additional long range force, transferred via a wormhole, or is this covered with the M-Brane of string theory.
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.... This includes the observational predictions of the double imaging of quasars and the truncation of the images of galaxies.
I recall having read, I think it was in Brian Greene’s “The Fabric of the Cosmos” that these strings would be under such enormous tension that this would exactly counter-balance their gravity. If that were the case, would it not eliminate the possibility of gravitational lensing?
The string if entangled via a wormhole to seperate points in space time might not be stressed.
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The string if entangled via a wormhole to seperate points in space time might not be stressed.
Come back Bill Ockham, all is forgiven! :)
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The string if entangled via a wormhole to seperate points in space time might not be stressed.
Come back Bill Ockham, all is forgiven! :)
Dont stress :) . Kiss works just as well as occams razor, without a priest being involved :)
With a bit of googling my question was along the right lines. With multiple hits on engtanglement EPR ER bridges and wormholes. Here are a couple of random hits https://phys.org/news/2015-05-spacetime-built-quantum-entanglement.html https://en.wikipedia.org/wiki/ER%3DEPR . There are some heavier hits on research gate, all barking up the same tree.
The concept of an infinitely long string is a mathematical convenience, strings are not physical objects as I am sure you realize :) . Wormholes as suggested by that rather clever fellow Einstein, might actually exist and they may be involved in the structure of space time.
A wormhole has no dimensions. The membrane of M-theory that connects both ends of all strings in super string theory has no dimensions. I was asking is the M-Brane of M theory equivalent to a wormhole.
If your string transfers its information via a wormhole in space time, length may not be an issue.
Mixing the holographic principle and wormholes kind of makes sense also when looking at space time and gravity
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https://phys.org/news/2015-05-spacetime-built-quantum-entanglement.html
Thanks. Must try to find a bit of time for that one.
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The membrane of M-theory that connects both ends of all strings in super string theory has no dimensions.
Please clarify this statement.
I read that M-theory has 11 dimensions, and various subspaces of 2 and 5 dimensions.
If true, we would live in a subspace of these 11 dimensions, the dimensions which we can sense stretching for billions of light-years.
See: https://en.wikipedia.org/wiki/M-theory
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Please clarify this statement.
Open strings exist in the early string theories, later string theories use closed strings connected to a membrane or D Brane. This membrane has dimensions but appears at my noddy level of understanding to have no defined physical size. The properties of the particles appear to be governed by the strings. String theories attempting to explain gravity use a membrane or DBrain. https://en.wikipedia.org/wiki/D-brane
String theories of various types have up to 22 dimensions M theory at my last reading was I think 13 dimensions, here is some wiki to clarify. There are lots of string theories out there all attempting to explain different aspects of the universe as i am sure you are aware.
https://en.wikipedia.org/wiki/Superstring_theory