Curvature caused by Photons too ?

[Widdekind]

As SwansonT said the experiments on antihydrogen at cern indicate this is not the case. The anti-hydrogen (ie anti-matter that was not electrically charged) created at CERN had to be maintained within a huge magnetic field - if matter repelled anti-matter it could have been easily constrained within any system made of normal matter. the link to the nature article that describes the containment of anti-hydrogen is here. Anti-matter is opposite charge - not opposite mass.

 

Thanks for the clarification (Swansont), and link (Imatfaal). Would Imatfaal please quote the article? I understand, that anti-hydrogen would be neutrally charged, and, so, would interact, only magnetically, and gravitationally. And, if anti-hydrogen had negative 'anti-mass', it would experience a +g 'anti-gravitational' acceleration, of ~10 m/s/s, upwards. Otherwise, it would fall earth-wards, accelerating at -g. These accelerations, and forces, are equal (if opposite). So, why would the counter-acting magnetic forces, required to offset them, be so vastly different ?

[alpha2cen]

Thanks for the clarification (Swansont), and link (Imatfaal). Would Imatfaal please quote the article? I understand, that anti-hydrogen would be neutrally charged, and, so, would interact, only magnetically, and gravitationally. And, if anti-hydrogen had negative 'anti-mass', it would experience a +g 'anti-gravitational' acceleration, of ~10 m/s/s, upwards. Otherwise, it would fall earth-wards, accelerating at -g. These accelerations, and forces, are equal (if opposite). So, why would the counter-acting magnetic forces, required to offset them, be so vastly different ?

 

Gravity is related to energy related mass.

vacuum+energy+ P---------------->2P +P^-

= energy---------->P + P^-

From E=mC² equation

energy = (m(P) +m(P^-))C²

New generated P and P^- have same space-time curvature.

So antimatter has, my guessing, same gravity direction like matter.

But magnetic related force is opposite.

Because at the center of the anti-hydrogen has minus charge and it's outside orbit positron has plus charge.

[Widdekind]

If matter & antimatter 'bulged' in opposite directions, then local matter would be 'anti-matter-like', to remote matter, 'on the other side of space':

 

 

It's my understanding, that anti-matter is matter that has been 'scooped up, like a pancake off of a griddle, and plopped back down', onto, and into, spacetime. Such an effect, amounting to a '180 degrees hyper-spatial rotation', would 'reverse everything', accounting for CPT effect. 'Looking at the pictures', anti-matter 'should', then, bulge 'in the opposite direction', as normal matter (along with every other physical 'reversal'). Such an argument, though, does amount, to 'GR in pretty pictures'.

[alpha2cen]

If antimatter had anti-gravity, matter-antimatter annihilation reaction could not occur easily at the early Universe.

The anti-matter have been separated from matter, and we can see the antimatter easily through the optical telescope.

[Widdekind]

If matter & anti-matter both have positive mass, then energy must gravitate. For, imagine one mass of matter, 'sagging down' on the 'rubber sheet' of spacetime, meeting another mass of anti-matter, also 'sagging down'. At the moment the matter meets the anti-matter, they 'combust' into raw energy. If, the moment before they combust, spacetime is 'sagging down', then the moment of their combustion, when all the resulting released raw energy is still packed into a tight bundle, spacetime must still be 'sagging down', unless spacetime can instantaneously 'jump' back to its equilibrium position. If so, energy gravitates, too -- even though mass is some 'stable form' of energy, that can remain perpetually localized, whereas raw energy will try to diffuse & spread outwards.

 

Moreover, most of the mass, in all of the cosmos, is intra-nuclear 'glue'. For, electrons mass merely ~1/2000^th that of their nucleon counterparts. And, in those nucleons, the three 'bare naked' quarks, combined, merely mass ~10 MeV, out of the ~940 MeV nucleon mass-energy. Thus, roughly 930/940^ths [math]\approx[/math] 99% of all the mass, in all of the matter, inside this spacetime, is the 'glue' that 'dresses' the bare quarks. And glue, representing inter-quark gluon bonds, is made of massless gluons -- which, yet, gravitate strongly. Such suggests, equally strongly, that energy gravitates, not merely matter.

 

Conversely, if anti-matter had anti-mass, so that it bulged in the 'opposite direction' from matter -- 'floating up' instead of 'sagging down' -- then, when the two combined (as per OP), they would annihilate into flat spacetime, which yet contained all the energy released from that explosion. If, then, large amounts of energy can exist, in flat spacetime, then energy must not cause curvature in spacetime -- to wit, energy would not gravitate. The gravitation, or non-gravitation, of energy, determines which picture is correct. And, again, that gluons are massless, yet energetic, and highly gravitationally interactive, seemingly suggests, that raw energy does gravitate.

[swansont]

It's my understanding, that anti-matter is matter that has been 'scooped up, like a pancake off of a griddle, and plopped back down', onto, and into, spacetime. Such an effect, amounting to a '180 degrees hyper-spatial rotation', would 'reverse everything', accounting for CPT effect. 'Looking at the pictures', anti-matter 'should', then, bulge 'in the opposite direction', as normal matter (along with every other physical 'reversal'). Such an argument, though, does amount, to 'GR in pretty pictures'.

 

Where does mass enter into CPT symmetry?

[alpha2cen]

If matter & anti-matter both have positive mass, then energy must gravitate. For, imagine one mass of matter, 'sagging down' on the 'rubber sheet' of spacetime, meeting another mass of anti-matter, also 'sagging down'. At the moment the matter meets the anti-matter, they 'combust' into raw energy. If, the moment before they combust, spacetime is 'sagging down', then the moment of their combustion, when all the resulting released raw energy is still packed into a tight bundle, spacetime must still be 'sagging down', unless spacetime can instantaneously 'jump' back to its equilibrium position. If so, energy gravitates, too -- even though mass is some 'stable form' of energy, that can remain perpetually localized, whereas raw energy will try to diffuse & spread outwards.

 

 

That problem had been discussed before.

Have a look #28

http://www.scienceforums.net/topic/54114-can-we-make-minus-mass/page__st__20

 

and #19

http://www.scienceforums.net/topic/53807-curvature-caused-by-photons-too/

 

I stated the mass "primal mass".

But the concept has not been authorized yet.

[Widdekind]

Seemingly the simplest statement, is that there are two 'flavors' of matter -- perhaps, thinking of matter as like little 'vortices', in 2D Flatland, matter comes in 'right-handed cyclonic' & 'left-handed anti-cyclonic' varieties, 'looking down' from hyperspace. Whatever be the case, there are two 'varieties' of matter, and they are equivalent. Thus, although 'ideal mathematical equations' say the universe 'should' have started with equal parts M/AM, reality, in fact of practice, was somewhat 'sloppy'. So, there happened to be a bit more of one 'flavor' than the other. And, whichever one it was, we would, obviously, having evolved out of the stuff billions of years later, call that 'normal matter'. In sum, it could have 'gone either way', but, by Anthropic Principle, whichever one 'won out', we'd be bound to dub the same 'normal' matter. By such statements, M/AM doesn't seem so 'mysterious', just typical numerical discrepancies, between math ideal (50-50 split) and actual fact (50.1-49.9%).

[Widdekind]

http://www.physorg.com/news/2011-04-antimatter-gravity-universe-expansion.html

 

the current formulation of general relativity predicts, that matter and antimatter are both self-attractive; yet, matter and antimatter mutually repel each other...

 

there is more than just mass involved in gravity. In this case, time and parity are involved...all physical laws have CPT (charge, parity, and time) symmetry. CPT symmetry means that, in order to transform a physical system of matter into an equivalent anti-matter system (or vice versa) described by the same physical laws, not only must particles be replaced with corresponding anti-particles (C operation), but an additional PT transformation is also needed.

 

From this perspective, antimatter can be viewed as normal matter that has undergone a complete CPT transformation, in which its charge, parity and time are all reversed. Even though the charge component does not affect gravity, parity and time affect gravity by reversing its sign. So although antimatter has positive mass, it can be thought of as having negative gravitational mass, since the gravitational charge in the equation of motion of general relativity is not simply the mass, but includes a factor that is PT-sensitive and yields the change of sign... CPT symmetry means that antimatter basically exists in an inverted space-time (the P operation inverts space, and the T operation inverts time).

If anti-matter has anti-mass, then anti-matter would plausibly "curve space the opposite way" to matter. And if so, then the "combusting" combination, of anti-matter & matter, would plausibly "cancel out the space curvatures", leaving behind only flat space, as per Rudy Rucker's proposal, per OP.

 

If so, then only rest-mass would plausibly gravitate; and, energy would plausibly not gravitate. If so, then the "destructive combustion" of large amounts of matter, into energy, via nuclear processes, over the age of our universe, would plausibly have reduced the gravitating matter density, inside our space-time fabric, i.e. by a factor of ~e<Z> (fusion efficiency x cosmic metal mass fraction), i.e. ~(0.007)x(0.007)=5e-5.

 

If so, how would a declining matter density affect the evolution, of a FRW cosmological model? For example, if our universe was "born" closed, with a slight over-critical-density; and if our universe then started "losing matter", via fusion in stars; then, would not our universe begin to "balloon outward", cp. R_curvature~D_H/sqrt( over-density ). Is that what to which the article is referring, when suggesting, that the proposed anti-gravity of anti-matter could account for the "extra expansion" of space-time, presently attributed to 'Dark Energy' ?? For example, if it so happened, that our universe was "born" with an over-critical-density of ~5e-5; then, natural mass-destroying fusion in stars would have expanded our universe, from "closed", to "flat-and-open", i.e. the expansion of the space-time fabric would look like it was "accelerating", yes ??

[Widdekind]

If energy does not gravitate, then spontaneous, exo-thermic, energy-releasing, mass-destroying reactions (e.g. chemical bonding, nuclear fusing) "flatten" the fabric of space-time. Would that then imply, that space-time "hates" being curved, and "wants" to flatten out, and "pressures" massive particles to convert mass-to-energy ??

 

If so, then the "desire" of space-time fabric to "flatten" could possibly also account, for the spreading of wave-functions (curvature is caused by density, decreasing density, via WF spreading, flattens the fabric of space-time).

Edited December 29, 2011 by Widdekind

[imatfaal]

As Villata explains, the current formulation of general relativity predicts that matter and antimatter are both self-attractive, yet matter and antimatter mutually repel each other.

 

I do not agree with this line from the article you have quoted - actually doing the maths is beyond me, but I am sure that I have read that matter and antimatter would be gravitationally attractive, and the simplified equations and thought experiments on the subject bear out this side.

[J.C.MacSwell]

Then why doesn't light warp the fabric of space time? And how do you know that? What about that graviton theory? Why don't things warp the fabric of space more as they gain more energy instead of mass? Why would black holes form from gamma-ray bursts? How come an atom of hydrogen with the temperature equal to 72 degrees F has the same gravity as a hydrogen atom with a temperature of -275 degrees F? I don't see temperature anywhere when calculating the gravitational effects of an atom?

 

Unless are you trying to say something about density since generally objects with more energy are less dense?

 

Or are you assuming the Gauge Boson theory is true (which would make sense, but then there would be no fabric of space that's being warped)?

 

I'm not trying to say your wrong, it's just that these are the questions I have that arise from your statement.

 

An atom of hydrogen would not have a defined temperature. If you heat something up the mass increases and that mass would be considered in any gravitational effect calculation.

Edited December 29, 2011 by J.C.MacSwell

[Widdekind]

I do not agree with this line from the article you have quoted - actually doing the maths is beyond me, but I am sure that I have read that matter and antimatter would be gravitationally attractive, and the simplified equations and thought experiments on the subject bear out this side.

 

Indeed, matter attracts matter, and anti-matter attracts anti-matter. However, the former may repel from the latter.

 

If anti-matter anti-gravitated, w.r.t. normal matter, then you could "evaporate" black holes, by pumping them full of anti-matter.

 

Also, naively, if our cosmos is closed, then our space-time fabric has a "curvature preference", and is not flat. And, naively, such a "curvature preference" sounds similar, to the "matter preference", over anti-matter, if the two "curve in opposite directions". For, matter would curve space, in the "same way" as space was already curved, like a bump, on a ball. Whereas anti-matter would curve space, "the wrong way", like trying to put a dent, into a ball.

 

And, the degree of matter-over-anti-matter preference, is measured by the baryon-to-photon ratio (since the photons were generated, by the complete annihilation, of all of the anti-matter). So, perhaps the implication is, that the baryon-to-photon ratio, reflects the degree of global curvature, at the epoch of nucleo-synthesis, i.e. if NS had occurred, when the "ball" of space-time was small, with a small radius-of-curvature, that large curvature would have brooked hardly any anti-matter to have formed "the wrong way", so few photons, from annihilations, would have been generated, and the B2P ratio would have been higher, et vice versa ?

[Widdekind]

Where does mass enter into CPT symmetry?

 

According to the article:

 

all physical laws have CPT (charge, parity, and time) symmetry. CPT symmetry means that, in order to transform a physical system of matter into an equivalent antimatter system (or vice versa) described by the same physical laws, not only must particles be replaced with corresponding antiparticles (C operation), but an additional PT transformation is also needed.

 

From this perspective, antimatter can be viewed as normal matter that has undergone a complete CPT transformation, in which its charge, parity and time are all reversed. Even though the charge component does not affect gravity, parity and time affect gravity by reversing its sign. So although antimatter has positive mass, it can be thought of as having negative gravitational mass, since the gravitational charge in the equation of motion of general relativity is not simply the mass, but includes a factor that is PT-sensitive and yields the change of sign.

 

As Villata explains, CPT symmetry means that antimatter basically exists in an inverted spacetime (the P operation inverts space, and the T operation inverts time)

What is the "factor that is PT-sensitive and yields the change of sign" ?? That factor would derive from the S.E.T., on the RHS of the GR equation ??

 

In Feynmann diagrams, anti-particles are always pictured "going backwards through time", is that T ??

 

 

---

 

I understand, that the Christoffel symbols are derived, from the metric tensor:

 

[math]\Gamma \leftarrow g[/math]

and, that the Einstein tensor is derived, from the Christoffel symbols:

 

[math]R \leftarrow \Gamma[/math]

and, that GR equates the ET, to the SET:

 

[math]R \approx T[/math]

Now, from a (3+1)D space-time perspective, PT 'merely' represents the inversion, of all space-and-time coordinates, i.e. [math]\forall \mu \in \{ x,y,z;t \}[/math]:

 

[math]x_{\mu} \rightarrow -x_{\mu}[/math]

and,

 

[math]\partial_{\mu} \rightarrow - \partial_{\mu}[/math]

Naively, since the Christoffel symbols involve an odd number of those derivatives (n=1),

 

[math]\Gamma \rightarrow -\Gamma[/math]

Naively, the 'equation of motion' in GR, for objects in free-fall, is crudely-and-rudely expressed, as:

 

[math]0 = \frac{d^2 \vec{x}}{dt^2} + \Gamma \frac{d \vec{x}}{dt} \frac{d \vec{x}}{dt}[/math]

Naively, if so, then both terms, of the 'EoM', involve an odd number of components (n=3), each of which individually inverts, under PT, so that:

 

[math]\left( 0 = \frac{d^2 \vec{x}}{dt^2} + \Gamma \frac{d \vec{x}}{dt} \frac{d \vec{x}}{dt}\right) \; \longrightarrow \; \left( 0 = -\left(\frac{d^2 \vec{x}}{dt^2} + \Gamma \frac{d \vec{x}}{dt} \frac{d \vec{x}}{dt}\right)\right)[/math]

Naively, I have come to conclude, that PT does not invert the EoM; and come into conflict, with Prof. Villata, per said cited article.

 

Naively, moreover, the ET involves products, of even numbers, of those CSs & Ds (n=2), so that:

 

[math]R \rightarrow R[/math]

Naively, therefore, PT leaves the ET invariant. What about the SET? Naively, the SET has components, which are products, of even numbers of (time) derivatives (n=0,2), so that [math]T \rightarrow T[/math]. Naively, PT leaves the entire GR 'master equation' invariant:

 

[math]\left( R \approx T \right) \; \longrightarrow \; \left( R \approx T \right)[/math]

Naively, if all physical laws are CPT invariant, and if GR is PT invariant, then GR is C invariant. Naively, if so, then antimatter gravitates like matter, "no matter how you look at it", i.e. GR is symmetric w.r.t. "CPT by assumption, PT by proof, C by implication".

 

Why does Prof. Villata say otherwise ??

Edited January 10, 2012 by Widdekind

[swansont]

According to the article:

 

That's an hypothesis. Not yet established as valid.

[Andeh]

That sounds wrong to me. They both have mass, and so would induce the same curvature. Photons would, too.

maybe he's not talking about mass curvature, but the theorized curvature that charge causes on 5-d space.

[questionposter]

I keep seeing around these forums and from scientists like Niel DeGrasse that photons curve the fabric of space. How is that? How do photons curve the fabric of space?

Edited January 15, 2012 by questionposter

[Widdekind]

I keep seeing around these forums and from scientists like Niel DeGrasse that photons curve the fabric of space. How is that? How do photons curve the fabric of space?

 

I understand, that according to GR theory, all mass-and-energy curves the fabric of space-time, i.e. "the fabric of space-time perceives all matter & energy in the same way", or "everything is effectively a photon to space-time".

[questionposter]

I understand, that according to GR theory, all mass-and-energy curves the fabric of space-time, i.e. "the fabric of space-time perceives all matter & energy in the same way", or "everything is effectively a photon to space-time".

 

So energy or photons distorts the fabric of space even though they doesn't have mass? What's the point of having mass then? Mass then? Doesn't that pretty much disprove the existence of mass if photons can distort the fabric of space without some sort of "higg's boson" or "mass causing particle"? How could force carriers themselves emit force carrier particles?

Edited January 16, 2012 by questionposter

[IM Egdall]

So energy or photons distorts the fabric of space even though they doesn't have mass? What's the point of having mass then? Mass then? Doesn't that pretty much disprove the existence of mass if photons can distort the fabric of space without some sort of "higg's boson" or "mass causing particle"? How could force carriers themselves emit force carrier particles?

 

It all comes from E=mc^2. Mass and energy are equivalent. They both produce the same physical effects. Such as producing gravity (spacetime curvature).

 

So massless particles such as photons are a source of spacetime curvature -- they distort, bend, warp space and time just like particles with mass do. In addition, photons have momentum and inertia, just like particles with mass do.

[swansont]

So energy or photons distorts the fabric of space even though they doesn't have mass? What's the point of having mass then? Mass then? Doesn't that pretty much disprove the existence of mass if photons can distort the fabric of space without some sort of "higg's boson" or "mass causing particle"? How could force carriers themselves emit force carrier particles?

 

In GR, gravity is not a force. GR is also quite separate from the standard model, so the Higgs really doesn't come into play.

[IM Egdall]

As I understand it, if not for the Higgs field, all particles would travel at the speed of light. Most particles, however, do interact with the Higgs, so gain mass (like electrons and quarks). And (I'm not totally sure of this), the faster these particles go, the more they interact with the Higgs field. So they become more and more massive and cannot achieve the speed of light.

 

Some particles (photons, gluons, and the yet to be detected gravitons) do not interact wth the Higgs field, so are massless and travel at the speed of light.

Edited January 17, 2012 by IM Egdall

[questionposter]

..

Edited January 18, 2012 by questionposter

[Widdekind]

How could force carriers themselves emit force carrier particles?

 

gluons are the force-carriers, of the Strong interaction. gluons carry Strong "color" charge, and so can generate more, of the very field, that they mediate. (imagine if photons carried electric charge, then they, too, could generate EM fields, even as they propagated them.)

[questionposter]

So in the standard model, how do photons cause gravity then? They don't interact with the Higg's field, yet scientists are still planning on building accelerators that use the gravity of very very high energy photon lasers to accelerate particles.

Edited January 19, 2012 by questionposter