Antimatter And Gravity

[Pmb]

The positron was originally a stable part of matter, co-existing in the nucleus as part of a proton because it is matter.

As Rade explained, this is quite incorrect. Positrons are not found in atomic nuclei as part of a proton. A proton is a proton and does not contain any other particle than quarks. No positrons whatsoever.

[Pmb]

When contemplating this subject is should be kept in mind that which particle is said to be matter and which is said to be antimatter is totally arbitrary. There is no reason why the proton can't be labeled as antimatter and the antiproton labeled as matter. All that makes sense to say is that each particle is the antiparticles of the other. So if one particle displayed antigravity properties and this happened for all antiparticles then this would demonstrate that antimatter does indeed have antigravity properties and that this property determines which particle is the true antiparticle. Otherwise all you've determined is that some particles display antigravity properties while others don't. However I see no reason for any particle to have anti-gravity properties. Especially since there's no reason for it. The term "anti" should not be taken to mean that it has anything to do with any gravitational property.

Edited April 3, 2015 by Pmb

[CraigD]

The positron was originally a stable part of matter, co-existing in the nucleus as part of a proton because it is matter.

As Rade explained, this is quite incorrect. Positrons are not found in atomic nuclei as part of a proton. A proton is a proton and does not contain any other particle than quarks. No positrons whatsoever.

You’re correct, and correct to correct HBond, but his confusion aludes to an interesting quality of particle physics: particles are in a sense more like collections of discrete numbers than like our everyday idea of matter. In a similar sense that an integer (eg: 0) can be considered a ordered collection of natural numbers (eg: 3-2-1), composite or elementary particles can be thought of, and can be transformed into, collections of other particles. For example, in proton (p+) can become a neutron (n) and a W+ boson, the unstable W+ boson becoming a positon (e+) and an electron neutrino (v_e). It’s as if various quantum numbers of the particles, not the particles themselves, are “real”. Even though both protons and neutrons each consist of a probabilistic swirl of 3 quarks and literally innumerable gluons, no positrons in the mix whatever, a proton is, in a sense and via an intermediate boson, a combination of a neutron and a positron.

 

When contemplating this subject is should be kept in mind that which particle is said to be matter and which is said to be antimatter is totally arbitrary. There is no reason why the proton can't be labeled as antimatter and the antiproton labeled as matter. All that makes sense to say is that each particle is the antiparticles of the other.

Which particle of a particle/antiparticle pair are matter and which antimatter is defined by which is most common, as a matter of convention and the historic coincidence that the existence of antimatter particles were theorized and experimentally revealed later than their antiparticles.

 

So if one particle displayed antigravity properties and this happened for all antiparticles then this would demonstrate that antimatter does indeed have antigravity properties and that this property determines which particle is the true antiparticle. Otherwise all you've determined is that some particles display antigravity properties while others don't.

If (contrary to what most particle physicists expect) antimatter particles “have antigravity properties”, that mean they gravitationally repel matter particles, and attract one another. So this hypothesized antigravity isn’t a property of antimatter, but of the interaction of antimatter and matter, as is ordinary gravity.

 

However I see no reason for any particle to have anti-gravity properties. Especially since there's no reason for it. The term "anti" should not be taken to mean that it has anything to do with any gravitational property.

That’s the scientific consensus. However, experiments to actually confirm this are among the most difficult ever to be undertaken, and as most physicists are confident what they will show, don’t attract as much financial and intellectual support as other experiments. They are, encouragingly, being done, by groups like the AEGIS and ALPHA collaborative (mentioned in post #12 and #22), but progress is slow.

[HydrogenBond]

Say, for the sake of argument,  matter and antimatter have gravity and anti-gravity, respectively.

 

Next, we start with an energy field composed of extreme energy photons. These photons split into matter and anti-matter. Because there is an equal split, this will create gravity and antigravity, which will then cancel, the original photon gravity. Now the net gravity goes to zero. 

 

Based on energy conservation, where does the original photon based gravitational potential energy go? 

 

How does the conversion of energy, into matter and anti-matter, disappear the gravity? To maintain energy conservation, the matter and anti-matter would have to contain this extra potential energy, not as net gravity, to account for the potential lost. What is this extra? 

 

As matter and anti-matter combine and annihilate, and photos once again form, gravity returns via  the photons. Does the direction of the reformation of net gravity, via photons, favor matter? In other words,  annihilation turns the "conserved something extra" back to gravity via photons. Does this assymmety favor matter who also have gravity and voids the universe the "extra". 

Edited April 5, 2015 by HydrogenBond

[CraigD]

Say, for the sake of argument, matter and antimatter have gravity and anti-gravity, respectively.

To be simpler and more precise, let’s rephrase this as:

* The mutual force of a body of matter and a body of matter is attractive

* The mutual force of a body of matter and a body of antimatter is repulsive

* The mutual force of a body of antimatter and a body of antimatter is attractive

 

Note that this is hypothetical, and contrary to the scientific consensus, which is:

* The mutual force of a body of matter and a body of matter is attractive

* The mutual force of a body of matter and a body of antimatter is attractive

* The mutual force of a body of antimatter and a body of antimatter is attractive

 

The conventional term for matter that has a mutually repulsive force of gravity with matter is exotic matter, a term that’s used for various other kinds of matter that’s not observed of predicted by mainstream theory. According to conventional theory, antimatter is not exotic matter.

 

Next, we start with an energy field composed of extreme energy photons. These photons split into matter and anti-matter. Because there is an equal split, this will create gravity and antigravity, which will then cancel, the original photon gravity. Now the net gravity goes to zero.

 

Based on energy conservation, where does the original photon based gravitational potential energy go?

That the gravitational potential energy of a small body, such as an electron (e-) or positron (e+) relative to a large primary body, such as a planet or star “cancels out” if it is split into to bodies, one of which is attracted by the primary, the other repelled, in incorrect. To understand why, we need to look at what the concept of GPE actually is.

 

I’ll use classical mechanics, GPE is easier to explain using it than the more accurate General Relativity. For purposes like this discussion CM gives nearly identical results as GR, so this approximation is OK.

 

As with all energy, GPE represents the potential of a system to perform mechanical work. GPE represents the work that can be performed by a system when bodies in it change position in a gravitational field. The simplest system consists of a single or a few small test bodies and a large primary body, so I’ll use that here.

 

The formula for GPE is [math]E = \frac{k}{r}[/math], where for attractive gravity, [math]k = -G m_0 m_1[/math], [math]r[/math] is the distance between the centers of mass of the test and primary body, [math]G[/math] is the gravitational constant, and [math]m_0[/math] and [math]m_1[/math] are the mass of the primary and test body. For repulsive gravity the sign of [math]k[/math] is changed, [math]k = G m_0 m_1[/math].

 

GPE is used to calculate the work that can be performed by a system when [math]r[/math] changes by subtracting the GPE for the initial [math]r_0[/math] from that for the end [math]r_0[/math], that is

[math]E = \frac{k}{r_1} - \frac{k}{r_0}[/math]

 

The differences, then, between GPE for attractive and repulsive gravity, then, are that:

• for attractive gravity, it’s always negative,

  for repulsive, always positive;

• for attractive gravity, increasing [math]r[/math] (“raising”) the test body increates GPE,

  for repulsive, decreasing [math]r[/math] (“lowering”) the test body increates GPE

So, considering the original question

Based on energy conservation, where does the original photon based gravitational potential energy go?

We can see that the GPE relative to an unspecified primary of the electron and positron that the photon (v) splits into while when added together give zero, shouldn’t be added together, because the potential of the 2 particles to perform work when their distance to the primary changes is the same as the photon’s – it’s just that, the electron’s GPE decreases as it “falls” toward the primary, while the positron’s decreases as it falls away from the primary.

 

It’s important to note that, because electrons and positrons are charged and have low masses, and the gravitation force exerted on bodies due to their mass is much, much (about 10²⁵ times) weaker than that of the force exerted on them due to their charge, the effect of gravity in the example is negligible. The behavior of an electron and positron if they gravitationally repel one another (a much larger primary isn’t part of this system) is only minutely different than if they attract one another, because the force of their attraction due to their different charges is so much stronger than the force of gravity.

 

Does this assymmety favor matter who also have gravity and voids the universe the "extra"[?]

Though I hope I’ve explained the lack of an asymmetry related to GPE if matter and antimatter are gravitationally repulsive, this hints at some profound cosmological question:

• Why, as the simplest theories suggest that equal amounts of matter and antimatter were created early in the history of the universe, didn’t it all mutually annihilate, leaving nothing but photons?
• Why is there so much more matter than antimatter?
• If matter and antimatter gravitationally repel one another, could large bodies like galaxies, which have practically zero net charge and large masses, exist made of antimatter, and gravitationally repel galaxies and small intergalactic bodies (eg: dust and gas) made of matter?

[HydrogenBond]

......

 

Though I hope I’ve explained the lack of an asymmetry related to GPE if matter and antimatter are gravitationally repulsive, this hints at some profound cosmological question:

• Why, as the simplest theories suggest that equal amounts of matter and antimatter were created early in the history of the universe, didn’t it all mutually annihilate, leaving nothing but photons?
• Why is there so much more matter than antimatter?
• If matter and antimatter gravitationally repel one another, could large bodies like galaxies, which have practically zero net charge and large masses, exist made of antimatter, and gravitationally repel galaxies and small intergalactic bodies (eg: dust and gas) made of matter?

 

 

Photons generate gravity and therefore the formation of photons from the annihilation of matter and anti-matter, will shift the equilibrium toward matter. In other words, as photons form, due to annihilation, the matter becomes selectively attracted because of the gravity of the energy. The gravity of the energy, selectively attracts matter until there is a discontinuity. 

 

Since the extracted matter is not only under its own gravity, but also under the gravity of energy, the composite gravity of energy and matter, will become increasingly stronger than the anti-gravity of the remaining anti-matter.  

 

I would guess the stronger composite gravity, being applied to the matter, does something to the matter, that the anti-matter does not see. Our matter universe suggests the composite gravity adds stability, which gets stronger and stronger.

 

I can see the stability of the matter via the composite gravity, inducing elementary particle transitions that stabilize matter against anti-matter; not exactly opposite anymore. Since anti-gravity is still in effect, we will still get the repulsion of antigravity; inflation, while anti matter, by losing more and more antigravity to annihilation, begins to feel gravity and changes? 

Edited April 7, 2015 by HydrogenBond

[pgrmdave]

Photons generate gravity

I'm gonna need a source on this, it sounds wrong but I'm not an expert physicist.

[HydrogenBond]

I think energy impacts space-time via GR. 

[CraigD]

Photons generate gravity

I'm gonna need a source on this, it sounds wrong but I'm not an expert physicist.

I’ve only had a few undergraduate hours of modern physics, so don’t know General Relativity soundly, but my understanding is that “photons generate gravity” is a valid translation of its formalism into plain language, though incomplete enough to risk confusion.

 

Core ideas of GR are that of mass-energy equivalence, or, more completely, the energy-momentum relation, [math]E^2 = m^2 c^4 +p c^2[/math], and a relationship of energy to spacetime that is approximated by the relationship of mass to gravitational force in Newtonian gravity.

 

The energy-momentum relation gives zero-mass particles like photons nonzero energy because they always have a nonzero momentum (p), and particles with nonzero mass energy regardless of their momentum because they have nonzero mass (m).

 

So a photon at a given point in space with an energy equivalent to a massive particle at rest has, for the instant, the same gravitational effect that the massive particles would at that point.

 

The obvious and most critical difference between the gravitational effect of photons and nonzero mass particles is that photons always move at the speed of light ( c ) while nonzero mass particles always move at less than c, often at close to zero. Thus, although in principle a star or planet-like volume of space could contain a number of photons energy and gravitationally equivalent to the mass of a planet or star, they wouldn’t stay in that volume very long, so we don’t see solar systems consisting of bodies made of photons. The exception to this is that, if a sufficient number of photons of sufficiently high energy are concentrated is a sufficiently small volume, they can be a kind of black hole known as a kugelblitz. Though theoretically possible, no kugelblitz has actually been observed.

[HydrogenBond]

If we assume the singularity of the BB, which is part of main stream science, you begin to approximate the dense conditions of the black hole; mother of all singularities. If we have matter and anti-matter forming from photons, and then recombining to form energy, the gravity due to the energy will add to gravity due to matter, causing gravity to exceed the anti-gravity, due to anti-matter. 

 

This transition would be consistent with an inflation period, where the amount of particles doubles (or more) as photons split into matter and anti-matter and gravity and anti-gravity cancel; needs room while lacking resistance. This is short lived as energy quickly reforms and begins to add to the gravity of the matter, causing a potential that favors matter. This puts the brakes on the inflation period. 

 

The fact we don't see a high percent of left over anti-matter, existing as pockets in the universe; extraction and phase separation, suggests a phase change of the anti-matter into matter, due to the extreme gravity. Gravity causes pressure, and the pressure cause phase changes. Matter and anti-matter work from the same set of quarks. 

 

I always thought that matter and antimatter were not exactly equal and opposite, favoring matter. Instead of this being innate to modern matter, it appears to be more connected to energy and gravity. If you assume a unified model, then gravity and matter are like two peas in a pod. Extreme energy and matter gravity will favor matter peas; for a stable equilibrium. 

Edited April 13, 2015 by HydrogenBond