Firstly:
Mjolnir wrote:As for dark matter, antimatter isn't dark, it interacts quite happily through electromagnetic forces. Dark matter is also attractive (rather at odds with the idea that antimatter and matter repel), and has an attractive effect several times greater than the visible matter.
For a moment I couldn't figure out why you even brought this up, then I looked at the topic title. Oops, I meant to write dark
energy. Sorry about the typo.
Mjolnir wrote:Antimatter particles mirror their matter counterparts in charge and parity, or time. Parity is basically handedness or chirality....an charge-reversing mirror would make an proton look like an antiproton, or like a time reversed proton.
I'd heard of that 'theory' (isn't it actually a simple and straightforward interpretation of the relevant Venn diagram(s), actually?), and was under the impression that it was generally accepted. Though I do question your "mirror their matter counterparts ... parity" wording, since that would imply that the parity itself could be mirrored (consider: one particle looks like it's counterpart through the mirror, the other
looks like itself though the mirror: their
parity/chirality is mirrored, leading to bizarre results which I doubt you intended to imply).
What would the set of particles including protons, anti-protons, and any theoretical others (e.g. the various suggested 'negative matter' protons) be? The best I can think of is 'meta-protons', but I don't recall hearing of a 'meta-symmetry' postulate/theory, so I assume that's not the right name.
Mjolnir wrote:(One model for electrons has exactly one electron in the universe, pair production and annihilation events actually being it reversing direction through time.)
That road could easily take you down the path of only having one of EACH particle, and from there it's seemingly inevitable that you work your way down to the idea of there only being one (or perhaps two, if you feel like being generous to yourself) Planck units of energy (perhaps on a 4-sphere, with the extra axis obviously being time). This, in turn, leads you to things like particular FTL travel theories that would probably be utterly un-navigatable even if possible, which leads us to what I suspect such particle models probably are: useless.
Mjolnir wrote:As for the suggestion that antimatter and matter repel...GR does not support repulsive gravity. Space is curved by mass-energy, and due to simple geometry, objects in free motion curve toward an area of greater curvature, regardless of the "sign" of that curvature...what matters is the path lengths being longer through that curved area of space.
This particular theorist seems to disagree, but I'm hardly qualified to judge. Still, you're basically saying that his claim would require anti-matter to produce... 'inverse curvature' (or would 'reciprocal' be better in this case?), essentially non-Euclidean curvature effects, correct? And if simply reversing the ( energy * mass ) sign of a particle was enough to produce such an effect, we would presumably see the same effect with electrons, correct?
Mjolnir wrote:In any case, antimatter has positive mass-energy, or matter-antimatter annihilation would simply make particles disappear due to their net energy being zero. Negative-energy matter has been speculated about (as something needed for wormholes or diametric drives to work, for example), but it'd be something completely different from antimatter.
I was extrapolating on the thought 'perhaps they're supposed to collapse due to gravity affecting their structures'. Is it supposed to be related to boson-number or the like instead?
Mjolnir wrote:I've never seen any explanation for why antimatter might have negative gravity or why matter and antimatter would gravitationally repel.
The first, I believe, comes from the assumption that if you:
1) have a particle whose attributes can be tied to three axes, and
2) the product of the three axes cannot vary (or else it becomes a different particle, I assume), and
3) you can change the sign of one of these axes ('electrical charge', for example), then:
4) that means that for such a sign-change to work, you must also change the sign of another axis.
Science currently seems to say that second axis is 'time', this scientist seems to be suggesting 'gravity' instead. Which does, itself, at least
imply to me the requirement that gravitons (theoretical though they be) are NOT their own anti-particle in order for this to work.
The gravitational repellance of matter and anti-matter would be a straight-forward assumption, if you already assume both (4), and that the 'second axis' is gravity.
Mjolnir wrote:This would just switch the matter-antimatter imbalance around, while raising the questions of why we can't see the huge quantities of antimatter around us and in those cosmic voids,
Indeed, I even commented on this already. Though I feel that the question 'how do we know there aren't galaxies made of anti-matter
that we can already see, and have misidentified' is relevant
regardless of anti-matter's 'gravitational sign'.
Mjolnir wrote:Another big issue with antimatter and matter repelling each other...photons are their own antiparticle. In gravity lensing observations, they quite clearly are not being repelled from matter half the time. Star images get deflected, they don't split into separate light and antilight images or smear out in radial lines as individual photons randomly switch between acting as photons and antiphotons.
If you're willing to accept the possibly non-Euclidean implications of 'anti-matter emits anti-gravity' in the first place, then I don't think MORE weird behavior is going to slow you down.