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Dark matter/baryonic matter


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#1 Moontanman

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Posted 14 January 2010 - 07:24 PM

Dark energy is thought to compose 72% of the universe with some sort of matter making up the remaining 28%, 4.6% is thought to be matter, if antimatter is indeed gravitationally repulsive it is conceivable that another 4.6 % is anti-matter, Mirror matter, if it exists, should be the same percentage as matter, 4.6%, with anti-mirror matter making up another 4.6% (anti mirror matter in this scenario would be gravitationally repulsive to both matter and mirror matter but attractive to anti-matter) this makes close to 18% baryonic matter leaving only 10% missing matter, How much of this is hot matter like neutrinos? Could there be another type of baryonic matter, another symmetry breaking type of matter making up the rest leaving no need for non baryonic matter? Another type of baryonic matter/anti-matter pair would be very close to exactly matching what would be needed to make up the rest. Is there another symmetry breaking matter in the wings?

#2 Jay-qu

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Posted 14 January 2010 - 07:57 PM

It is highly unlikely. Dark matter particles are generally called WIMPs for a reason. They are thought to only interact very weakly - through gravity and/or the weak force (plus maybe some Yukawa interactions with the scalar Higgs particles if they exist).

The evidence for the existence of dark matter is more than just the absence of stuff - its effects are felt. Take the stunning example of the bullet cluster: Bullet Cluster - Wikipedia, the free encyclopedia This very strongly implies that there is some mass there that we cant 'see' with light.

#3 Moontanman

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Posted 14 January 2010 - 08:02 PM

Mirror matter fulfills all the perquisites for dark matter as anything else does.

#4 sanctus

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Posted 15 January 2010 - 12:04 PM

Moon, can you send a link to what mirror matter is?

#5 Moontanman

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Posted 15 January 2010 - 12:51 PM

Moon, can you send a link to what mirror matter is?


No problemo

Mirror Matter

Mirror matter - Wikipedia, the free encyclopedia

I have discussed Mirror Matter and possible ways to capture Mirror matter particles with Dr. Foot via e-mail. According to Dr. Foot there should be the same amount of Mirror matter and it's anti-matter counter part as there is matter and anti-matter in the universe.

#6 Jay-qu

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Posted 15 January 2010 - 10:03 PM

No problemo

Mirror Matter

Mirror matter - Wikipedia, the free encyclopedia

I have discussed Mirror Matter and possible ways to capture Mirror matter particles with Dr. Foot via e-mail. According to Dr. Foot there should be the same amount of Mirror matter and it's anti-matter counter part as there is matter and anti-matter in the universe.

And what is his reasoning behind that?

#7 Moontanman

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Posted 15 January 2010 - 10:38 PM

And what is his reasoning behind that?


If I understood what Dr. Foot said, in the same way there should have been the same amount of anti-matter as matter there should have been the same amount of mirror matter and it's anti mirror matter counterpart as there was matter and anti matter.

#8 Jay-qu

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Posted 17 January 2010 - 06:20 PM

The observations of the universe hint that there is more matter than antimatter. Although the exact mechanism that produces this asymmetry is not known, we do know that matter and antimatter are not treated the same by the laws of physics.

Therefore I see no reason to say that you can extend the argument from matter/antimatter to matter/mirrormatter.

#9 Moontanman

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Posted 17 January 2010 - 06:41 PM

The observations of the universe hint that there is more matter than antimatter. Although the exact mechanism that produces this asymmetry is not known, we do know that matter and antimatter are not treated the same by the laws of physics.

Therefore I see no reason to say that you can extend the argument from matter/antimatter to matter/mirrormatter.


I will not mislead you ja-qu and try to say I understand the reason behind the ratios of matter to anti matter but Dr. Foot, both in his e-mails to me and his book which I have, seems to think that the ratios of matter to mirror matter should be one to one. the ratios of anti-matter to mirror anti-matter should also be the same. I do know there is still some disagreement as to whether or not matter and anti-matter are equals or one is grossly more abundant than the other. All i know is that Dr. Foot seems to think the ratios of matter to anti-matter should be the same in mirror matter and anti mirror matter. either they are equal or there is grossly more mirror matter than there is anti mirror matter. If all four are the same then it would account for a big chuck of what we see as dark matter. One more type of matter for some other broken symmetry would account for all the missing matter in the universe.

#10 Jay-qu

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Posted 18 January 2010 - 07:48 AM

I understand that, but I don't believe it.

Another good reason why dark matter cannot be made of mirror matter is that dark matter is weakly interacting with itself. This is evidenced by the shape of dark matter halos around galaxies, which show that it takes a long time for dark matter to come to equilibrium from self interactions.
Link: http://arxiv.org/abs/0911.0422
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#11 Moontanman

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Posted 18 January 2010 - 06:45 PM

I understand that, but I don't believe it.

Another good reason why dark matter cannot be made of mirror matter is that dark matter is weakly interacting with itself. This is evidenced by the shape of dark matter halos around galaxies, which show that it takes a long time for dark matter to come to equilibrium from self interactions.
Link: [0911.0422] Halo Shape and Relic Density Exclusions of Sommerfeld-Enhanced Dark Matter Explanations of Cosmic Ray Excesses


Dr. Foot addresses that in his book if i recall, I'll have to read it again to familiarize my self with it. I know that mirror matter and matter do not easily mix and he said the galactic halo could very well be made of mirror matter stars we cannot see with a smattering of matter stars. Also galaxies we see that seem to be just halos could be mirror matter spirals with matter halos.

#12 Jay-qu

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Posted 19 January 2010 - 08:23 PM

Have a look at this image of the relative sizes of the dark matter halo to the size of the galaxy:
Posted Image

For the Milky way about 50% of the overall mass is in this dark matter halo. That means that the dark matter in the halo is much less dense than in the galaxy. So the natural question to ask is why doesnt it clump together? The answer is that dark matter behaves like a pressureless gas. It only feels the force of gravity. If dark matter interacted via other forces, such as electromagnetism, there would be friction in the gas - collisions between dark matter particles. This would cause it to clump together and form structures like galaxies.

So you see, there is evidence that dark matter does not interact strongly between itself. Whereas mirror matter does interact strongly with itself (just weakly to normal matter), thereby it cannot be the observed dark matter (at least not a significant proportion of it).
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#13 Moontanman

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Posted 19 January 2010 - 09:10 PM

I'll go with that Jay-qu, it makes much sense to me. if I get the chance I'll go over Dr. Foots book again and see if it answers this problem if not he's on his own!