Dark Gravity discussion

[PB666]

The xenon detector suggests that it does not interact with matter at all, no observed interactions.

I was thinking about this problem. In order to know what DM is we first need to know what matter is, the discussion as Tyson points out is not visible matter versus invisible matter, but visible sources of gravity versus invisible sources. Here in lies the principle problem, and it not just dark gravity, visible sources of gravity as mentioned here before is not perfect.

If we talk about the ability of matter-energy to warp space-time, its defined by G, the universal gravitational constant. But in fact we have never defined G, we have defined GM for certain objects, one being earth

GM_earth = G * (SumM[Visible] + SumM[Invisible]) = 3.98600442 ×10¹⁴.(Note this is three decimal places better than G). If we state that DM does not interact with matter strictly then I can take a cubic centimeter of iron, pull it away from its resting source, and it should not carry residual or mass dependent accumulations of dark matter, and therefore I can measure the density of iron, water or whatever. Surface experiments have confirmed that G is accurate minimally to  6 decimal places. We can therefore estimate density of earth as 5.513 g/cm³. We can rewrite the equation above, converting density to KMS system. 

GM_earth = G * Volume  (D[Visible] + D[Invisible]) = 3.98600442 ×10¹⁴

In doing this we would find that if D invisible is >5X visible then the Earth is so constructed of water. Obviously it is not, the earth has a density above that of silicon dioxide. It cannot be absolutely said that there is no Dark density to the earth, but it can be said that the density of dark matter in the earth under represents the dark matter:visible matter ratio of the universe. And that suffices, unless, we have really miscalculated G. Now we know that GM is pretty good, otherwise GPS systems would not work.

Mantle appears to be made of olivine. "The project, which is running under the auspices of the International Ocean Discovery Program (IODP), would give scientists access ultimately to fresh, unaltered peridotite - the rock, rich in olivine minerals, that, because of the size of the mantle, makes up the bulk material of the planet's interior. - http://www.bbc.com/news/science-environment-34967750"

Olivine's (Fe,Mg)₂SiO₄ specific gravity is 3.3. http://www.minerals.net/mineral/olivine.aspx. Below this is the lower mantle . . .it appears to be made of more dense (Fe,Mg)₂SiO₃having specific gravity up to 4.03 (for CaTi0₃)

There is a deeper problem than this. Suppose we had a model where a dark matter strand became the nucleating body of the earth. OK and so visible matter accumulated around the nucleus. Here's the problem, since earth originally formed in collided with another mars like planet (lepton/photon/hadron interactions defining the collision), the dark matter nucleus would be oblivious to these interactions, both objects would have exherted dV on each other, but not the dark matter, which would have continued on in its orbit, deflecting strongly as it passed by the other bodies nucleus. IOW the collision produced intense momentary inertial references frames for both objects; however the dark matter remained in a non-inertial reference frame and continued about a unknown orbit about the sun.

But lets say for some magical reason it didn't, the nuclei would be now circulating in the earth (since the moon was formed from earths surface material it lost its nucleus). Why would it be circulating,

1. The Thera/preEarth orbit is different from the earth moon orbit about the sun. The combination resulted in an evolving center of gravity relative to both earth and moons center.
2. The dynamo at the center of the earth creates a magnetic field, this is created by the moon/tidal effects. For every reaction there is an equal and opposite reaction.
3. Because the moon formed from earths surface material and because it is being accelerating by earths tides that position would not be the earth/moon cog, it would be offset and/or have a different period.

Therefore this fictitious nucleus would have a motion relative to the earth. If such a massive nucleus had a motion relative to the earth then gravity at any position would not be constant and would not be predictable with the positions of the sun or moon. In fact if D_dark was and significant fraction of D_total then we would see surface gravitational anomalies everywhere, all the time. GPS would not work.

Therefore a conclusion is that there is no significant dark matter in the earth or that it lacks any cohesion within the earth. Even if dark matter lacked cohesion, the Earth/Thera collision would have resulted in the decoupling of dark matter from the earth, and it would be detected in orbit about the sun, or otherwise thrown from the earths orbit by long term interaction with the earth and jupiter. Occam's razor applies here, unlikely that dark matter was the nucleus for earths accretion in any significant degree. This does not rule out the possibility that rapidly traveling intersecting threads of dark matter brought dust particles together into larger clumps, just that the clumps would not bind the threads. So here is the basic problem, if dark matter lacks cohesion, suppose I very carefully carve out a cube of rock holding it in place as I carved it, then I placed a scale under the cube as a cut the last amounts of rock holding it in place, using a telescoping feet on the balance that was attached from chains above I would weigh the cube for rock, it would weigh more. If I then took the rock out and carried it to say a high peak or measured its momentum in space, it would show less mass. Obviously we are not seeing these types of anomalies either.

The same logic can be applied to just about every body of the solar system.

So my conclusion is that either some fundamental physics is way wrong or that dark matter spends a minuscule amount of time in our solar system. If Dark Matter was a major constituent of the Oort cloud (IOW that 4/5ths of the systems missing dark matter was in the Oort cloud) the keplarian motion of our solar system would not work (In fact we would not have the Keplarian laws of motion). So this pretty leaves the Dark gravity stuff in deep interstellar space or in planes above and below the galactic plane.

These are my ideas, I would like to hear critiques or counter arguments.

 

 

 

 

 

Edited December 2, 2015 by PB666

[YNM]

@ PB66: Look up the double-disk dark matter hypothesis paper. They used some limit (Oort limit or so ?) for ensuring that the dark matter disk won't interrupt what we see today. It's pretty detailed, including some proposed particle interaction at the end. And then I don't fully understand feynman diagram so I can't tell what they are !

@ K^2 : Hmm... scattering, now that makes some sense... Say, what if we look up the spectrum of faraway galaxies, preferably lensed by (supposedly) clumps of dark matter, would they have different spectra ? Maybe there's a limit on how low the photon energy have to be so it can interact ? The proposed dark-matter annihilation signal does have a quite narrow band (wavelength range)...

 

[PB666]

http://www.skyatnightmagazine.com/news/young-galaxies-found-dark-matter-structure?

This link is not strictly about dark matter. 

 

The idea is that the intersection of putative dark matter filaments seeded the gravity neede to nucleate massive galaxies.

[manaiaK]

On 1/12/2015, 5:44:49, K^2 said:

[mention of interferometers]

Telescope won't help you.

We are looking. We are finding zilch. We can't really be looking any harder with tech we have, and probably won't be able to even with tech we can invision.

My apologies, I was speaking too informally when I said "telescopes". I meant measuring instruments in general.

I am aware that reasoning by analogy can lead you astray, but...

When you're looking for a weak electrical signal, having a high background level of electrical noise is unhelpful. Likewise with weak sound signals: high levels of ambient noise get in the way.

So why would it be different for gravitational effects? There's a lot of "gravitational noise" in the inner solar system; getting away from that a light-year or so would help with detecting weak signals, I'd have thought. We need to do our searching from a quieter place.

[PB666]

2 hours ago, manaiaK said:

My apologies, I was speaking too informally when I said "telescopes". I meant measuring instruments in general.

I am aware that reasoning by analogy can lead you astray, but...

When you're looking for a weak electrical signal, having a high background level of electrical noise is unhelpful. Likewise with weak sound signals: high levels of ambient noise get in the way.

So why would it be different for gravitational effects? There's a lot of "gravitational noise" in the inner solar system; getting away from that a light-year or so would help with detecting weak signals, I'd have thought. We need to do our searching from a quieter place.

just a light year, piece of cake. we'll just send a wave detector and wait 9000 years and remotely flip the switch, what could go wrong?

[manaiaK]

16 hours ago, PB666 said:

just a light year, piece of cake. we'll just send a wave detector and wait 9000 years and remotely flip the switch, what could go wrong?

As I said at the start, we're not trying hard enough. Doing just the easy science is a good way to miss things. (Insert joke about a drunk looking for his lost keys under a street light rather than in the shadows where he lost them here.) We have the technology, we just need the commitment.

[PB666]

What technology, more vapor ware. At best, highly optimistic, we can get a post-jupiter radially velocity of 10^5/s, a lightvyear is 9.5x10^15m, year is 3.2x10^7. This means that optimistically you can travel radially at 3.2x10^12 per annum thats basically 1/3000 of a light year. No energy supply would last more 100 years, no means of creating a radially velocity of 10^6~7 m/s means the mission is not possible. 

 

Edited December 13, 2015 by PB666
glitchy

[RainDreamer]

We don't have the tech right now, and getting an organization to observe a singular mission like that for a few thousand years require a religious level of commitment. Maybe we need a few hundred years more of advancement. Maybe less. But a mission of this scale is out of our reach at the moment.

[manaiaK]

Ah, great! Some people who are realistic about the difficulty of extra-solar travel, unlike some of those on the "Interstellar/Martian" thread.

Yes, a light-year is currently beyond our reach both technically and politically. But how about 200 AU? That distance would attenuate the inner-system noise to some degree.

[PB666]

Here is the latest installment to the controversy

http://www.space.com/32295-super-heavy-dark-matter-particle-proposed.html

These are sub-blackhole size particles

According to the authors these things are spun out of inflation.

There are several problems I have with this.

1. The current model is that following inflation was followed by
-a. the pair production period (along with massive amounts of exotic matter), which terminated with an essentially expanding (now inertially) plasma universe - this is effectively the big bang. Namely because whatever happened before was big, but not associated with normal matter.
-b. because of the high initial density of energy and d(CMRF-U_cog)/dt for any given particle that the energy density per unit space dropped per unit time. This means that plasma densities fell, but also that the movement of particles away from each other as they moved into other CMRF (comoving reference frames - the average motion of protons), particularly electrons meant that at some point electrons had to slow down relative to protons and this meant that molecular hydrogen and deuterium-hydrogen could form.
-c. With this happening the density of the universe was increadibly high and as space cooled down, hydrogen coalesced into the first generation of stars, because these stars were only made of hydrogen they had to be massive to ignite, and because of the need to be massive they emmitted light at hydrogens unltraviolet, xray and blue wavelengths
-d. this causes space to reheat, but  unlike CMBR, it reheated space unevenly and the astronomical evidence currently suggests that there are starfields that deeply penetrate the reionization period that are also older than most visible first  generation galaxies. This then puts reheating out of the initial inflationary period.

The other problem I have, while it may be true that during inflation lots of exotic material/energy could have flowed into an emerging space-time, if alot of stable gravimetric material flowed into the universe, from all that I have read the universe was essentially awash with material instability, nothing could really survive, the ultimate fate of these high energy densities was ultra-high gamma radiation. With further expansion these shifted energies downward. The problem is that if a near black-hole particle formed, the absorption of hv would have easily converted them to bh. The density would have been so high in fact it would have been nearly impossible to prevent hv interactions (superposition) on top of particles that would have instantly created black holes all over the place. The plasma of the current universe would have simply been gobbled up. The caveot here is maybe GBH were created at then end of inflation, but we have to remember that setting inertia aside the universe is basketball size or smaller, you cant get the universe quantity of galaxies worth of black holes inside a basketball and expect things to go well. 

[PB666]

https://www.quantamagazine.org/20160412-debate-intensifies-over-dark-disk-theory

Dark gravity welcome to Dark Disks.

[PB666]

https://www.insidescience.org/content/astrophysicists-probe-expansion-universe/3901

Dark gravity mapping the visible universe

[PB666]

https://www.sciencedaily.com/releases/2016/05/160524212015.htm

There could be some truth to this, but if it was a complete explanation there would be far more distortions in our view of the deep cosmos.

Edit: Another link added.

https://iopscience.iop.org/article/10.3847/2041-8205/823/2/L25

Edited May 25, 2016 by PB666

[PB666]

http://www.scilogs.com/the-dark-matter-crisis/2016/07/09/dynamics-of-local-group-galaxies-evidence-for-a-past-milky-way-andromeda-flyby/

Basically this fellow argues that Dark Matter cannot be the only component of Dark gravity. 

As many of you know, i have argued that the universal gravitational constant may not be constant, in fact it has a variation about 100-1000 fold higher than that seen with the planck's constant. 

http://scitation.aip.org/content/aip/magazine/physicstoday/news/10.1063/PT.5.7282?utm_source=Physics Today&utm_medium=email&utm_campaign=7309141_The week in Physics 4–8 July&dm_i=1Y69,4CNRP,E1NXYI,FYL9V,1

Gravity is an observation of the warping of space-time due to matter and energy, but the warping of space time is mediated via the so-called quantum foam which technically appears only to exists in quantum time scales and resolves into something else relativistic space-time, (pulses of which we have measured using LIGO). We presume the interactions occur through the misnamed quantum gravity, how it creates the foam seems to be a puzzle, tobdescribe the foam as a collecion of shapes like cells in a body would be misleading, given quantum superposition, and the fact that energy in fields such as photons can contribute to the foam indicates very complex psuedo-structure. But the foam itself is critical to everything and at one time was the single most important determinant in the universe, now the interactions are weak and accumulative in nature (notable in things like black holes solely because we cannot see information on the other side of the event horizon). If we want to measure the gravitational attraction between an electron in the sun and a single electron on earth it would register as a microscopically miniscule value, so small, in fact, it could never be measured.  And yet the foam is composed of such tiny 'interactions'. How do these come to create gravity? 

[WinkAllKerb'']

yup yup the i live 0 years to 145 150 (insert exact accurate max number here) max ; i(we/whoever) study that stuff "since (? when ? mmmkay cool ...)" and i do believe photon don't die or fade away again serieZzzzzZzzzzZzzzzz take you time gonna bode well ... in the meanwhile everithing is normal as per gauss ... ralalalallalalalalala

 

(2034 soon how is lisa ?)

Edited July 11, 2016 by WinkAllKerb''

[Diche Bach]

I've missed threads like this in the years I've been away from this forum

[kerbiloid]

18 hours ago, PB666 said:

. If we want to measure the gravitational attraction between an electron in the sun and a single electron on earth

Better between two gravitons.

[PB666]

http://www.newswise.com/articles/view/657543/?sc=rssn

http://www.physicscentral.com/explore/plus/timeless.cfm

Bottom line . . . not detectable as a particle.

Edited July 21, 2016 by PB666

[KSK]

On 1 December 2015 at 7:33 PM, justidutch said:

Who is Eddie?

Please forgive me, I couldn't resist the Arthur Dent reference!

And more importantly - is this his sofa?

On 1 December 2015 at 6:09 AM, RainDreamer said:

Off topic: I find it hilarious how scientist came up with names like WIMP or MACHO and have them go against each others. I am not going to believe that someone DIDN'T spend an evening coming up with these names just for them to appearing in distinguished scientific journals as a joke.

Nor am I.  Molecular biologists are even worse when it comes to naming proteins. Take Ring ligases for example. Important proteins and I always figured the Ring part referred to their structure in some way. Nope - it's an acronym for Really Interesting New Gene. And then there's this famous paper.

Scientists enjoy a joke just like anybody else. Heck judges do as well - some judgements can be wonderfully snarky whilst also being exceedingly polite and formal.

[PB666]

1 hour ago, KSK said:

And more importantly - is this his sofa?

Nor am I.  Molecular biologists are even worse when it comes to naming proteins. Take Ring ligases for example. Important proteins and I always figured the Ring part referred to their structure in some way. Nope - it's an acronym for Really Interesting New Gene. And then there's this famous paper.

Scientists enjoy a joke just like anybody else. Heck judges do as well - some judgements can be wonderfully snarky whilst also being exceedingly polite and formal.

How about ZYXIN (name after the last 3 letters of the alphabet)   or    TNFRSF14 gene produce. Alias HVEM, HVEA, TM2.

[PB666]

Duck the popups!

https://www.newscientist.com/article/mg23130852-800-ghostly-particle-groups-could-explain-why-gravity-is-so-weak/

 

[PB666]

http://www.sussex.ac.uk/newsandevents/index?id=42599

The matter part of dark gravity may not exist, I think that dark gravity is probably defined by energetic fields and not particles that have a rest mast.

[Steel]

18 minutes ago, PB666 said:

http://www.sussex.ac.uk/newsandevents/index?id=42599

The matter part of dark gravity may not exist, I think that dark gravity is probably defined by energetic fields and not particles that have a rest mast.

There are still plenty of other dark matter candidates other than axions.

Also, if there is a field there are likely particles. After all, particles are just local excitations of a field (i.e. the Higgs boson is just a local excitation of the Higgs field)

[PB666]

I think something like 3 of the 4 major candidates have now been ruled out.

Higgs is massless, but it could be a type of Boson that increases gravity in empty space. IOW its rest energy is much greater than higgs.

Edited November 18, 2017 by PB666

[Steel]

53 minutes ago, PB666 said:

I think something like 3 of the 4 major candidates have now been ruled out.

Higgs is massless, but it could be a type of Boson that increases gravity in empty space. IOW its rest energy is much greater than higgs.

I believe there are still some WIMP candidates still in play, like the right-handed neutrino.

Also the above study has not actually ruled out axions totally, they could still exist with a mass outside the range that was excluded by the observations.