Florida Physicist Says Dark Matter, Extra Dimensions Related And Possibly Detectable

spacedaily.com ^ | 19 May 03 | staff

[AndrewC]

The South Pole device, known as the Antarctic Muon Neutrino Detector Array, or AMANDA, is designed to detect particles with no electrical charge and no mass created in massive cosmic events such as supernovas.

Okay now, are they changing their minds again, or are they just out of the loop?

[Gary Boldwater]

Thanks for the alert! As always the key line:

"Dark matter has never yet been directly or indirectly observed. "

And now there's "dark matter particles". Next will be "dark matter virtual photons".

It's all Pagan Science. One virtual particle to explain this, hidden undetectable matter that does that.

There's better evidence that UFOs exist. There are photos, radar tracks and reliable witnesses.

I say change their funding to either the virtual type of the dark hidden type.

[Paco]

What about white matter and clear matter??? Don't any of these scientists have any gray matter?!?!? Do I have to figure this all out by myself again???

[RightWhale]

All this is to hype the physics program at the Univ of Flo. I didn't see the paper and there wasn't a link to a PDF version, so I assume this is all what-ifs, conversation between grad students waiting for the next class.

[Bloody Sam Roberts]

Pink Matter Alert!

Keep it clean!

[Bloody Sam Roberts]

I think it's more appropriately called "Howzit Matter".

Or rather, "Whatza Matter".

[farmguy]

According to one alternative theory, these additional dimensions might be curled up into a ball so small -- significantly smaller than atoms -- that they are difficult or impossible to observe.

Be careful with that. If you drop it, we'll never find it again...

[RightWhale]

If you drop it, we'll never find it again

That's the truth. It's so small we might not even find it in the first place.

[gcruse]

I say change their funding to either the
 virtual type of the dark hidden type.

Alright.  I shall put your request on my
list of things from which I nightly beseech
the invisible man in the sky who has never
been directly or indirectly detected.

[lonestar]

I have trouble understanding a lot of things I can see. I'm supposed to understand things I can't see?

I'll think about that tomorrow.

[RightWhale]

Manyana is the busiest day of the week.

[MHGinTN]

"... no one has ever found more than one dimension in time and three in space." Now, if they would change the wording to read '... no one has ever found more than one variable of dimension time and three variables of dimension space.' This might make more sense. After all, there existed a present that we passed through to reach the present we inhabit and we are moving through time toward the future we have yet to reach. [Actually, we do not sense the present directly, we only infer it from the collected data of past events that impact our senses on a delay ranging from millions of light years to moments.]

[MalcolmS]

It's interesting they are using nuclear particle algebraic multiplication table entires to deduce behavior of intergalactic systems.

Given the computation power required to do this given lightspeed delay of gravitional effects simulating the motion of galactic bodies, I believe that this calculation is done assuming instantaneous gravitational effects!! Someone correct me if I am wrong.

[RightWhale]

If the dimensions are generalized there may prove to be fewer than these. Then we are dealing with Hamiltonian mechanics rather than Newtonian mechanics, a better situation altogether.

[RightWhale]

Algebraic multiplication turns out to be nothing more than symmetry operations, all of them rotation pairs, or you could say reflections. Translation can be taken as rotation about an infinitely distant axis as Rodriguez pointed out. This implies that there is only one particle and the variety we measure is only properties of the one particle. Therefore, calculations take no time at all, although in the model some CPU time is burned every time you do anything or even run a timing no-op.

[Tolerance Sucks Rocks]

We know this, anyway: there are things we don't know, things we know we don't know, and things we don't know we don't know.

Well, whaddya know!

[RightWhale]

And by (5) above, things we don't know we know, which completes the Rumsfeld set.

[concentric circles]

Physical Review Focus
Detecting Dark Dimensions

Dark matter arising from extra spatial dimensions could be detected with existing or future experiments, according to the 18 November print issue of PRL. If an additional dimension were hidden in the right way, heavier replicas of the known particles might traverse space and account for the mysterious "dark" component of the Universe's mass. Detecting the unique particles would potentially confirm the existence of extra dimensions and solve at least part of the dark matter riddle.

Researchers think that 30% of the Universe's mass is made up of unknown particles that are invisible to telescopes but have gravitational effects on galaxies. Potential culprits called weakly-interacting massive particles (WIMPs) come from proposed extensions to the standard model of particle physics, such as supersymmetry and extra-dimensional theories. To verify the theories, searches for some of these particles look to space, because particle accelerators are too weak to produce them. But the big bang should have produced every particle. "Maybe the Universe made them for us and they're floating around out there and are dark matter," says Jonathan Feng of the University of California at Irvine. "Now the [difficulty] is you have to find them."

Kaluza-Klein particles are named for the two theorists who first proposed that extra dimensions could be "curled up" to a size too small for us to notice them. In the simplest case, these particles would be much like those of the standard model, but would move through four spatial dimensions instead of three. Their momentum along the fourth dimension would appear as additional mass in three dimensions, so we would observe heavy photons or heavy electrons, for example. The smaller the extra dimension, the greater the mass.

Now Feng and his colleagues have found that Kaluza-Klein particles would heat up or ionize a block of material such as germanium at rates comparable to other dark matter candidate particles. They could also annihilate each other in space, creating showers of ordinary particles. The researchers calculated that Kaluza-Klein dark matter would generate a unique, sharp positron signal, distinguishing it from the neutralinos of supersymmetry. Because dark matter feels the gravitational force, it would be drawn toward the sun's large mass and lead to an excess of neutrino and muon showers from the sun's direction. The AMANDA neutrino detector, buried within the Antarctic ice, or the Alpha-Magnetic Spectrometer (AMS), an antimatter detector scheduled to fly on the International Space Station in late 2005, could hunt out these signals.

"Kaluza-Klein dark matter is definitely worth looking for with AMS," says Kate Scholberg of the Massachusetts Institute of Technology in Cambridge, who works on the detector project. "The indirect signature would be quite dramatic for some of the possible parameters they discuss." She adds that detecting and distinguishing Kaluza-Klein and supersymmetric dark matter would depend strongly on how nature actually behaves, but coming up empty wouldn't rule them out, just constrain their possible characteristics.

--JR Minkel

Kaluza-Klein Dark Matter
Hsin-Chia Cheng, Jonathan L. Feng, and Konstantin T. Matchev
Phys. Rev. Lett. 89, 211301
(issue of 18 November 2002)

PDF file of the original letter is linked at the above page but is available only to subscribers or for a fee.

[RightWhale]

One thing about relativity might apply to an extra dimension. When a particle is moving near the speed of light it appears to rotate at an angle depending how fast it is going. When the particle is moving at the speed of light it finally becomes 4-dimensional.

[Cogadh na Sith]

We know this, anyway: there are things we don't know, things we know we don't know, and things we don't know we don't know.

And, of course, as Heisenberg showed: There are things that are unknowable.

I've given this dark matter/extra dimensions/time conundrum quite a bit of thought, research and pondering.

It seems to me that 'time' (as in the cause/effect, before/after human construct) only exists inside the head of the observer. We manufacture time and causality as a survival instinct synonymous with 'self-awareness'.

The greater universe certainly doesn't follow our construct, thus the 'dark matter' is everything that is not the 'present'. It has both mass and quantum energy, but is impenetrable to us in our relative 'time-space'.

In 'non-time' space, imagine a small 'cube' of space. 'Now' there is nothing in it, it is space. Before, maybe there was stuff in it. Maybe there will be stuff in it later. All those 'potentialities' of no stuff/stuff in it carry weight and energy because they all exist at once. Our tiny 'conscious 'now-filter'' only shows us a time-slice of those potentialities (the energy of probability) and then fills in the rest of the story like our minds fill in the rest of a sliver moon.