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Elusive Dark Matter May Be Detected With GPS Satellites
An anonymous reader writes: Two researchers say time disparities identified through the network of satellites that make up our modern GPS infrastructure can help detect dark matter. In a paper in the online version of the scientific journal Nature Physics, they write that dark matter may be organized as a large gas-like collection of topological defects, or energy cracks. "We propose to detect the defects, the dark matter, as they sweep through us with a network of sensitive atomic clocks. The idea is, where the clocks go out of synchronization, we would know that dark matter, the topological defect, has passed by."
Another reader adds this article about research into dark energy:
The particles of the standard model, some type of dark matter and dark energy, and the four fundamental forces. That's all there is, right? But that might not be the case at all. Dark energy may not simply be the energy inherent to space itself, but rather a dynamical property that emerges from the Universe: a sort of fifth force. This is speculation that's been around for over a decade, but there hasn't been a way to test it until now. If this is the case, it may be accessible and testable by simply using presently existing vacuum chamber technology
There is ample observational evidence of dark matter in the form of its gravitational effects. We just don't know what it is. It could be 'ordinary' baryonic matter or something entirely new. It isn't a matter of faith. Pun intended.
It can't be "ordinary baryonic matter": we know it doesn't interact with photons even at extreme energy densities, and we also know it doesn't move at or near the speed of light. Both are clear from the CMBR data.
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tt can be baryonic matter, if it is encapsulated in some fashion. I believe your two conditions refer to BBN (not a particularly extreme energy density, BTW) and the Lyman Alpha constraints on Warm Dark Matter (which means it had to drop out of the radiation fluid v ~ c / sqrt(3) pretty early).
Both of these are fulfilled by, e.g., quark nugget dark matter (these would form well before BBN and drop out of the radiation fluid well before needed to fulfill the WDM constraints), as maybe also the recently proposed "macros".
can be baryonic matter, if it is encapsulated in some fashion.
In which case it would hardly qualify as ordinary baryonic matter...
No, the reason the Higgs is called the god particle is because you can't have Mass without it.
The fundamental problem with the "standard model" is that it's based on gravity.
Actually the one thing that the Standard Model is absolutely NOT based on is gravity. Gravity being so weak and have an long range actually is responsible for the structures at the largest scales of the Universe which is precisely where we see Dark Matter. The reason for this is that EM is so much stronger that it will force charge cancellation to a large high degree on smaller distance scales: if there is a charge imbalance opposite charges will be rapidly dragged in to create a balance. This cancels EM out at larger distance scales since the charges balance leaving only gravity (the strong and weak nuclear forces being short range [~nucleus] due to their physics).
"Quark nuggets" are ordinary?
Well, I guess that would be technically correct (the best kind of correct!) if true, since 85% of matter is whatever dark matter is. Our matter is the weird stuff.
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Don't we have to have faith that the scientists aren't cherry-picking chunks of data that give them (almost) the significance they want?
Remember Feynman, in "Cargo Cult Science", describing how experimenters replicating Millikan's famous experiment found ways to fudge their data to match his flawed results? Didn't they have faith he was right?
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Faster! Faster! Faster would be better!
Satellites? Okay, here's one for you. The Voyager spacecraft. It traveled outside the solar system and the only minute unpredictable change in vector was due to heat radiating infrared photons from its metal. The measurements were THAT sensitive! And it interacted with exactly zero dark matter. You think some GPS satellite orbiting Earth is going to come up with different results?
CERN said the evidence is five sigma or so for a particle more or less where the Higgs was expected (or perhaps about halfway between where two competing theories expected it), but some now doubt whether the particle CERN found is actually the Higgs. See this recent reassessment: http://sdu.dk/en/Om_SDU/Fakult...
Sure, I'll give it a try. If you put two bar magnets next to each other, they tend to flip each other around so that they point in the same direction. Now try to picture an infinitely large universe, which is filled with an infinite number of tiny bar magnets. If all of these magnets pointed in the same direction, there wouldn't be much interesting going on; since all the tiny magnets are already aligned, they won't try to flip each other over, and the universe would be a stable place. (You could still have some fun by flipping a few magnets, and watching the ripples spread as a wave throughout the universe; but that's not what I'm gonna talk about now.)
But let us now consider a different scenario: in one end of the universe, all the magnets are pointing "up", while in the other end of the universe, all the magnets are pointing "down". By themselves, both these regions are stable, since there is nothing inherently "better" about pointing up than pointing down. However, somewhere in between these two far ends of the universe, there has to be a region where the magnets change from pointing up to pointing down; and this is a region of higher energy, since you have all these tiny magnets which are constantly fighting among themselves about which way to point, and constantly trying to flip each other over. This is called a "domain wall" in the case of magnetism, which is an example of a "topological defect". This domain wall can be moved and twisted by flipping a finite number of magnets in the vicinty of the domain wall; but you can't truly get rid of it without flipping an infinite number of magnets throughout the universe, which would end up requiring an infinite amount of energy.
In some quantum field theories, you get analogous situations where a theory has multiple stable "vacuum solutions". If the universe contains fields like that, we would then have two possible scenarios: (i) the entire universe has the same vacuum state (corresponding to all the magnets pointing in the same direction); or (ii) the universe could in principle consist of different stable regions with different vacuum states, with an unstable region called a "topological defect" inbetween, where the different vacua fight for dominance.