Gamma rays from the Milky Way's core look ever more like signs of dark matter | Hacker News Reader

Gamma rays from the Milky Way's core look ever more like signs of dark matter

economist.com

51 pointsuniverse52022 comments

Treat this article with skepticism. I think the journalist has badly misjudged the current consensus in the field when they say:

"There are still a few die-hards who do not believe in hooperons. They suggest that if an ensemble of millisecond pulsars (dead stars that rotate hundreds of times a second) were buried in the Milky Way’s middle, that might do the trick."

The way I hear it, a population of new point sources is a better match for the Fermi data than dark matter --- the excess is "clumpy", indicating point sources, when you would expect a dark matter signal to be diffuse.

My high school physics professor had a motto: "Good enough is not good enough." This was generally in response to the imprecision of lazy students who would say to themselves or their lab partners, "Good enough." It's something I've carried with me in life in a lot of contexts.

So it was fun seeing Dr. Goodenough's name in the article.

Alas, her name is pronounced ~Good-en-know, not Good-en-nuff.

Funny, I didn't see that in her name.

I know this betrays my ignorance but it just seems that dark matter is a rather implausible explanation for the apparent evidence of additional gravitational force being exerted.

"must outweigh familiar, atomic, matter by about six to one" but despite our best efforts it cannot be detected but there's vast amounts of it.

It seems to me there must be a better explanation because so far this one (i.e. it's there but we just can't detect it at all) just doesn't make sense.

Ah yes, the classic response to dark matter.

But you should know that this is precisely the same response that scientists took to dark matter. They have spent decades doing numerous studies and experiments trying to nail down the source of these unusual observations that might be "dark matter". And in every single case, again and again they've eliminated everything else it could be and focused in on a very tightly constrained explanation: weakly interacting massive particles traveling at very sub-relativistic speeds (aka "cold dark matter"). The dark matter/WIMP theory has now been verified to an enormous degree across a variety of different observational fronts. Nothing else fits the bill no matter how hard we try, only a very specific dark matter theory fits the evidence.

And it's not unprecedented, we know of other types of dark matter (such as neutrinos) though we know such things don't make up the bulk of the mass that appears to be out there. We have detected it, time and again, we just haven't observed it directly. Nor do we know exactly what it is, though we have some strong suspicions based on likely extensions to the standard model.

There really is no better explanation.

We have good reason to believe that when we talk about dark matter, we really are referring to some kind of "stuff" that has mass and momentum, but doesn't interact electromagnetically with normal matter.

The most visually striking evidence comes from the Bullet Cluster. We can see two galaxy clusters that have recently collided at ~1% of the speed of light, causing the gas to be slowed and heated. And we can map the mass distribution via gravitational lensing, and see that a large amount of the clusters' mass has passed right through each other without being slowed. This is more or less what you would predict if "dark matter" is made of weakly-interacting massive particles (WIMPs), and is pretty hard to explain by appealing to a modified law of gravity.

http://chandra.harvard.edu/photo/2006/1e0657/index.html

https://en.wikipedia.org/wiki/Bullet_Cluster

Could it be that dark matter is stretched out along an axis that's invisible to us and gravity? Maybe the particles don't interact with each other or anything else because they're not actually that close to each other except when projected onto the dimensions familiar to us, and on which gravity acts.

> despite our best efforts it cannot be detected but there's vast amounts of it.

But we have detected it, to the best of our present capabilities. We've measured how much baryonic matter are in formations, calculated how much mass is needed to keep the structure together and spinning, and come up short. That shortness is dark matter. It's sort of evidence by absence. There is something there that has mass but doesn't experience EM forces.

Either that, our our theory of gravity is wrong on a very fundamental level. On proposed alternative, that describes the motion of some stars without missing any mass is MOND: https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics

We have in fact detected one type of dark matter - neutrinos. They aren't sufficient to account for the mass needed to explain observations, but they are definitely dark matter in that they do not interact electromagnetically with regular matter.

The problem with modified gravity, is that it requires a lot more theoretical complexity to explain observations like the Bullet cluster and galaxy rotation, and the large-scale distribution of matter in the observable universe. Ie. a modified gravity theory that works for one of those observations, fails for others. Slow, massive dark matter clouds explain all of them quite nicely.

Neutrinos are made out of 6 prisms and they normally decay into 4 prisms. Those build up the grid structure of our vacuum.

another problem with MOND is, that it is in my opinion and a friend of mine that is more deeply into logic, not a classical logical explanation. We have no prove in a logical sense yet, but we both had the feeling that you need some more complex logic to get satisfy the max function in MOND. I asked my old logic professors, but did not get an answer...

It's not theoretically undetectable, just very hard to detect, to the point that we haven't yet been able to do it. This article suggests that finally, we may be able to see it other than via gravitational effects.

For a long time I also subscribed to the idea that the missing matter was better explained by faulty math, somewhere, but as our observations get better it's looking more and more like there's really something there, that behaves independently and differently than the matter we know.

I don't question that the effect is there.

I just wonder if it isn't a side effect of some other (not understood) aspect of the universe rather than the result of the behaviour of some particle.

To illustrate, gravity per se doesn't exist, it's the outcome of the bending of space towards mass. So it's effect is real but it's not because some sort of gravitional particle is acting.

> ...but despite our best efforts it cannot be detected...

Keep in mind that virtually every way we have of detecting things involves electromagnetism. If there were to be some form of matter that does not interact with the electromagnetic force, then there would be very few ways we could actually detect it, gravity being one of them.

I understand there are alternate theories based on gravity changing over time. That seems conceptually more satisfying to me, but then I'm not a physicist, so perhaps they're out to lunch.

Also see http://www.scientificamerican.com/article/dark-matter-explos...

Edit: I find this 2011 paper, but nothing newer: http://arxiv.org/pdf/1010.2752v3.pdf

Maybe someone can point to their latest stuff.

"and particle physicists will have six times more stuff to study than they had before."

Can anyone out there explain this statement for us non-physicists?

They're echoing a statement made in the third paragraph: "Everything from the motions of galaxies to calculations about what sort of universe came out of the Big Bang says it [dark matter] must exist—and must outweigh familiar, atomic, matter by about six to one."

There's roughly five or six times as much dark matter in the universe as there is conventional matter.

Dark Matter is apparently 84.54% of our Universe. If this is so abandoned, why did the millions we spend looking for it did not yield anything ?

Lets see:

http://arxiv.org/pdf/physics/0612201.pdf http://arxiv.org/pdf/1004.0716v3.pdf

If you go through the list of papers on the Michelson-Morley experiment, you will see that it is not that clear. In fact, they did a lot of things wrong then. Averaged values that should have not been, missing information about the movement of the solar system around the galaxy core (~360 km/s), gas mode instead of vacuum,...

There are many critical papers published over the years:

http://arxiv.org/find/all/1/all:+AND+michelson+morley/0/1/0/...

This is a very nice list of better experiments, looking into those is very interesting:

http://www.helical-structures.org/new_evidences/modern-ether...

Einstein only later understood, that general Relativity without aether is unthinkable (Sidelights on Relativity): """ Recapitulating, we may say that according to the general theory of relativity space is endowed with physical qualities; in this sense, therefore, there exists an ether. According to the general theory of relativity space without ether is unthinkable; for in such space there not only would be no propagation of light, but also no possibility of existence for standards of space and time (measuring-rods and clocks), nor therefore any space-time intervals in the physical sense. But this ether may not be thought of as endowed with the quality characteristic of ponderable media, as consisting of parts which may be tracked through time. The idea of motion may not be applied to it. """

He did not need aether for SR, but GR without aether, simply does not make sense. Also radial waves as predicted by Lord Kelvin and discovered by Tesla are not really understandable without. You can explain many virtual particles by creating a zoo like the standard model did, but radial waves you can't.

Dark Matter is the aether, without it's mass, spiral galaxies and many other cosmological phenomena are not explainable - or at least not classical.

The problem with most aether theories is, that they assume it as some sort of superfluid, or some special substance, which both do not make so much sense, as the complexity of the vacuum is simply to great. It must at least implement all virtual particles (β+/β-/photons/...), electric and magnet fields (Hertz & Tesla waves, as both exist),...

The BSM-SG model has a completely different aether model, instead of some special substance, it is made of the same building materials as protons/electrons, just in a much smaller and different geometric structure.

It has only one fundamental force and 2 very simple fundamental particles (balls). It becomes clear, that already quite large crystals, that look like prisms, under this one law of attraction, build a grid that looks like a 3d honey web.

In this grid, you can find all the physical properties we can measure. Electric and Magnet Fields, Speed of Light, Photons, Vacuum Fluctuations, Gravity, Coulomb Barrier, Quantum Entanglement, Virtual Particles (without rest-mass)....

Of course, many of those are iterations between the extremely complex geometrical structure of electrons/protons/neutrons and the Cosmic Lattice as its called in BSM-SG.

Best physics book I read and most sensible unified theory I have encountered so far:

http://www.amazon.com/Basic-Structures-Matter-Supergravitati...

Needs an open mind tho and some months of heavy thinking for really getting into this theory, but once you grasp the basic interactions, geometric structures etc the universe starts to make so much sense. So far, every phenomena I encountered was explainable after some minutes-days of thinking and I always came to the same conclusion as Stoyan Sarg.

The universe is classic logical :)

To put it in perspective for those who actually read through it: the aether that Einstein was talking about has nothing to do with a classical definition of aether from Michelson-Morley times and, of course, connection to dark matter is solely grammatical.

Since when did HN become an "alternative science" magnet?

I'm absolutely sure, that Einstein would have gone with the BSM-SG model. Unfortunately traveling back in time is impossible (from the BSM perspective).

Because the BSM model is the hacker approach to physics. If you can't unify a theory in 100 years, you most likely made some mistakes and a rewrite makes much more sense. Start from scratch with newest measurements and the simplest assumptions build it from ground up. Of course you must describe the different constants/forces of the standard model, but as long as you derive them logically, its absolutely valid.

Sorry, but we run out of time to wait 100 years for general physics to catch up. Paradima changes are slow, and we run out of time. Most people do not understand the great danger we are in:

arctic methane is just one of it: https://www.youtube.com/watch?v=m6pFDu7lLV4

If somebody gives me a classical theory of physics with the absolute minimal set of basic assumptions possible; that fits measurements very well, uses a more strict form of logic and provides one with a physical understanding of something that could save humanity:

I fucking taking it. I learn the crap out of it and I give my best to save this wonderful planet that we trashed. I studied physics long enough that I know how most, not all of course, tick. I understand the close mindedness of many scientists.

That's why I'm promoting it, that's why I think it deserves a chance to be investigated. Quite often, when I talk with people about this model, hackers have a much more open attitude to new ideas and very often, after answering many of their questions, I often here: ohh, this actually makes sense. Especially chemists are very fast interested, because it explains, of course, chemical bindings and the interaction between particles very well and understandable.

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