back to article Boffins say dark matter found with X-ray

Two teams working on the search for dark matter have independently suggested the search could concentrate at a specific X-ray wavelength, following study of data collected by the XMM-Newton space observatory. While it's not a proof of anything just yet, the two groups – one from the Harvard-Smithsonian Centre for Astrophysics, …

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Paranoia

Some days I wonder if we're sandboxed and just trying to hack our way out of the most sophisticated hypervisor ever created.

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Re: Paranoia

That's a semi-rational position; cf the Singularity or Tipler's take on the Omega point. And if we're running inside a simulation, then the system might have "bugs" At which point you become a crackpot looking for miracles and the supernatural.

But how you get to all that from these papers, I'm not sure. I read the first one a while back, and it's coquettish but will probably turn out to be misunderstood astrophysical process. :(

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Re: Paranoia

This is fundamentally a religious position, which is why I don't believe it.

Physicists joke that all other sciences are stamp collecting, but the insight of evolutionary biology - that there is no intelligent design and no plan - still seems to pass some of them by. That, or they are just careless in use of language. Even Hawking has been caught in speculative metaphysics.

The idea that we occupy a spacetime which is a subset of an overall spacetime with more dimensions may or may not be correct, but it has its origins in Eastern religions - Hinduism, for one. For that reason it has to be a bit suspect, as it postulates things that are unobservable. The idea that we inhabit a "brane" in spacetime which might be influenced by scalar fields from other branes is so close to some of the weirder mystical ideas that it should be subjected to a great deal of scepticism.

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Re: Paranoia

"This is fundamentally a religious position, which is why I don't believe it."

Agree. The same skepticism applies to attempts to find "meaning" in CP violation, or cosmological findings.

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Anonymous Coward

Re: Paranoia

Let's hope we don't get reverted to snapshot any time soon.

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Re: Paranoia

"I read the first one a while back, and it's coquettish but will probably turn out to be misunderstood astrophysical process. :("

Maybe, maybe not. Solar neutrinos change flavor seven ways till Sunday. It is possible that another state exists that is at a longer time factor till change.

They're not *that* well understood yet. Only reasonably understood.

But, it's equally possible that you're correct.

Only time and tons of effort in research will tell.

But, I find that cool. After all, if we understood *everything*, life would be infinitely boring! :)

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Re: Paranoia

"Even Hawking has been caught in speculative metaphysics."

Hawking pulled black hole theories out of his buttocks, but made them work and observation has proved quite a bit of his theories. So, speculative "metaphysics" is just speculative *physics*.

"For that reason it has to be a bit suspect, as it postulates things that are unobservable."

Nuclear physics started out postulating things that were unobservable, then clever men and women invented ways to observe the nuclear, then sub-nuclear.

If we had adopted your view, even germ theory would've been ignored!

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Re: Paranoia

"Agree. The same skepticism applies to attempts to find "meaning" in CP violation, or cosmological findings."

CP violation exists. Finding a reason for it helps explain the most fundamental factors of our universe. If CP parity existed, why isn't Venus made of antimatter?

Or Jupiter.

Obviously not even Mars.

Still, great claims require great proofs. One can only prove or disprove something by examination and experimentation. One does *not* prove or disprove by dismissal.

We'd still be in the dark ages were that true!

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Joke

Re: Paranoia @Wyzrd1

"Obviously not even Mars." I don't know....when you get that awful goo under your denture, you begin to wonder!

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Re: Paranoia

BAG: That's a semi-rational position

Well, of course it is; any solipsism can be articulated as a series of logical extensions from a premise that can't be confirmed or refuted. The "computer simulation" parlor game (under "Singularity" or "Omega point" or whatever description) is just an ancient sophomorism in science-fictional dress.

If you take Danto's scheme, for example, in which all philosophies consist of some attempt to explain the relations among members of the tuple {subject, world, representation}, then solipsisms are just those attempts that deny any informative connection between representation and world.1

ATL: This is fundamentally a religious position

Well, no, it is not, in any useful sense. While any endorsement or rejection of the initial solipsistic thesis must be a matter of faith (because it's untestable), "religious", to be a useful term, needs to signify a particular class of matters of faith (those attributed to an intentional supernatural agency) - otherwise the term is redundant and divorced from its etymological and common meanings.

The idea that we occupy a spacetime which is a subset of an overall spacetime with more dimensions may or may not be correct, but it has its origins in Eastern religions - Hinduism, for one.

It has cognates in Indian philosophies, but it also has them in European ones. The resemblance is not sufficient to demonstrate influence.

1For Danto, see Connections to the World. The introduction of information as the defining attribute is my own but, I claim, in keeping with Danto's model. It does permit some faux-insightful cocktail-party ruminations on the relationship between solipsism and information theory, encryption, and the like, which I offer under liberal licensing terms to unscrupulous intellectuals looking to bamboozle inappropriate potential targets of their mildly-horrifying affections.

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So this is the first part of "Now that looks a bit funny" and is now at the point where bigger toys and brains get focused on it.

Let's all strap in and enjoy the ride :)

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Anonymous Coward

The problem with all of these looking for dark matter thingies, is they're all premised on dark matter having some detectable presence in the EM field. Yet all of the claims about what dark matter does/constitutes suggest that it doesn't have any EM properties.

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Headmaster

That's not how it works.

Here we have a sterile neutrino population (definitely not interacting via electromagnetism and apparently not via weak force either) generally just sitting there like a heavy gas around galaxy cluster, but now slowly (i.e. with half-life times >> current age of the universe) decaying into a photon (the detected signal) and a standard neutrino (undetectable again).

It's only the decay signal you can observe. More clearly:

How can we see if this is the right model? Dark matter that has no interactions with the visible matter seems hopeless. Fortunately, sterile neutrino dark matter is expected to decay and produce a smoking-gun signal in the form of a monochromatic photon line. This is because, in order to be produced in the early universe, the sterile neutrino should mix slightly with the active ones. In that case, oscillations of the active neutrinos into sterile ones in the primordial plasma can populate the number density of sterile neutrinos, and by this mechanism it is possible to explain the observed relic density of dark matter. But the same mixing will make the sterile neutrino decay, as shown in the diagrams here. If the sterile neutrino is light enough and/or the mixing is small enough then its lifetime can be much longer than the age of the universe, and then it remains a viable dark matter candidate. The tree-level decay into 3 ordinary neutrinos is undetectable, but the 2-body loop decay into a photon and and a neutrino results in production of photons with the energy E=mDM/2. Such a monochromatic photon line can potentially be observed. In fact, in the simplest models sterile neutrino dark matter heavier than ~50 keV would produce a too large photon flux and is excluded. Thus the favored mass range for dark matter is between 1 and 50 keV. Then the photon line is predicted to fall into the X-ray domain that can be studied using X-ray satellites like XMM-Newton, Chandra, or Suzaku.

Also note that dark matter detectors assume that dark matter should interact at least via the weak force (they are "Weakly Interacting Massive Particles"). Same with the neutrino detectors. The electromagnetic force does not enter here.

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"Yet all of the claims about what dark matter does/constitutes suggest that it doesn't have any EM properties."

Not quite. Indeed, the Oort cloud is dark matter. It isn't glowing, it isn't shiny, we find what is found by looking for faint traces. The same is true for all distant, dull objects of debris.

It's rather likely that dark matter is just dust that was blasted away from stars entering main sequence and is quite diffuse, but it'd not *quite* explain the *quantity* required by gravitation laws as we know them.

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Maybe, maybe not. It could and quite likely is a red herring. But, one learns by observation, experimentation and theorizing.

One learns nothing by ignoring things.

Meanwhile, I recall some Solar neutrinos doing weird things that was unexpected at the time...

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Did they overlook the obvious here?

When I went to infant school, erroneously called elementary school across the pond, we were taught a thing in physics about opposites attracting. Magnets and all that right?

So sure the answer to finding dark matter is to put a bit of shiny matter in a room by itself and wait for some dark matter to appear..

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Re: Did they overlook the obvious here?

"When I went to infant school, erroneously called elementary school across the pond..."

We call infants creatures that are in diapers and incapable of walking yet.

So, either we have a terminology problem or your pre-toddlers are in school.

As I know far better from experience with British people and their education, it's obvious that infancy isn't when one is educated in a school.

I'll refrain from insulting the insult that is my home in the US poor excuse for an educational system.

My vast vocabulary fails to grant me the proper ability to do so.

In simpler terms, in the US, an infant is essentially capable of only suckling. Hence, an infant school is rather laughable.

Though, our schools qualities of late are also quite laughable.

In a sad laughter way.

Though, I did toy with the notion of teaching UK students about US federal, state and community law, upon proper consideration, I decided it wasn't worthy of doing so, lest the students become insane. ;)

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Re: Did they overlook the obvious here?

So, either we have a terminology problem or your pre-toddlers are in school.

Here in the US, my granddaughter started school at six weeks of age. She was definitely still an infant.

The school in question refers to its mission as "child care", but daily activities, even for infants, include both undirected and directed exploration, both of which have demonstrated pedagogical effects. If people working with children, in an organized and consistent fashion, outside the home, on a regular schedule, to help them learn, isn't "school", then I'm not sure what is.

That said, even at the now-advanced age of 13 months we have made very little attempt to teach her much in the ways of physics, beyond practical demonstrations of simple mechanics. So in the particular case posed by Dropper, I'd say "infant school" is no better a term than "elementary school".

Indeed, since etymologically infant means "incapable of speech", his use of "infant school" is harder to justify than the rather more vague "elementary". Etymology is not destiny, of course, but if we are playing warring terminology it's as valid an argument as any.

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Pint

Interesting observation

And as so often, it leads to a cry of "bring on better instruments" (and rightly so). This might be something radically new, this might be a different version of something old, it might be a glitch in the instrument (after all, both reports rely on the same instrument). That's science in progress for you.

Fortunately, the Japanese mission is not too far away in the future (certainly no astronomically speaking). I'll raise a glass to the progress made

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