Deflating Claims That ESA Craft Has Spotted Dark Matter

Yesterday, we posted news that data from the European Space Agency's XMM-Newton spacecraft had been interpreted as a possible sign of dark matter; researchers noted that a spike in X-ray emissions from two different celestial objects, the Andromeda galaxy and the Perseus galaxy cluster, matched just what they "were expecting with dark matter — that is, concentrated and intense in the center of objects and weaker and diffuse on the edges." StartsWithABang writes with a skeptical rejoinder: There seems to be a formula for this very specific extraordinary claim: point your high-energy telescope at the center of a galaxy or cluster of galaxies, discover an X-ray or gamma ray signal that you can't account for through conventional, known astrophysics, and claim you've detected dark matter! Only, these results never pan out; they've turned out either to be due to conventional sources or simply non-detections every time. There's a claim going around the news based on this paper recently that we've really done it this time, and yet that's not even physically possible, as our astrophysical constraints already rule out a particle with this property as being the dark matter!

Comments

Dark matter and the sniff test

[bradley13]

I'm just a lowly engineer, but for me "dark matter" has never passed the sniff test. It's a kludge factor thrown in to make equations balance. And a kludge factor so huge that "dark matter" is supposed to outweigh all of the observable matter in the entire universe. The only reason this doesn't sound ridiculous is because we've been hearing it for so long.

If you need a kludge factor that big, it is far more likely that the equations are wrong.

There are other possible explanations. For example, if the speed of light were a function of space and time, then the situation changes completely. All observations of the distant/ancient universe are suddenly thrown into question; the interactions within that distant/ancient universe were also different from what we see locally, today. This particular theory (variability of C) is one that crops up periodically, most recently in 2013. It is difficult to prove, but really, it's no more unlikely than the existence of huge amounts of dark matter that stubbornly refuse to interact with the known universe.

Re: Dark matter and the sniff test

[Anonymous Coward]

You're already been given one clear proven kind of "dark matter"; the neutrino. This is incredibly difficult to spot; interacts very little; is almost absent from normal ("small scale") physics and yet it's existence is clear and well evidenced. It's really not that big a stretch that there is something else.

The thing is that if there isn't someone has to come up with really clever expansions for a whole load of other stuff. This would not be nearly the first time a physicist was wrong. In fact a truly dedicated physicist should try took be wrong several times a day. However strange and contrary to instinct would rule out relativity and quantum physics; in fact most of what we know to be true about the world. You have to find something more than gut instinct to oppose this with.

Re:Dark matter and the sniff test

[wonkey_monkey]

I'm just a lowly engineer, but for me "dark matter" has never passed the sniff test.

And yet it seems like most physicists - of whom I am not one - seem to think it is the simplest explanation for what we see.

The quote in the summary sums up, for me, the somewhat churlish attitude some people adopt when faced with dark matter:

There seems to be a formula for this very specific extraordinary claim: point your high-energy telescope at the center of a galaxy or cluster of galaxies, discover an X-ray or gamma ray signal that you can't account for through conventional, known astrophysics, and claim you've detected dark matter! Only, these results never pan out;

Of course they have never panned out - so far. If one of them had panned out, we would have stopped looking. Your keys are always in the last place you look.

Photons started out their theoretical life as a kludge factor to solve the ultraviolet catastrophe (great band), and people were appalled by the idea.

Wait Just a Second

[Anonymous Coward]

Time and time again when the subject GLobal (not) Warming comes up all we hear from the would be Slashdot PhDs is "Peer Review! Peer Review!"

But somehow now it's just fine to dump all over the findings of a group of scientists...real scientists, with degrees and shit, not just a Slashdot handle and low UID) and not a mention of peer review in sight.

Fucking hypocrites, the lot of you.

Re:I'm also an engineer

[EdgePenguin]

You do not have a better theory. You have a hypothesis, posted on a webpage. This is timecube territory, sorry. Why is it that engineers make such laughably bad attempts to second guess scientists? And why do they insist on bothering actual scientists with mass emails about their crazy ideas?