Possible Dark Matter Signs At the Core 234
Scientific American has a piece on speculation that dark matter may be behind diffuse radiation in the galactic center. Beginning in 2003, researchers led by Douglas Finkbeiner noticed a curious excess of microwave radiation in the WMAP data, after all known sources of such radiation were accounted for. Data from NASA's Fermi Gamma-Ray Space Telescope resulted in a similar anomaly in gamma rays. "A paper posted to the physics preprint Web site arXiv.org on October 26 and submitted to the Astrophysical Journal points to a possible signature of dark matter in the Milky Way, although the study's authors are careful to keep their observations empirical and table such speculation... In the new paper [the researchers] describe the Fermi gamma-ray haze and make the claim that it confirms the synchrotron origin of the WMAP microwave haze. And as with the microwave haze, the authors argue that the electrons responsible for the gamma-ray haze appear to originate from an unknown astrophysical process. ... 'We are absolutely in the process of exploring the Fermi haze in the context of dark matter physics,' [one of them] says."
Re:Explanation Impossible (Score:5, Insightful)
The difference is that dark matter and dark energy can be tested for in various ways; a deity can't be.
When physicists can't explain something they may use a place holder at times but there's no chance of just giving up like the "god did it" explanation does.
Re:Explanation Impossible (Score:0, Insightful)
Dark Matter and Dark Energy are like the modern equivalent to Phlogiston. Either something is wrong with our model or missing from our equations so in order to make the math work we insert a known unknown. It makes the equations match up with the observations cleanly, but requires us to assume something about the nature of the Universe that just doesn't make sense. Phlogiston was exactly the same. We could not explain the bizarre eddies of the outer planets from the perspective of a geocentric system so we introduced unobservable eddies which made the math work because our model was wrong. Something tells me that we'll eventually work out a more accurate and more elegant model that doesn't include Dark Matter or Dark Energy in the future.
Re:One word: (Score:3, Insightful)
Re:Explanation Impossible (Score:3, Insightful)
There appears to be something out there that interacts gravitationally with normal matter but does not glow or reflect light. Doesn't glow:-> dark. Has gravity: -> matter. Therefor we call it "dark matter", for now.
Re:It's a black hole! (Score:3, Insightful)
Re:It's a black hole! (Score:3, Insightful)
It looks like they're claiming that the radiation from these electrons indicates that a process of higher energy than a supernova caused the phenomena. I presume that the process they're talking about is the decay of WIMPs and other dark matter candidates. The dark matter its self hasn't been directly detected unless you're counting this paper as an example of the contrary. The problem is that this is a very new paper in arxiv and as such requires much more peer review before we can say with reasonable confidence that their claim is plausible or not.
Re:Explanation Impossible (Score:3, Insightful)
That's just not a logical conclusion. It leaves out the much more likely answer that our understanding of the equations of motion is wrong.
So, you take a WHOLE YEAR of Physics in school, and suddenly, you are ready to say with confidence that all the formulas of physics (which, coincidentally, are correct enough to land a robot on Mars and propel a satellite out past the Solar System) are wrong?!?!? Further, you even state that it's MORE LIKELY that they are wrong?
You and your friend were astute enough to notice that you were using overly simplified formulas in your (first year) physics class. You don't think that maybe it's (ahem) more likely that you were just being introduced to the basic concepts, and the formulas were simplified a bit so that students could grasp it? Oooh! ooh! I took a class in this once!
Try really explaining a firewall to somebody sometime - you know, the protocol number, the port number, the IP address, the Mac address - or maybe you don't know, either? Well, many people think they know what a firewall is because they managed to get one to work with the web-based router interface. But how much credence would you give an IT guy who says blithely that setting up firewalls is inherently broken and that we need to rebuild everything, because of flaws he saw in the simplified web-based router interface?
Personally, I think you should pursue physics some more! See what the real formulas are when they start talking about the higher level stuff.... Of course, if you just want to use your 1 year to say "aw, they are all idiots because I took a class!" then so be it.
Just don't expect me to think much of your opinion.
Re:Explanation Impossible (Score:5, Insightful)
This is more along the lines of "our equations don't explain the observed motion of galaxies, therefore, there's matter there we can't see or touch."
Wow! I never thought they would do things like that! I would have expected things to go like this:
"our equations don't explain the observed motion of galaxies, therefore, it's reasonable to hypothesize that there's matter there we can't see or touch, let's test it."
And then they'd go and look for evidence or something. Thanks for correcting me!
That's just not a logical conclusion. It leaves out the much more likely answer that our understanding of the equations of motion is wrong.
So all that stuff I heard about MOND [wikipedia.org] was just in my head? Thanks for grounding me in reality!
Most galaxy motion simulations are based on either Newtonian mechanics or "modified Newtonian" mechanics, even though both are known to be wrong. Einstein showed them to be wrong over a hundred years ago!
You're right! It's quite likely that thousands and thousands of astrophysicists have spent decades researching a problem that has such an obvious solution. You're a veritable font of wisdom!
I studied physics at University, and both me and a friend of mine noted during our studies that Physics seems to overuse simplified equations ... Those simple equations are the ones we learned about also. They're wrong. In many practical cases, the error can exceed 30%!
O M G ! - W T F ! Low level physics classes use lots of simplifications? That explains why I can't find massless ropes and frictionless pulleys on E-Bay!
Re:Call me an astrophysics noob, but (Score:2, Insightful)
because you're an astrophysics noob and don't realize that blackholes do not explain it at all.
Re:Explanation Very Possible (Score:3, Insightful)
"When we add the Dark Matter fudge factor, our equations tend to get better, and we haven't found many (if any) equations that break in major bad ways because of it so, we will build our next bridge using this fudge factor and be confident it will be the best inter-galactic bridge built in 2009."
To see what engineers have to deal with on a daily basis, have a look at any of the links off of this page: lmnoeng.com [lmnoeng.com]. All looks very civilized and mathematical until you look further down each sub-page and see how conditional & fractional & empirical it all is. But it is the best we have and we manage to build with it. It is very obvious to geers that these are not final exact equations. These are just answers that work, and we work 'em.
Re:It's a black hole! (Score:2, Insightful)
Anytime your theory doesn't add up, or fails to predict the results of a new observation, why go through all the trouble of considering your theory falsified, questioning your premises, and coming up with new ideas?
Because every other scientist will laugh at you?
The more I see this kind of thing, the more I believe that mainstream science did not eliminate the priesthood. It merely replaced it with a more rational one to fit the changing needs of the people.
Yeah, creationists say the same thing. It seems to be amazingly common for dimwitted people to confuse their ignorance with "problems with science".
Re:It's a black hole! (Score:5, Insightful)
You want scientists to consider their theories falsified, question their premises, and come up with new ideas, eh? OK, when I find that galactic rotation curves don't line up with what I've predicted, I'll consider my theories (standard model with, as best we can manage, general relativity) falsified. I'll question my premises (for instance, the premise that I know exactly what particles exist in the universe). I'll come up with some new ideas (for instance, that there might be some type of particle that I don't know about). Looks OK so far, right? At what point do you have an objection to this?
One objection that I can see is that you might think that no other avenues of investigation have been explored. However, they have. Instead of questioning the standard model (giving us dark matter), we could question general relativity. This gives us a theory called MOND. It doesn't really work very well, but a lot of very smart people spent a great deal of time and effort investigating it.
In the end, in order to be a good scientist, you've got to come full circle. You take all the new ideas (new theories) that you've come up with, and you make predictions with them. Turns out that dark matter predicts something different from, say, MOND for a collision between two galaxy clusters which contain gas, stars, and dark matter. Well, we found such a collision (Bullet Cluster), and dark matter made the correct prediction, whereas MOND made the wrong prediction.
But that's not all. When you start to enumerate all the properties that dark matter ought to have in order to fit what we've observed in galactic rotation curves, the bullet cluster, etc, it turns out that there are not too many different ways in which to fit dark matter onto the standard model. And those ways in general predict different things about what astroparticle experiments like Fermi, ICECUBE, etc should see. Give it a few (~10) years, and these experiments will either have indirectly observed dark matter (and the characteristics of that observation will narrow down the particular type of dark matter dramatically), or they will have ruled out a large number of the candidate dark matter models, leaving even fewer. Give it long enough, and we'll have either made the indirect observation or ruled out all the models.
If we rule out all the models, then it's back to the drawing board. We'd have a falsified theory, we'd question our premises, and we'd come up with some new ideas. But until then, dark matter is a very good avenue for investigation. You shouldn't "believe" in it until it's been observed, but neither should you claim it's bad science. It isn't.
FWIW, I don't really expect to convince you of this, as you seem to be quite firmly decided that it is bad science, even though it fits your apparent criteria for what science should be. But hopefully I can prevent others who read both of our comments from being infected by you.
Re:It's a black hole! (Score:3, Insightful)
No, "dark matter" and "dark energy" are just discrepancies in two particular aspects of astrophysics. Empirical observations suggest that there's more matter out there than we can see. However, because they sound vague and they're active areas of research (that is, they're mentioned often and it's clear we don't know what they are), people who have no real understanding of physics jump to the conclusion that it's some general hand-waving. Perhaps this makes them reinforces their belief that they're so much smarter than those durned scientists -- who knows.
Re:It's a black hole! (Score:3, Insightful)
If you want to troll about how "mainstream science" is like some kind of cult pick an area of research that is'nt backed up with excellent experimental observation.