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Dark Matter Exists
olclops writes "It's a big day for astrophysics. After much speculation, scientists now have conclusive proof of dark matter. This result doesn't rule out alternate gravity theories like MOND, but it does mean those theories will have to account for exotic forms of dark matter."
"A universe that's dominated by dark stuff seems preposterous"
But not as preposterous as the "Big Bang". Imagine all the matter of the universe compressed to the size of an electron. Well that is a fabulous explanation for observations. Any other ideas?
Funny, I always figured the announcement of experimental confirmation of dark matter would first be published in a scientific journal or announced at a news conference...not on a blog shared by Mark, Claire, and Sean, whoever they may be.
* Note that I tried to go back and confirm the names and finish reading the story so I would have something intelligent to say, but apparently the user's CPU allottment only accounts for 20% of the server's total, suggesting that there may be another form of CPU cycles that don't interact with visitor's to the linked site. I think we should call these "dark CPU cycles."
...just supposition. After reading all this, all I see is that dark matter, which cannot be observed by any means other than gravitational effects on other non-dark-matter matter and seems suspiciously absent from everyday experience and experiment here on Earth, must exist because we think we see mass and energy behaving in a way that goes with our theories, yet we've seen it behave that way before and it is only in recent times we've decided that something is wrong with physics and we need dark matter.
Can anyone say aether? I knew you'd try...
We have next to zero understanding of the quantum vacuum, and don't know for certain if everything should pop in and out there including not only electrons and photons, but antiprotons and neutral pi mesons and everything else too. We do know it exists from many many Earth-side experiments and reams of dead trees covered in equations. We don't know how the potential fields exist which give rise to the fields we know, we don't know how any of them link in all ways to the nuclear fields which we also don't understand too well but we have loads of equations and experiments for those.
So we invent something, call it "dark matter", and look for anything we can then say matches our thought experiments and we can forgo all the careful Earth-side experiments. We just sort of treat the absence of any dark matter here or anywhere near here as one of those Hitchhiker's Guide SEPs.
More science-by-supposition and proof-by-spectacle. Show me the proof. Show me why dark matter has to exist. Prove it out with careful calculation and application to everything across the board. We've set off fifty megaton nukes for crying out loud without a single sign of anything amiss that would suggest we have a giant hole in physics requiring dark matter. We've done experiments on electromagnetic fundamentals, nuclear forces, and so on and along the way, we didn't hear of a need to invent dark matter.
But some people look at the cosmos and decide that despite not truly understanding the whole picture of physics at every scale yet, we can claim that dark matter exists and here's proof. Where in the Nine Hells does this stuff fit with the physics theories they alread promulgate as accepted science to be taught in universities?
It looks like modern aether, and it looks as though anyone buying it will be upset when someone working right along on the regular investigations into quantum physics and spacetime and so on puts it together and says, "oh, here's why that galaxy moves that way. We didn't need dark matter after all..."
If my grammar and spelling are off, I am [distracted/tired/careless] (take your pick)
Indeed, there is no such thing as "proof" in science. Merely observations that support a current theory. I guess "we observed phenomena consistent with a theory that claims dark matter's existence" even less headline-worthy.
E pluribus unum
We know nothing, and yet you can post bitchy comments to slashdot, on a computer, connected to the Internet, powered by a physical plant hundreds or thousands of miles away piping electricity directly into your laptop, and then watch a show on TV over cable distributed by satellite.
I'd hazard a guess that we actually do know a thing or two.
Anyone who loves or hates any language, platform, or manufacturer, doesn't know what they're talking about.
From the title - "This result doesn't rule out alternate gravity theories like MOND". Actually, this directly rules out MOND. That's a big part of the point of the experiment.The idea is that the mass in these clusters doesn't come from the obvious sources of visible matter (the gas), as it would in a MOND or normal gravity scenario, but rather from the invisible (i.e., dark) matter.
Kanye West is about as useful as used toilet paper.
Remember Vulcan, the planet with an orbit inside of Mercury? It was PROVEN to exist in the late 1800s. The calculations showed that Mercury's orbit required a smaller planet to make Mercury's orbit precess as it did. People even went looking for it with the finest telescopes of the day. And they saw it.
Then some smart aleck who worked in a patent office came along and showed that space is warped and that Mercury's orbit fits perfectly. Vulcan disappeared, never to be seen again.
Vulcan had more data in favor of its existence back then than dark matter does now. Pardon me, but I'm as skeptical as parent.
observed phenomena consistent with a theory that claims dark matter's existence
Or "evidence," for short.
https://www.eff.org/https-everywhere
Impact factor isn't everything. A factor of 5-6 isn't half bad - and certainly doesn't qualify the journal to the description "obscure"! Perhaps they wanted to publish this for their audience, and not for the more general audience of Nature or Science.
We see a certain amount of matter in the system. We see the gravitational effects of much more than that. So we have a premise that we see everything with an appreciable mass; that is disproven by our observation of gravitational effects that differ significantly from that which we predicted via the observable matter.
So, our options are to believe that some matter is disproportionately heavy than its appearance would suggest, or to believe that there's matter that we aren't seeing.
Did anyone else notice the amazing quality of TFA? I actually understand more about dark matter from that article than from anything else I have read on the subject to date. This makes me less grumpy about all the money I felt was "wasted" on telescopes vs. planetary exploration.
Quidquid latine dictum sit, altum viditur.
If you drop acid while reading the man page for 'fork', you too can write drivel like this.
Actually I think particle physicists are happy there's all this exotic unknown matter floating out there. Most modern particle theories practically scream for there to be (as of yet undiscovered) supersymmetric partners of all known particles. If dark matter turns out to be SUSY particles that would be a great experimental confirmation. If I had to bet, that would be my guess as to what dark matter will turn out to be. The great thing about science is there's always something unexpected around the corner, it would be really boring if we knew everything already.
You can prove things in math. Math isn't science. Math is a special construct where you make a few assumptions and then spend eternity figuring out what the consequences of those assumptions are. Thus, when you prove something in math you're really saying that X is always true assuming your axioms.
In science you don't get to make up the axioms. The universe does and we get to try to figure out what they are.
The fact that your mind thinks MONDian theories are more reasonable is irrelevant. MOND theory says while the force of gravity is different at galactic distances, it is still centered at baryonic matter. This observation shows the center of gravity NOT at baryonic matter.
It takes many many instances of evidence to give weight to a theory. It only takes 1 failure to disprove it. This is it for MONDian as we know it.
No, it's not the spiral structure of the galaxies that is problematic, it's the uniform motion of the stars themselves that is the puzzle. The two types of motion are different.
If I recall my astrophysics correctly, the arms of a spiral galaxy are somewhat akin to a wave phenomenon. The individual stars revolve around the galactic center far more quickly than the arms themselves move, so the stars actually enter, pass through, and leave each arm as they circle the center. The arms arise because the stars tend to loiter there longer than in the spaces between the arms... a result of the gravitational attraction of the other stars congregating temporarily in that arm.
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As for the topic at hand, I have to say it really bugs me when science reporters claim that some new evidence "proves" such and such a theory. This isn't pure math, and it isn't theology either; stop hanging on to comfortable notions of being able to "prove" this or that theory as if to end the debate. One of the glories of science is that it is a work in progress, with precious few certainties.
Procrastination Man strikes again!
My own argument against MOND and suchlike gravity mods is that they are totally ad-hoc. Modifying gravity is nice, but to be convincing it would be better to come up with beliveable first principles from which such a modified theory would emerge, rather than adding random free parameters with no basis in reality.