Hubble Telescope Maps Dark Matter in 3D 174
dido writes "The BBC reports that the Hubble Space Telescope has been used to make a map of the dark matter distribution of the universe, providing the best evidence of the role dark matter plays in the structure and evolution of the universe. From the article: 'According to one researcher, the findings provide "beautiful confirmation" of standard theories to explain how structures in the Universe evolved over billions of years.'"
And yet... (Score:1, Funny)
*bitter*
you can't stop the spin machine (Score:5, Funny)
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Oh God, why do you Slashdotters always have to start talking about religion or politics whenever we get an article about science?
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You must be new here...
...
If I was new here I couldn't yet have noticed the recurrence of comments about religion and politics when come the science related articles. I complain about it because I've noticed it for quite a while and am getting tired of it.
And while you're much older than me here I'm the one with the excellent karma lol.
This is pretty cool. (Score:3, Interesting)
Re:This is pretty cool. (Score:4, Funny)
Maybe I've just been around here for too long, but the parent post reads like goatse.cx meets GNAA.
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In reality you have to get within a few thousand kilometers of the event horizon for you to notice anything peculiar. Further away and the gravity well looks and behaves almost identical to an ordinary star.
Black holes doesn't play any role in the distribution of cosmological dark matter
Does Dark Matter exist? (Score:1)
Re:Does Dark Matter exist? (Score:5, Funny)
That's dark matter.
I think that should be a modifier. -1, Dark Matter
Don't be mad that you didn't think of it...
Re:Does Dark Matter exist? (Score:5, Informative)
Astronomers have ways to measure the mass of objects, like galaxies, and cluster of galaxies, using a theory of the gravitation. For galaxies, the classical newtonian theory is enough: they just measure how fast the stars and the gas orbit around the galaxy, and derive directly their mass from kepler laws. For clusters of galaxies, or large structure, they use the bending of light by mass from general relativity. These measure are getting reasonably accurate. When they compare these masses to the mass they actually can see (stars, gas, etc..), they find that they can only account for 1/6 of the total mass they measure, well above all the uncertainties of the measurments. Therefore, there must be some matter (that is, something with a mass), that we cannot see (that does not interact via electromagnetism). This is the dark matter.
For more info, there is a [wikipedia] [wikipedia.org] entry.
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This is what I don't get about dark matter, and this is just how I see it, and no one has ever given me a decent explanation. Why is it that scientists think that dark matter exists simply because the observed galaxies don't conform to Newton's Laws? Wouldn't a simpler solution be to take a step back and consider that, maybe, Newton's Laws are flawed? I am not trying to disprove dark matter, I certainly am no cosmologist, but it just seems odd that so much attention is given to dark matter, and very litt
Re:Does Dark Matter exist? (Score:4, Informative)
Dark matter == epicycles? (Score:3, Insightful)
Some skepticism is certainly in order. Since we currently have no way of independently confirming the existence of dark matter, we also have no way of distinguishing between two possible cases: one case is that dark matter corresponds to some real, physical material; the other is that the theory of gravity we're using is flawed. The fact that a better theory of gravity hasn't been produced doesn't mean that the current one is correct.
There are pretty st
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Since we currently have no way of independently confirming the existence of dark matter, we also have no way of distinguishing between two possible cases: one case is that dark matter corresponds to some real, physical material; the other is that the theory of gravity we're using is flawed.
No one has actually succeeded in producing a modified gravity theory that can mimic the effects of dark matter. It is not true a priori that this can be done; there are a lot of constraints on both the possibilities for dark matter and the possibilities for a gravitational theory, and they don't necessarily intersect.
There are pretty strong parallels between dark matter and the infamous epicycles.
Dark matter is not like epicycles. Epicycles are essentially a Fourier expansion of any orbital motion, and as such, they are totally non-predictive and unfalsifiable. Dark matter theories
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"Whatever result we want" is true as far as it needs to be, in this situation. The situation is that we can observe a certain amount of mass via various means, but it doesn't behave according to the theory of gravity that we think ought to apply. So one question is whe
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You repeatedly raise the issue of my dismissing evidence as though it counts for nothing. What I'm actually attempting to say is that given a lack of independent confirmation via some other means than gravitional inference, dark matter is on less firm ground than many theories in other areas of physics and astrophysics. This is the grounds for (healthy) skepticism about dark matter that I originally suggested. The way I read your position, you seem to be denying that dark matter has any such weaknesses.
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What I'm actually attempting to say is that given a lack of independent confirmation via some other means than gravitional inference, dark matter is on less firm ground than many theories in other areas of physics and astrophysics.
I will agree that it's on "less firm ground than many theories in other areas of physics and astrophysics", but I disagree that the evidence for dark matter is weak. It is, by now, quite strong, even if it is indirect.
What would strengthen the case for dark matter is a model in which the gravitationally inferred quantities of dark matter match amounts arrived at by other means, for example.
Yes, it would strengthen the case for dark matter even more, but the mere existence of a wide variety of plausible dark matter candidates within frontier particle physics has already strengthened the case for dark matter beyond just astrophysical evidence.
Do you have any evidence to support this supposition?
You can't prove it, but it's basic
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You mean, apart from the fact that you need to create 90+ percent more matter in the universe than what is visible to prevent galaxies from flying apart?
i.e. without dark matter (and dark energy), gravity doesn't predict much.
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These findings probe dark matter existence. (Score:2)
They actually mapped it.
On 3D!
If it was a hack, it would be one of the cleverest, more accurate hacks in the history of science.
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Dark matter is a crutch of a theory with so many problems they had to invent an imaginary substance to explain them.
The history of science is filled with examples of new particles that were predicted — and discovered — on the basis of experimental discrepancies. You're going to have to do better than that.
The term "dark matter" originally referred to normal matter that we couldn't see because it wasn't lit up. Once this idea was proven inadequate, dark matter became something new and its definition was shaped solely by what the theorists needed it to be.
You say that like it's a bad thing. Theories that don't work are replaced by theories that do.
But even with these inventions, they are routinely surprised by what they find in the universe.
So? Nobody has claimed that we know everything about the universe. Dark matter and dark energy are features of our universe, but they don't explain everything about it.
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Well, most of science has yet to agree what it is, but Randy Mills has a pretty solid theory backed by observations. [blacklightpower.com]
Mainstream says the 10% of the universe that is observable is 90% hyrogen, 9% helium, and 1% everything else. Mills says that the 90% unobservable universe is a lower-state hydrogen atom that he calls a "hydrino". The Mills theory explains the answers to some very old scientific questions, such as 'what happens to a phot
Re:Does Dark Matter exist? (Score:4, Interesting)
Some time ago, a man named Hannes Alfven, who is today considered the father of plasma physics, founded the field of magnetohydrodynamics, which astrophysicists have been using to model plasma in the universe for several decades now. This field treats plasma as a fluid and assumes that currents cannot flow through the plasma because it treats plasma as an ideal conductor with no resistance. This is actually not *anything* like the way that plasma operates in the real world, and since plasma represents 99%+ of all observable matter within the universe, this massively incorrect assumption yields absurd results in astrophysics today. Plasma is in fact electrically conductive and its electrical properties interact with its mechanical motions, and vice-versa. If you've ever seen a novelty plasma globe, then you intuitively know that plasma is not like a fluid. You can tell by looking closely at a plasma globe that the plasma creates filaments and these filaments pair up and twist around one another. These twisting currents are called Birkeland Currents. As the current flow increases through them, they pinch together with increasing force and this pinching action can actually condense matter into a ball. This is a big deal because there is no good reason to believe that molecules will gravitationally collapse from a diffuse collection of matter in space; in fact, gases obviously expand in a vacuum. Contrary to the more popular beliefs propagated in astrophysics and the media today, the z-pinch effect is likely actually how planets and stars form. Astrophysicists don't understand this because of their earlier assumptions regarding plasma being a fluid with no currents. But we can see strong evidence of Birkeland Currents and Z-Pinches happening through our telescopes.
The thing is, astrophysicists will see what they want to see through the telescope. All observations today are interpreted through mainstream concepts like stellar evolution and Big Bang theory. When an anomaly pops up, it can be a very simple matter to propose a "patch" for the theory to keep it going. Astrophysicists will invoke collisions, black holes, gravitational lensing or malformed electrical theory in order to explain away anomalies. But you will notice that anomalies are discovered nearly every week these days (especially with stellar evolution), and this is a problem because things like collisions should not actually be happening as often as they are being invoked to dismiss the anomalies.
When Hannes Alfven received his nobel prize for plasma physics in the 70's, he recused himself from the field that he created (MHD) and warned astrophysicists to abandon it, and that the path they were taking would eventually dead-end. But they completely ignored him and continue to do so. So, now we have mysterious forces tugging on matter throughout the universe that we can't see. This is what we call dark matter. Dark energy is supposed to be matter that can gravitationally repel. Electrical forces can accomplish both of these feats without any mysterious matter. All you have to do is drop the earlier incorrect assumptions about plasma and accept that extremely diffuse plasma flows can and do exist. You will notice over time that the dark matter studies will reveal some details that correspond with the properties of electricity over plasma. For this particular article, it was noticed that the structure of the dark matter was in places filamentary. Filamentary structures are far easier to generate with electricity than with gravity. It was also mentioned that dark matter can exist in the absence of physical matter. This is to be expected with plasma because plasma can consist of just electrons and ions, or it can also be coexisting with or collecting dust.
Some brave scientists and electrical engineers called Electric Universe Theorists are working on understanding the universe in terms of real plasma physics -- which makes p
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I'm have flashbacks of sci.physics and Petr Beckman...
-JS
Holly cow... (Score:2)
On 3D.
How do you explain that?
Enlighten me (Score:4, Interesting)
Re:Enlighten me (Score:5, Informative)
Some portion of it could be ordinary matter that's simply non-luminous, but I think there are observations that limit that to a small proportion.
The rest seems to be something that interacts only gravitationally... it might be a particle we haven't discovered yet. That's not as far fetched as it sounds -- neutrinos are just such a particle. They have mass so they interact gravitationally but they interact with ordinary matter extremely weakly in all other ways. Massive neutrinos were also candidates to explain some of the dark matter for a while, but I believe once their actual mass was measured it was too little to explain more than a bit of the dark matter.
Re:Enlighten me (Score:5, Informative)
See also http://en.wikipedia.org/wiki/Brane_cosmology [wikipedia.org] .
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Re:Enlighten me (Score:5, Funny)
Yeah, but string theorists make theoretical physicists look like scientists
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This is actually made a much less tenable theory by the latest gravitational lensing result involving colliding galaxies. Presumably matter on an adjacent brane would interact with itself other than gravitationally, but it's clear from the lensing that the dark matter didn't interact with itself other than gravitationally.
Perhaps the laws of physics are different on the other brane, but it still seems odd that the two bunches of matter would pass right through eachother.
Well, there could be two adjacent
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Is there any chance that there's two classes of graviton? Like the electromagnetic force has attract opposite, repel like. Could the gravitational force which has some similarities to the electromagnetic force have attract like, repel opposite.
That would require a vector theory of gravity. General relativity is a tensor theory. There are combined tensor-vector theories that have features of both, as you suggest. But there is no observational evidence in their favor right now.
And while I'm at it, is it possible stuff escapes black holes because passing matter causes small changes in the gravitational field hence shifting the event horizon and causing the photons that are orbiting near the event horizon to escape orbit.
No. An event horizon, by definition, is a region from which nothing can ever escape. The horizon of a black hole can distort, and something near a black hole can be perturbed away from it, but anything that escapes a black hole was never within the event horizon to beg
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ie. if a photon enters the event horizon at a shallow angle so it has not dropped below the event horizon by very much, then the event horizon is perturbed by a large mass passing close to the black hole, would the photon escape again? And if not, why not?
No, it would not escape, because as I said, an event horizon is defined to be a region from which nothing ever escapes. To precisely locate it, you have to know everything about what will happen in the vicinity of the black hole, including everything that will perturb it at any time in the future — only then can you tell which objects will or will not eventually be able to escape.
In many respects, that makes an "event horizon" a very difficult concept to work with, and it means that you can't actual
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It is possible that most of the dark matter needed by current theories to explain the universe we see doesn't really exist, and that our understanding of gravity is wrong. The TeVeS theory, developed from MOND, may be able to explain the universe without requiring that most of it be made of dark matter and dark energy. See Gravity's dark side [physicsweb.org]. Also mentioned in a previous Slashdot stor [slashdot.org]
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Even without those, as you said, modifying gravity might explain most of the observations. That still leaves some others, that we'd need something else to explain. Even the modified gravity researchers are saying ou still need some dark matter to make everything work.
So, Occam's razor -- which is the simplest explanat
Re:Enlighten me (Score:5, Informative)
Big Bang nucleosynthesis limits the amount of baryonic (that is, "normal") matter to a relatively small fraction of the total observed mass of the universe. The basic idea is that we know how big the universe was when protons and neutrons (collectively known as nucleons) were being formed--at some point the cosmic fireball cooled off to the point where quarks were no longer free, so they condensed into nucleons. We also know that the lifetime of a free neutron is about 15 minutes, so there was only about an hour for nuclei more complex than hydrogen to form.
So, if the universe was VERY dense in the hour or so after nucleon formation then every single proton would have run into a neutron or two and there would be almost no plain old hydrogen in the universe--everything would be helium and deuterium. On the other hand, if the the universe were extremely diffuse during that single hour there would be hardly any helium--only the few percent made by stellar fusion and supernova in the past ten billion years. As it is, we are pretty sure based on observations and theory that about 20% of the helium in the universe was formed in the Big Bang. That, plus some more problematic numbers from deuterium and lithium and helium-3, give us a very good estimate of the total baryonic mass in the universe.
The visible mass is quite a bit smaller than the total baryonic mass, and there is some reason to believe that the flat rotation curves of spiral galaxies are due to baryonic dark matter, although it would have to be in the form of small clumps of matter like comets or dead stars or something to not do any significant scattering of light.
Dark matter on larger scales is completely unrelated to galactic dark matter--the use of the single term "dark matter" for these totally unrelated problems is unfortunate and confusing, as I point out every time this topic comes up on
The observation reported here, like the colliding galactic clusters observation reported a month or so ago, is amongst our first clear view of extra-galactic dark matter, which is too copious to be explained as normal baryonic matter.
The problem that cold dark matter theorists have to deal with is that the extra-galactic dark matter can't just interact gravitationally, because gravity is too weak a force to produce structures in the short time the universe has been around. To clump in the manner observed, extra-galactic dark matter has to have some mechanism for losing energy. Otherwise two pieces of dark matter (or a piece of dark matter and a peice of ordinary matter) would just pass through each other. The dark matter would never be slowed down by anything, and so would never form clumps on any scale.
So it is probable that extra-galactic dark matter is pretty exotic, or that something was sufficiently different in the early universe to make gravity sufficiently dissipative to form the observed clumps. Either way, the flood of observations using these new microlensing techniques is going to start killing off theories in droves--at least those theories that make actual predictions.
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DM does not exist in galaxies. (Score:2)
See http://www.astro.umd.edu/~ssm/mond/ [umd.edu] for further information on MOND.
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Damned facts, always getting in the way.
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I fail to see how it is a "poor excuse" for anything, it's mearly a description of something we don't fully undersatnd but can indirectly observe and therfore label. Maybe our elegant theories will need to change to account for future observation but right now our notion of what we label as "dark matter" explains the observed a
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Funny how that statement proves you are an AC wanker, but I suppose that's not important.
Re:Enlighten me (Score:4, Informative)
There are a wide variety of dark matter searches being conducted which directly search for the particle. The general idea is to see their interaction through the recoil of an atom when one strikes the atom's nucleus. This is very difficult. The most common current technique is searching for the "sound" a dark matter particle interacting with cryogenically cooled germanium crystals produces.
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It strikes me as a wishful-thinking fiction more than a testable, observable phenomenon.
-Eric
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If everything was visible the night sky would be bright instead of dark.
The illumination must be bright enough that we can see it at distance - its like us trying to see the lights onboard the ISS.
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dark matter does not exist (Score:3, Insightful)
What standard theories? Dark matter does not exist, as least not as far as anyone (except astronomers with good imaginations) knows. There is a very nice (and complete!) standard model of physics, and dark matter holds no place.
I should qualify, I'm talking about theroes of non-baryonic dark matter [wikipedia.org] and even worse dark energy [wikipedia.org].
Regular matter, that is simply dark - i.e. cold, and not emiting light, does not bother me. But making up particles no one has ever seen just because you don't understand what you are seing is fitting facts to the data.
Scientists often discuss new theories, etc, and in that context dark matter has it's place, but to claim it exists - as this story does - without being able to actually measure anything is quite silly and premature. If you don't understand something, say so, don't invent plausable explanations that have nothing supporting them except your lack of knowledge.
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Re:dark matter does not exist (Score:5, Insightful)
Re:dark matter does not exist (Score:5, Informative)
- 70% of dark energy
- 30% of matter
- out which, stars, gas, neutrino are making at most 5%
- so we are left with 25% of dark matter
So yes, dark matter is widely accepted. It's not satisfying because we have no clue about what it is (it clearly does not interact electromagnetically), but we can feel its gravitational pull. Coming up with a good theory on its nature is one of the hardest challenges in modern astrophysics.Re: (Score:2, Insightful)
I smell a Thomas Kuhn moment in the making. Or at least, a phlogiston moment.
Explaining the universe is hard. But saying stuff like "it's real", even implying that it is
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70% of the universe is made of some theoretical "substance" that hasn't shown up in several decades of particle physics observations??
Why should it, if it's weakly interacting and massive? (Which are precisely the properties it needs to explain the astrophysical observations, by the way.)
I smell a Thomas Kuhn moment in the making. Or at least, a phlogiston moment.
The difference is that dark matter keeps on passing new and independent observational tests.
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You do realize that science is 'just' fitting theoretical models to data, do you? And that, while a model survives by being able to fit more types of data, it usually starts by fitting one or a handful?
Scientists often discuss new theories, etc, and in that context dark matter has it's place, but to claim it exists - as this story does - without being able to actually measure anythi
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Because galaxies don't rotate the way our current theory of gravity says they should, because gravitational lensing isn't working the way our current theory of gravity says it should, because of a bynch of other thing I guess, the accepted solution it to declare that 95% of the universe is made of stuff we can't directly detect, can't do experiments on, doesn't exist locally, and is completely different from the universe we do obse
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Because galaxies don't rotate the way our current theory of gravity says they should, because gravitational lensing isn't working the way our current theory of gravity says it should, because of a bynch of other thing I guess,
You act as if having a bunch of observational evidence for dark matter is unimportant.
the accepted solution it to declare that 95% of the universe is made of stuff we can't directly detect,
Would dark matter be more palatable to you if it only made up 5% of the universe? Why does it suddenly become more implausible if it makes up most of the universe. It's because it makes up most of the universe that we can even tell it's there.
can't do experiments on,
That remains to be seen; we may be able to create such particles in accelerators, and we may also be able to detect them in the Sun, in cosmic ray experiments, etc.
That being sai
Re:dark matter does not exist (Score:5, Informative)
Sure, everyone would love it if we could detect dark matter particles directly — and if they interact non-gravitationally, we hopefully will someday. But what's silly is to claim that we have little reason to believe that dark matter particles exist.
Standard Model Complete... With Caveats (Score:2)
There's also the unresolved matter of actually observing a little particle that is in the Standard Model called the Higgs boson.
Trust me, the standard model is really really good, but it's far from complete.
Re:dark matter does not exist (Score:5, Informative)
So let's start at the beginning, shall we? Galaxy rotation curves indicate that there is more mass in galaxies than would be inferred from the luminous matter. How do we know that it's not clouds of cold gas? Because that's ruled out by 21cm observations and by studying the absorption spectra of extragalactic objects. How do know that it's not clouds of hot gas? Becasue that's ruled out by UV and X-ray observations. How do we know that it's not brown dwarfs and black holes? Because that's ruled out by microlensing surveys.
Now, studies of galaxy dispersion velocities in clusters indicates that there's more mass in galaxy clusters than than would be inferred from the galaxies themselves, plus the intracluster medium which is observed in the X-ray. This is verified to high accuracy (i.e., the estimates of the total cluster mass are in close agreement) by hydrostatic X-ray mass measurements and by weak lensing observations. How do we know that it's not clouds of cold gas? Because that couldn't coexist with the hot gas, and because the dark matter spatial distributions are clearly different from the gas distributions. How do we know that it's not clouds of hot gas? See "intracluster medium" above. How do we know that it's not brown dwarfs and black holes? Because there's no mechanism for moving large numbers of objects out of the galaxies into the ICM (there are some intracluster stars, yes, but relatively very few--and the number of those gives us hints as to the number of non-luminous objects similarly ejected). How do we know that it's not neutrinos? Because neutrinos are experimentally shown to be too light and too fast, and cosmological constraints show that too few would have been produced in the Big Bang.
Now, studies of cosmological structure formation indicate that the size and number of galaxy clusters in the universe are not consistent with what would be expected given an all-baryonic universe. How do we know that...er...well, that's that. Cold collisionless dark matter is required to make the simulations work.
How do we know that modified gravity isn't the answer? See multiple independent lines of evidence above. There are no theories of modified gravity that come even close to explaining all of the above. The MOND people cheerfully acknowledge this, even if their advocates on Slashdot don't.
Look, the history of physics is replete with things whose existence was inferred long before they could be directly observed--neutrinos, quarks, atoms themselves, and much, much more. It's simply asinine to suggest that "we haven't directly measured it" means "it doesn't exist". Heck, we only really "see" subatomic particles because of the photons given off when they interact with one thing or another--"seeing" dark matter via measurements of its gravitational effects is hardly less direct.
And we'll just ignore the nonsensical "fitting facts to the data". The bottom line is, there are multiple, independent lines of evidence that dark matter exists, and that it is non-baryonic. Uninformed posters on Slashdot can pat themselves on the back for their intelligence as much as they want, but they're only fooling themselves.
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True. Nothing can really provide better answers than saying god does everything. Fact is that Dark Matter and Dark Energy are not falsifiable theories. They can only be proven true, by finding the so called dark matter, but cannot be proven false by any means.
The best Dark Matter theories require 2 parameters
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That said, as the universe is explored in more detail, we increasingly see that the standard model is robust but has some issues, in the same way that mor
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On one level, I consider dark matter to have the same credibility as the æther. An interesting concept, but largely created as hack to the model.
Aether theories didn't make any predictions that correctly explained any new observations. Dark matter does.
Certain unexplained acceleration in the cosmos has renwed interest in the Einstein cosmological constant, which if it exists, renews the presence of the æther, albeit in a different form.
The cosmological constant is a modification of the laws of gravitation, not anything like what was historically referred to as the aether.
Dismissing a concept simply because it is a mathematical hack is a mistake. In reality we use mathematics because it is a precise language that will often lead us to an unobserved reality.
This point is well taken. However,
Recall that special relativity is based on Einstein's assertion that equations should be symmetric.
That wasn't Einstein's motivation for introducing special relativity. (On the other hand, the complete form of Maxwell's equations of electromagnetism were based on Maxwell's assertion that the equations should be symmetric.)
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But talking about hypotheses as if they were solidly established theoretical constructs, dovetailing with the framework of well-established physics, does, IMHO, a disservice to science. For one thing, it tends to make it hard to see alternatives by freezing an attitude and blinkering the imagination needed to see alternatives. For another, it tends to make some laymen skeptical about *any* claims of science.
IIW, a hypothesis repeated
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The whole point of these observations is that they are an entirely new probe of extra-galactic dark matter, and they are consistent with dynamical estimates of extra-galactic dark matter distributions.
Ergo, they consistute compelling evidence that extra-galactic dark matter is not just a mistake
Hmmm... (Score:1)
Uh-oh! It just reached half-life! Nasa better hurry up and find this long lasting nuclear element before its lost forever. We wasted the first half of this universe's existance, lets not waste the second.
Oh wait...this statement would only be true if the universe was ending at exactly this moment and the hubble did this scan half-a-u
RTFA (Score:2, Insightful)
So this map is based on what they assume the universe should look like. Then they use how its different to find where the dark matter might be. Doesnt sound 100% certain by any means, but its a nice picture.
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Isotropy is an assumption, but we have never detected a significant deviation from isotr
Density Issues affecting the shape? (Score:2)
Seems to me there would be a wide range of density distributions. If so there must have been a human decision to decide
which level of density constitutes matter vs. empty space in this 3d depiction. I wonder how the 3d shape would change
if we arbitrarily moved this balance point of requisite density up or down the scale.
A Cool-Blue Model (Score:1)
I don't know how much weight this "dark matter" theory holds (pun intended). But I was immediately interested when I saw their translucent blue 3d render of the stuff.
I wonder how many other people that works for...
Politically incorrect (Score:1, Funny)
HubbleSite.org press release (Score:2)
I've tried to find something about whether this tells us something new about the properties of dark matter, but so far no luck. Anyone have a link to something more informative?
More links to PR (Score:1)
wtf is "dido"? (Score:2)
What's It Like, Other Than Dark? (Score:2)
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But what kind of matter doesn't interact with electromagnetics?
Any elementary particle that is electrically neutral.
Have we ever physically obtained any? Synthesized any?
If by "any" you mean "electromagnetically non-interacting", then there are neutrinos. If you mean "the kind of dark matter that is needed to account for astronomical observations", then no, we haven't.
And supposedly something like 70% of the dark "matter" is energy. How does non-dark energy interact with electromagnetism, where the dark "stuff" does not?
What is "non-dark energy"? Photons? I don't understand the question.
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Photons aren't energy, they're matter with an energy equivalence proportional to their frequency. Maybe the descriptions of "dark energy" are inaccurate - they're describing dark matter at high energy. Perhaps neutrinos, or some other non-interacting particle in motion. But dark energy [wikipedia.org] is described as different from famil
But I thought... (Score:2)
excellent.... (Score:3, Funny)
Re:"There's something out there" (Score:4, Funny)
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If that's your position
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Dark matter doesn't make a claim on one's life. The other replier who said, "dark matter doesn't damn you to hell for wanting to have sex", while wrong, illustrates this point. "If God doesn't want what I want then screw Him/Her/It/Them".
Re: myth about dark matter still out there .. (Score:2)
"Modified Newtonian Dynamics (MOND) is a theory that explains the galaxy rotation [wikipedia.org] problem without assuming the existence of dark matter"
"'Ether' retu