Hard Light Productions Forums
Off-Topic Discussion => General Discussion => Topic started by: Kosh on August 22, 2006, 04:29:49 am
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http://cosmicvariance.com/2006/08/21/dark-matter-exists/
WH0000000000000t!!!!!!!!!!!
The great accomplishment of late-twentieth-century cosmology was putting together a complete inventory of the universe. We can tell a story that fits all the known data, in which ordinary matter (every particle ever detected in any experiment) constitutes only about 5% of the energy of the universe, with 25% being dark matter and 70% being dark energy. The challenge for early-twenty-first-century cosmology will actually be to understand the nature of these mysterious dark components. A beautiful new result illuminating (if you will) the dark matter in galaxy cluster 1E 0657-56 is an important step in this direction. (Here’s the press release, and an article in the Chandra Chronicles.)
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Cosmic M&M's, man. i'm sure there's Green matter, red, blue, yellow, and so on.
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Cosmic M&M's, man. i'm sure there's Green matter, red, blue, yellow, and so on.
Yeah, but do the orange ones taste different?
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Cosmic M&M's, man. i'm sure there's Green matter, red, blue, yellow, and so on.
Yeah, but do the orange ones taste different?
they prolly taste like everything else....
Like Chicken.
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They didn't know what chicken tastes like, so they made everything taste like chicken......
:nervous:
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They didn't know what chicken tastes like, so they made everything taste like chicken......
:nervous:
'cept McD's burger patties... which tastes like cardboard..
Consequentially, cardboard tastes like chicken.
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nukes cosmic theory: the universe is made out of chicken :D
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Alas, it didn't come with any spice, or even a dip.
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But it sure did come fully equipped with more than sufficient amount of dip****s... :p
Joking aside, the terms are really really cool. Dark energy, dark matter... I wonder where they come up with this, it's almost as good as fictional techno-babble. Names for particles are another constant source of admiration. I wonder when they'll run out of Greek letters. Then they have a difficult decision to make. Whether to start naming particles at all or just numbering them. Or perhaps they start using Tolkien's elven writing marks...
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"Dark matter" isn't a technobabble name; it's a pragmatic one. The whole point of dark matter is that it isn't visible like other matter is, because dark matter only interacts with other matter through gravity.
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Woot, another leap in the forward direction for darkmatter. Now all we need to do is determine what the darkmatter actually IS, or at least some better theories/models to explain how it works. :)
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in truth, Dark matter is just like any other matter, only emo. :P
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Alas, it didn't come with any spice, or even a dip.
there is a dip but its in the dimentions beyond :D
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f3@r 7h3 1337 $p3@k3r$!(eleven)
(Be glad for easy-read 1337)
yep, it's just... matter. Or, it's gravitational disturbances appearing from nowhere...
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as far as my understanding of string theory goes, dark matter/energy exists in dimentions other than our own set of dimentions and that gravity trancends the dimentional boundries. to us gravity apears weaker than the other 3 forces in the universe. however all forces should be technically equal. if the force of gravity is being scattered and spread thin in extra dimentions, it wouild explain why gravity was weaker. dark matter being extra-dimentional, our only influence over it is through gravity. dark matter is probibly floating around your room right now and you wouldnt know it. but its gravity effects us, and ours affects it, i think.
the chicken theory makes more sence though :D
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They didn't know what chicken tastes like, so they made everything taste like chicken......
:nervous:
'cept McD's burger patties... which tastes like cardboard..
Consequentially, cardboard tastes like chicken.
those burgers are LIFESAVERS. I'd die if mcdonalds died...
mmm chicken!
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as far as my understanding of string theory goes, dark matter/energy exists in dimentions other than our own set of dimentions and that gravity trancends the dimentional boundries. to us gravity apears weaker than the other 3 forces in the universe. however all forces should be technically equal. if the force of gravity is being scattered and spread thin in extra dimentions, it wouild explain why gravity was weaker. dark matter being extra-dimentional, our only influence over it is through gravity. dark matter is probibly floating around your room right now and you wouldnt know it. but its gravity effects us, and ours affects it, i think.
That's the string theory explanation of it. Pretty intriguing, but no evidence of it yet though.
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It's definately there tho. and there is 5 times more non-baryonic matter as there is baryonic matter (us) :(
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The more I learn about it, the more skeptical of String Theory I become. If it made predictions that could actually be tested I'd take it more seriously. Otherwise, it really falls under the weight of Occam's razor. It is far too complicated an explanation. Quantum Electrodynamics is bad enough on its own, but it at least makes predictions that have been tested over and over again. Maybe it is naive of me, but my gut feeling is that the rules that govern the universe are actually quite simple. It is just the implications of those rules that are complicated. Take any simple set of rules, or even a single rule, and increase the population the rule acts on to a paltry billion and see how complicated that gets. As N -> infinity things get pretty mind boggling.
Anyway, one thing that does puzzle me for any of the astrophysicists out there: If there is so much dark matter out there, what keeps it from gathering up like stars? Why is it so diffuse? Further, if it did gather up like stars, what would stop it from collapsing into singularities? I mean, the only reason stars don't collapse is because of the outward pressure of radiation from fusion (ok, and degenerate electron pressure in the case of white dwarves etc.) Seriously. Any clues?
You know, if there is that much dark matter out there, it stands to reason that stars are probably forming where dark matter draws the necessary gas clouds. i.e., stars would be forming in the middle of clumps of dark matter. The point: what if most of the mass of stars isn't baryonic matter at all?
Gah. Sounds pretty fishy but I'm too tired to find the error(s) in my reasoning.
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perhaps dark matter uses a different time axis or follows different physical rules than we do. perhaps for every piece of matter in the univerce theyre could be another object in a similar space the dark dimentions. another possibility is cross-dimentional spacial asymetry. that is the dark mater spacial plane is distorted relitive to ours, there may be dark stars and planets out there, but it only apears diffuse to us because its distorted. but seeing as the only way we can see dark matter is through gravitiational lensing, there could be large clumps of dark mater out there that we cant even detect. so far all we can detect is diffuse clouds of dark gas on a galactic scale.
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Maybe it is naive of me, but my gut feeling is that the rules that govern the universe are actually quite simple. It is just the implications of those rules that are complicated.
Ah yes, the wonders of truthiness (http://en.wikipedia.org/wiki/Truthiness). ;)
I agree with you about String Theory. Evidence makes or breaks a theory. If you can't find evidence for it, it's just as useless as intelligent design. On the other hand, the Standard Model of particle physics is great. Hell, Quantum Electrodynamics is one of the most accurate models in all of physics. It'll be even better if the Higgs Boson is found by the Large Hadron Collider (http://en.wikipedia.org/wiki/Large_Hadron_Collider) that's due real soon. :)
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Does this mean now that we know it exists, we can start working on subspace drives and all that yet? :p
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Subspcae... bahh...
What we need is a quantum computer. Cubits already work (and it's now quite certain that the multiverse interpretation of quantum theory is at least more accurate than the Copenhagen interpretation).
Have any of you ever heard of beam splitters and photon interferences? The produce some really really weird phenomena. They are very interesting, even moreso than dark matter and all...
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no, we need to make an Anti-Higgs-Boson for that.
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I see darkmatter as the unseen filler. There has to be "something" in between atoms, if there was nothing.... well I really don't know what would happen, but I doubt the atom would win the fight.
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i myself think string theory has potential. however i also think that as we start understanding dark matter better it will eventually give us a means to test string theory once and for all. i dont think string theory should be cast aside just yet.
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in truth, Dark matter is just like any other matter, only emo. :P
Lol. Nice.
What's next? Shivans?
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I see darkmatter as the unseen filler. There has to be "something" in between atoms, if there was nothing.... well I really don't know what would happen, but I doubt the atom would win the fight.
There are electrical feilds between atoms.
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I see darkmatter as the unseen filler. There has to be "something" in between atoms, if there was nothing.... well I really don't know what would happen, but I doubt the atom would win the fight.
False reasoning. There does not 'have' to be anything. By what we know about the Universe at that scale, there is no reason why there should be anything between atoms except the forces keeping them seperate. Same goes for the internal structure of the atom; between the nucleus and the electron shells, there is (AFAWK) nothing except the carrier particles of the various forces that enforce that gap.
Dark matter is likely just another type of fermion with properties (spin, etc) that prohibit it from interacting with any particle other than the gravity carrier particle (assuming it exists). If gravity is not a carrier-mediated force, the definition of dark matter is simpler: it does not interact with any particle, but possesses mass.
As for Superstring being useless: not so. At present the predictions are untestable, but the model fits our current data (IIRC) making it at least as good as the standard model. Furthermore, the theory has shattered some preconceived ideas about the workings of the Universe; preconceived ideas when trying to find a Theory of Everything are not a good thing.
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Anyway, one thing that does puzzle me for any of the astrophysicists out there: If there is so much dark matter out there, what keeps it from gathering up like stars? Why is it so diffuse?
I do remember reading a theory somewhere that it's basically all neutrinos. Just lots and lots of neutrinos.
No idea how plausible that is though :)
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Since neutrinos may not even have mass, you're going to need a hell of a lot of them...
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it just occured to me if gravity trancends multile dimentions it may be possible the other 3 forces have diminished or no influence over the dark mater spatial plane. there may be other forces in the universe we dont even see. like if the dark mater doesnt posess a strong atomic force, it cant fuse as atoms and thus would only exist as loose particles.
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Like the land of wind and ghosts?
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Since neutrinos may not even have mass, you're going to need a hell of a lot of them...
It is confirmed that they do have mass. Neutrino oscillations prove this.
Neutrino oscillations are when one kind of neutrino changes into other kind of neutrino - for example, electron's neutrino changes into myon's or tau's neutrino...
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Neutrino-oscillations-are-when-one-kind-of-neutrino-changes-into-other-kind-of-neutrino-for-example, electron's-neutrino-changes-into-myon's-or-tau's-neutrino...
[O'Neill]I dare you to say that again.[/O'Neill]
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That agin,
Do i get a prize? DArk matter guns may yet become a tangible thing :D
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I see darkmatter as the unseen filler. There has to be "something" in between atoms, if there was nothing.... well I really don't know what would happen, but I doubt the atom would win the fight.
False reasoning. There does not 'have' to be anything. By what we know about the Universe at that scale, there is no reason why there should be anything between atoms except the forces keeping them seperate. Same goes for the internal structure of the atom; between the nucleus and the electron shells, there is (AFAWK) nothing except the carrier particles of the various forces that enforce that gap.
Dark matter is likely just another type of fermion with properties (spin, etc) that prohibit it from interacting with any particle other than the gravity carrier particle (assuming it exists). If gravity is not a carrier-mediated force, the definition of dark matter is simpler: it does not interact with any particle, but possesses mass.
As for Superstring being useless: not so. At present the predictions are untestable, but the model fits our current data (IIRC) making it at least as good as the standard model. Furthermore, the theory has shattered some preconceived ideas about the workings of the Universe; preconceived ideas when trying to find a Theory of Everything are not a good thing.
(http://www.nukelol.com/images/forumimages/tmyk.jpg)
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*Snip*
Swantz officially wins the thread! :lol:
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it just occured to me if gravity trancends multile dimentions it may be possible the other 3 forces have diminished or no influence over the dark mater spatial plane. there may be other forces in the universe we dont even see. like if the dark mater doesnt posess a strong atomic force, it cant fuse as atoms and thus would only exist as loose particles.
Quite. If dark matter is not affected by nuclear or electromagnetic forces, it's not going to fuse into atoms.
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indeed.
then again there could potentially be other forces at work upon dark mater that are unknown to us. the particles may form structures unique only to dark mater. indeed its possible that dark obays a completely different set of physical laws.
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Quite. If dark matter is not affected by nuclear or electromagnetic forces, it's not going to fuse into atoms.
...which is not surprising, because atoms by definition consist of nucleus and electron layers around it, and nuclei consist of protons and neutrons. And it's not surprising that protons, neutrons and electrons are not dark matter, they are normal matter that is included in standard model of particle physics.
That aside, if we drop "atoms" away from the quoted sentence and replace it with "combined particles", it starts saying something relevant.
Basic interactions include strong interaction, weak interaction, electromagnetic interaction and gravity. Of these, strong interaction (or strong nuclear force), weak interaction (or weak nuclear force) and electromagnetic force has been very accurately combined into one model that utilizes measure bosons as particles that convey these forces. In short, that's what quantum electrodynamics and quantum chromodynamics are all about.
Gravity is a mean bastard, though. It doesn't want to be quantified, but on the other hand, General Relativity does not give accurate predictions at very small ranges.
If some particles are only affected by gravitation, it's indeed very difficult to notice them. Neutrinos are almost like this; they only interact with other universe via weak interaction, which makes them very difficult to detect... And until gravity wave detectors are functional, we have no way of directly detecting dark matter... the only means of doing this would be to look for gravitational anomalies, and that has indeed been the main method of detecting dark matter thus far... in fact, it was found like that.
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If we ever discover that dark matter does coalesce at the atomic level, you can bet the definition of 'atom' will get a rewrite.
It already includes the antimatter counterpart, which doesn't consist of matter particles...</pedant>
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If we ever discover that dark matter does coalesce at the atomic level, you can bet the definition of 'atom' will get a rewrite.
It already includes the antimatter counterpart, which doesn't consist of matter particles...</pedant>
Anti-matter belongs to the class of "ordinary matter" in cosmological sense. It is affected by all the four basic interactions just like normal matter is. And anti-matter atoms behave with each others just like normal matter.
From known particles, neutrinos are the ones that are semantically closest to dark matter, but they are not truly dark either, since they interact through both weak interaction and gravity, whence dark matter is hypothesized to only interact with ordinary matter (and itself!) via gravity.
The point is that even if dark matter particles can form structures, it doesn't mean that these structures would be anything like atoms. To be that, they should have very similar properties to protons, neutrons and electrons, and if they had same properties, they would not be dark matter, they would be ordinary matter.
Just like the saying goes - if an Aunt had balls, she would be Uncle. :D
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Perihelion said, "the rules that govern the universe are actually quite simple"
Amen brother!
One of them is "Do what you want, but if you get out of line some uber race will come around to kick you in the balls..."
So I was wondering... If Dark Matter affects spacial gravity, can we use this somehow to transcend normal space into a sort of SubSpace? (Artifical wormholes anyone? I got dibbs for Wormhole Extreame!) lol :P
Out!
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Perihelion said, "the rules that govern the universe are actually quite simple"
Amen brother!
That was mostly wishful thinking, and I'll be the first to admit it. It's just... well, there are parts of Quantum Electrodynamics that have never sat well with me for much the same reasons they never set well with Einstein. I have a hard time believing in a non-deterministic universe. The fact that quantum theory comes right out and says that there are some things you flat out cannot know just leaves a bad taste in my mouth. Not to mention the implication that the universe, at its most fundamental level, is digital!
Thing is, every prediction made by QED has been proven correct thus far. Maybe human intuition is just no good at the atomic level. Sometimes I guess I let my desire for things to make sense run too far ahead. Our collective understanding of physics is getting better (more accurate, probably more "correct") everyday. But it is also getting so infernally complicated that I wonder if any one person can actually comprehend all of it without becoming the scientific equivalent of a monk.
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Why is non-determinism such a horror to you?
IMO non-deterministic world is much a relief for me, because should the world prove to be deterministic, it would also mean that there was no free will...
Non-deterministic world allows free will at fundamental level. The power of chance is a good thing to have involved IMO.
Plus, the latest experiments with single foton quantum interference really seem to prove that multiversum interpretation of quantum mechanics is the way to go. There are some phenomena that the "Copenhagen school" of quantum mechanics can't really explain, but the multiversum school can.
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hey i hate to bring on religions but wat about god?
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a non-deterministic universe does nothing for free will, it just means stuff is more random, random != willed.
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no i meant wat herra tohtori said evret (how you spell it?) interpretation is obviously against god and i say its 100% wrong. free will isnt my problem its just the idea is antichrist
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no, you don't get it, I was ignoreing you because that is beond the point of this conversation.
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Well, deities are indeed irrelevant to this subject. If we want to bring in theological controversions between predestination and free will, feel free to open a new topic. Besides, predestination is only part of some sects of monotheistic religions (primarily Calvinism and some other protestant forms of christianity), so non-deterministic universe would only be agains their god... :D
What I simply meant that if the universe is deterministic, everything just happens on a path set to happen in the big bang (or whatever it was). That would mean that free will can not be anything but an illusion.
Human free will might or might not be illusion, independent of whether the world itself is or isn't deterministic. But if the universe was deterministic, there wouldn't be even the chance that free will existed.
In a non-deterministic world, things do not happen in predestined path, so there is always a choice. In a deterministic world, there are no choices, only an illusion of making a choice. In a deterministic world, if you had sufficient information and sufficient calculation power, you could calculate what will happen to you from this day on.
And a billion year ago some sentient being could've predicted with absolute certainty that one day you'll be making those calculations.
But in a non-deterministic world, the choice is always there, randomizing events and making it truly impossible to achieve absolute accuracy with any matter whatsoever. That's what I mean with "free will". Randomized illusion of free will is more free than absolutely predictable free will.
So, in reality the human consciousness is always limited to existing possible states, but they still can't be accurately predicted.
I guess you could call human free will as "semi-free" in a non-deterministic universe. But in a deterministic universe, it's not even that, because there's only one possibility for the course of any action.
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I fail to see how the theoretical ability to calculate the future or not makes free will any less illusionary. on the microscopic scale things are still happening acording to simple rules, it's just that there might be a bit of randomness involved makeing a definate answere imposable to predict with absolute certanty.
now this all said I am what I call a mechanicist or quasi-determinst, I beleive in a universe that is run by rules, though those rules may be probabalistic in nature. I am also oddly someone who argues in favor of free will, but that is partly a function of how I have free will defined, which I don't feel like going into elaborate detail on explaining, but I think of it more of an ability of a system to learn and use past experience to make judgements about current situations, even if the choice one makes can be precisely calculated by my definition it's still free will. and I know that's not how phylosophers have it defined, but I disagree with them.
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Well, Free Will is defined by our own interpretation of Free Will. The Murderer/Victim argument is the famous example, but to break it down, we all have things we want to do, Free Will can be defined as both the urge to do it and the choice not to. However, there are some elements of Free Will that are not nearly so 'free' as we think. If you see a car coming towards you, how much choice do you think you have as to whether your body tries to get you out of the way?
If someone tries to kill you, you will use as much force as possible in return and worry about whether you killed them or not afterwards. This is why the 'Self Defence' laws are so tricky to maintain, because no-one stops and thinks 'Is this appropriate Force?' they tend to think 'Arrrrrrrgggh!' at around that stage.
And, not going too philosophical, but 'Arrrrrrrgh!' has had far more to do with human development than any other thought.
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Enough about Deities! ! !
Dark matter has to exist, because matter doesn't have an opposite. Let's see, there is: White and Black, Good and Evil, Spartan_0214 and Dark Hunter, Macintosh and PC, you name it, it has an opposite. Dark Matter must exist. . . .
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Not neccesarily, after all, you get things like 'Cold', 'Silence' etc, which are an absence of something, heat and sound in these cases, there is no such thing as 'Cold Energy' (Well, yes, Quantum Physicists would disagree, but that's a different sort of Cold Energy) all there are is Materials without any heat energy.
You could say that the opposite of Matter is Vacuum.
Theres no reason why Dark Matter cannot exist, it is simply mater that has congealed too far away from a light-source to be illuminated, but until our ability to detect it improves greatly, I will remain sceptical as to just how much of it is out there.
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stop defining the universe in a human centric manor. the universe operates independant of human belief and pholisophy.
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:wtf: centric or eccentric? :wtf:
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@ Flipside:
While it is possible to explain some of the missing mass of the universe away as normal baryonic matter that simply is not sufficiently illuminated to be seen (i.e., brown drawfs and other dwarf stars, cold interstellar gas and dust, neutrinos, etc.), most of that missing mass simply cannot be explained without either seriously rewriting general relativity or the presense of a very large quantity of matter which does not interact with visible matter in any way other than gravity.
http://en.wikipedia.org/wiki/Dark_matter (http://en.wikipedia.org/wiki/Dark_matter)
It's not the most rigourous article out there, but it does cite some good references and gives a good introduction to most of the theories out there.
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Yup, though personally, I'm not against looking at the laws of General Relativity. Personally, I find it more believable to think there is only one 'kind' of matter in the Universe and we just don't understand every aspect of it yet rather than start inventing new kinds.
I may be wrong, I'm no scientist, but as a scientist said 'When physicists start talking about matter who's only proof of existence is the fact it is almost impossible to detect, you can almost smell the paradigm shift coming one way or another.'
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now this all said I am what I call a mechanicist or quasi-determinst, I beleive in a universe that is run by rules, though those rules may be probabalistic in nature. I am also oddly someone who argues in favor of free will, but that is partly a function of how I have free will defined, which I don't feel like going into elaborate detail on explaining, but I think of it more of an ability of a system to learn and use past experience to make judgements about current situations, even if the choice one makes can be precisely calculated by my definition it's still free will. and I know that's not how phylosophers have it defined, but I disagree with them.
There are about as many definitions of free will as there are philosophers. You could define free will as "a purple banana" and there would be a philosopher (probably some twentieth-century scholar of epistemology) who would be right there with you.
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does said purple banana vibrate? :D
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You'd need to change the batteries.....
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anyone here seen Batteries Not Included?
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I cried my heart out when the little guy came back to life :(
(i was about 8 so sue me)
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spartan liked said movie, but it wasn't his favorite. how on God's Green Earth did we get to batteries?
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It beats Caccon, thats ust a load of plop, BNI flying saucer lifeforms probably got me hooked on space combat games actually..........
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Top Gun (wierd huh) got spartan wondering if there were any videogames on PC that would be flight sims (spartan was much younger, and much inexperienced)
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The only good topgun game can be found in most holiay camps, Or beachfront arcades both in the uk and spain, Its the sit in one with 16bit technology WOOT!
(But nothing beats operation wolf)