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Theory Posits Early Stars Powered By Dark Matter
ethericalzen writes "A BBC article highlights a theory that the first stars may have been powered by dark matter. A group of US scientists published a paper in Physical Review Letters speculating that, unlike the stars of today, which are powered by nuclear fusion, early stars might have been powered by the abundant dark matter crowding the universe after the Big Bang. The theory suggests that these stars would have collided and destroyed one another before nuclear fusion had a chance take hold." The BBC perhaps overstates the certainty with which the dark-matter theory is held, and doesn't mention that the postulated properties of such particles are completely speculative.
Maybe that's where all that Dark Energy came from.
There is no "I disagree" mod for a reason. Flamebait, Troll, and Overrated are not substitutes.
How do you overstate the certainty of dark matter? Last I read, the only serious alternatives were that there's more interstellar dust than we thought (improbable considering the observations of the bending of light), modifications to the theory of gravity (few supporters, unlikely, especially with said observations), and string theory.
How can something so dark create so much light...
First off, dark matter isn't dark but transparent. Then, how could say methane and oxygen which are transparent create light when burning together? Oh I know! Maybe that's because it's not the matter that releases light/energy but its transformation.
You just got troll'd!
everything is explained by dark matter. Universe heavier then we think it should be? dark matter. can't figure out the big bang? dark matter. I bet soon enought someone will figure out a way to tie dark matter to the cables in the middle east that got cut the other day.
-- All this knowledge is giving me a raging brainer.
Maybe a better word/phrase for this would be "interesting idea being bandied about".
Its use of "theory" like this that give the mouth breathers down in Florida and excuse.
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after all:
1. Nibblonian civilization predates the Big Bang by 17 years.
2. Nibblonians poop dark matter.
Ergo, the first stars were made of Nibblonian poop.
Here's the LANL preprint: http://arxiv.org/abs/0802.1724v2
Don't we have a pretty concrete definition of what a "star" is? If these early objects were actually composited of dark matter, wouldn't they be something else?
For example, a tennis ball and a "tennis-ball-shaped" object made of iron are two very different objects. I know which one I would like to have hit me in the head.
... and where did the dark matter come from? Well it was created from normal matter by running time backwards.
Engineering is the art of compromise.
If this was a simulation, would you simulate very atom? Or would you bulk compute matter that was less important, until it became important then simulate every atom?
Could dark matter, or matter we have trouble seeing, be the equivalent of hiding polygons which don't need to be rendered in a 3D scene?
Geez, I hope not. Quick, prove me wrong.
M0571y H@rml355.
Actually.. methane and oxygen are colourless... My physics teacher practically beat us to death with that one.
Dark matter stars make BLACK LIGHT?
That's not accurate, there is much evidence supporting the idea of massive particles which do not interact via the electromagnetic, strong, or weak forces. There is, for instance, the observation of lensing in the Bullet Cluster last year which put to rest many of the modified gravity theories. There is also the recent observation reported earlier on /. of a galaxy composed of stars whose motion can be described without dark matter. The latter observation is particularly damning, if the effect were due to a misunderstanding on our part of the gravitational force or some quantum mechanical property of normal matter then it should be seen everywhere.
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Dark Matter was just one hypothesis among many for why galaxy rotation wasn't as expected until we started getting the very precise measurements of the cosmic microwave background radiation a couple of years ago. That made it clear that the matter mass of the early universe was about 80% non-baryonic, reacting to gravity but not light pressure. The percentage and distribution was predicted well by a dark matter theory, and it has explained some later observations as well.
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Yeah, now if only they had observed dark matter, that would be a real breakthrough.
Actually.. methane and oxygen are colourless... My physics teacher practically beat us to death with that one.
Didn't see it coming?
The dark matter worn on the faces of early minstrel stars was certainly key to their star power.
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Not that it really matters, because our perceptions will also be different in those places :P I suppose if the frames are localised then that's one way of being able to measure the differences though, rather than just theorising.. possibly by sending an atomic clock in, retrieve it, and see how much difference in time had elapsed? Though if the journey is long then the speed at which the clock is moving would also change how fast it 'ticks', or warp time around it, whatever you want to say. Or is there a more efficient way to do it just via observation, taking into account for example that if the speed of light in there is veeeeery slow, how are you going to be able to tell? Actually I guess you could see patterns of stars around the edges that have since moved/changed intensity or something, but can still be seen by looking through the frame? Or are the chances of an area with an incredibly slow speed of light not very high?
Actually I just got a little excited there thinking about if the speed of light was faster, you'd be able to see things happen before you normally would, if there was a frame that accelerated the speed of light. I guess the practical upsides to learning all of this could be something like 'subspace' in Star Trek, allowing us to have faster than earth-light travel and communication?
which is totally what she said
How about: "These particular results of the use of Math do not really make sense, and we cannot really verify/falsify them. It's fun, but right now I have to do some shopping, so I'll go build a bridge or do something for which I can get paid, and with the money I get I'll buy that second-hand Cray you saw yesterday and we'll be back in the business of discovering particles that are so small that, if Heisenberg was right, we can't know much about them but a product of their speed and of their mass, or back in the business of counting the number of angels that can dance on the head of a pin, if you fancy that more."
The singularity is about to explode!
Considering that the need for Dark Energy to explain the expansion of the universe is in question, I don't know. We know very little about Dark Matter and Dark Energy. Now we hear that our own galaxy might be twice as thick as we previously thought. Dark Energy and Dark Matter are added to observed data to come up with models to explain observations. I'm thinking if 75% of the energy in the model is no longer required to explain observations and the 4% of free hydrogen and helium might be doubled that maybe we should take a look at the 25% that is Dark Matter as well.
for the fact that MOND gives good results.
There is nothing wrong with Dark Matter(DM) as a concept. It is certainly possible that DM exists. The only problem with DM (at least at the Galactic scale) is that MOND gives very good results. Its like the Max Planck's corpuscular theory of Black Body Radiation. Planck assumed that radiation could only have some allowed energy levels. This assumption was able to fit the Black Body Radiation curve very well. This is how Quantum theory was born.
Now MOND is similar in nature. It is based on an assumption that at a certain acceleration level gravitational pull no longer drops at r^2 with distance, but drops at r with distance. It is actually defined as a geometric mean of the acceleration due to Newtonian gravity and the special acceleration level. This simple modification works very well at the Galactic level.
DM at galactic scale would be perfectly fine if we did not have MOND work so well.
The other fact is that MOND does not work well beyond galactic scale. I believe that both approaches could be true. MOND and DM can both be true. I suspect that DM could be spread out nearly uniformly. The density might not be sufficient to produce much gravitational effect at galactic scales, but at larger scales, it may produce a large observable effect.
MOND can be explained very easily by GR, if the universe is curved. The problem is that flatness is considered a settled question.
The proposed idea that early stars were made of dark matter, etc. is pure speculation. Speculation is NOT a theory. Let's review: scientifically speaking "a theory is a systematic and formalized expression of all previous observations, and is predictive, logical, and testable" [wikipedia]. A theory also is built on a substantial mathematical/physical/chemical foundation on which it rests. Unfortunately there is an air-headed defintion that 'theory' is a speculative conjecture, opinion, or untestable notion; but only numbskulls think along those lines. Also, dark matter and dark energy are in themselves nothing more than speculative conjectures ... there is currently NO theory of dark matter nor of dark energy. In time, a workable theory involving them will no doubt be built.
How weakly do Weakly Interacting Massive Particles interact? Now we have them colliding and annihilating themselves? Often enough to create enough pressure to offset the gravity trying to pull the "star" together? Just how wimpy are your WIMPs?
And I also am not convinced these hypothetical objects should be called "stars." Quark stars and neutron stars were at least formerly fusion-powered stars before losing their morals and becoming degenerate matter.
You mean it wasn't pennywhistles and moonpies?
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...that the Dark Side created the universe.
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matter isn't uniform everywhere. why should dark matter be? so there's a rogue galaxy that's somehow missing dark matter. what about the dark matter inside you?
karma: neutral
Is this good enough?
DNA just wants to be free...
Your physics teacher misled you in this case. They certainly have absorption spectra: they're merely colorless in the visible spectrum.
And heat them up to stellar temperatures, and see what colors theyy glow!