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Quark Stars
BigGar' writes "Astronomers seem to have discovered a new type of star. It would lie between a neutron star and and a black hole in the hierarchy of stars and consist of quark matter. Further observations with the Chandra X-ray telescope will be needed to confirm the results."
I had read once that black holes could be regarded as super-large elementary particles (described by very few parameters: spin, charge, mass). Would "quarks stars" be something like that, or more like a huge Bose-Einstein condensate?
Jes curious....
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This stuff looks dense enough to be a black hole (black hole in the sense of "light can't get out", not necessarily "singularity"). So, what kind of densities do you need to get a blackhole, or does the total mass also enters the equation?
It is possible to tie a particular supernova remnant (and this is the only way ultra-dense stellar remnants are created) to an event witnessed in the past; indeed this is often done. Supernovae occur so infrequently in our galaxy (one every 100 to 500 years or so) that it is often possible to do so. For instance, it is very well known that the Crab Nebula is the remnant of the supernova witnessed by Chinese astronomers in 1054 AD.
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I didn't want to leave this space blank.
Quark stars are a new and interesting idea, but quark matter in general is not a new idea. "Quark matter", more usually "quark plasma" or "quark-gluon plasma", is believed to be the dominant form of matter in the universe just following the big bang. There is also early evidence that it's been witnessed in some of the largest particle accelerators.
In normal matter quarks group together in sets of 3 to form protons and nuetrons. Rare particles, like pions, can be formed from pairs of quarks, but quarks never appear in isolation, for them it's always in groups of 2 or 3. In quark plasmas though there aren't any distinct groups of twos and threes. All the quarks are smushed into a single substance with arbitrarily large numbers of quarks.
One analogy is if atoms are built out of "solid" quarks (in the from of protons and nuetrons), then the quark plasma is like melting them so they all run together. Prior to this announcement the only time that quark plasmas were expected to appear was in the presence of extraordinarily high energies and temperatures.
We could predict that nuetrons stars should exist because the "nuetron degeneracy pressure" which makes them possible was well understood theoretically. The theory that governs quark interaction is known as quantum chromodynamics and is far more complicated. I'm not sure whether anyone knows how to apply it to massive collapsing stars, and it doesn't surprise me if no one ever tried. It will be interesting to see if the existing theory can be made to justify quark stars. If not, well that's when things really start to get exciting.
And are you suggesting that the work being done in Astronomy/Cosmology in the U.S. is costing BILLIONS of dollars? C'mon, man, get a grip! And I firmly reject the idea that only "humans in space" can effectively explore and exploit worlds outside ours.
If we have learned anything from the last few decades, I think it's that technology is an extension of our senses into the universe outside of our bodies... so why do we have drag our frail monkey-bodies to Mars if we can get the raw data cheaper and more safely with instrumentation? So we can play golf there too?
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You say, "Newton, Einstein, etc.", but think about the gap between those two theoretical branches. It's huge! Newton was completely unaware of the principles behind Einstein's work and based his model on nothing but observed phenomena, right? Of course, that doesn't mean that Newton is bunk, just that it's accurate for observed phenomena within a specific range. Einstein's range is much larger, including things that Newton couldn't possibly have measured to note discrepancies. One must assume that future discoveries will continue to provide larger and larger frames of reference, not supplant what we have. However, the change will be in our understanding of the boundary conditions, not of easily observed things. Heck, how are we doing research now? Particle accelerators! That ain't your everyday environment...
Here is a more in depth report from NPR's Wednesday broadcast of All Things Considered (in Real Audio format).
If you lived 150 years ago, what would your idea of "communication technology" be like?
Without Planck trying to understand blackbodies, Quantum Mechanics might never have had the kick it needed, to get Bohr's ponderings into the structure of atoms. In 1900, most problems seemed nearly solved, except for two little "clouds on physics' sky" as noted by Kelvin. It turned out that these two clouds would lead to QM and relativity. And they had quite a lot to do with observations done in astronomy.
Without these ideas, there would be no semiconductors, there would be no computers. You wouldn't be posting to /. if it hadn't been for those looking into the most fundamental questions of their time.
Quarks, quark-gluon plasma are among the most fundamental questions of our time.
What would a manned mission to Mars give us? Well, some kewl tech, quite a lot of resources into research, and probably also a positive long-term effect following from the increased attention given to science.
But it is not likely to be of fundamental importance to our world-view. It is not likely to do anything to give us understanding that is going to be used in that kind of technology you can't even imagine today.
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Much could have -- and was! -- said about the original accelerators. Why spend all this money whipping protons around a ring? Why not do something "practical"? Say, like medical research. Cure diseases instead of peering at tiny particles.
Interestingly enough, much of what we know about microbiology can be traced back to synchrotron radiation labs. At Stanford, the "waste" photons generated by the synchrotron ring turned out to be useful in X-ray crystolography (I assume the same at other facilities). Now SSRL is so important it can compete with the physics experiments in control of beamtime on the accelerator. All from some "impractical" studies.
The nature of research -- frsutrating as you might find it -- is that you never know, ahead of time, what will be a dead end and what will be "practical". The history of the past few centuries indicates that basic research nearly always ends up enhancing "normal" life.
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As for the spectral fits, their main objection to the two component fit (which is required to fit the optical data, BTW) is the lack of pulsations. But there is a ~15% chance of having no pulsations even _with_ a hot spot(s) and a two component blackbody.
If there is no cool BB component, then they are correct that a very small radius is required -- and that could imply a quark star. I don't think this is the most likely answer, though (especially since it doesn't explain the optical data).
As for the distance, I think that the 140pc distance is probably correct. There is a bunch of evidence pointing that way, and at least three people have independently analyzed the HST data and found the larger distance vs. 1 for the smaller....
So in summary, I personally think that there is a two component BB, the hot supplying the x-rays, the cool supplying the optical, and an unfortunate geometry causes the lack of pulsations. This means that RX J1856 is just a normal everyday neutron star...