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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....
I'm a bloodsucking fiend! Look at my outfit!
"Neutron stars are the vestiges of immense supernova explosions, collapsed stars with extremely compact cores, denser than all known objects except black holes. A teaspoonful of a neutron star would weigh one billion tons, as much as all the cars and trucks on Earth."
That would be one impressive teaspoon.
Tall, Blonde and Weaponized
tcd004
Does anyone know if all up quarks are the same as all other up quarks and if all down quarks are the same as all other down quarks? There might be a billion different slight variations of the two kinds. We don't have the equipment to define a quark past a certain level.
Job? I don't have time to get a job! Who will sit around and bitch about being broke and unemployed then?
I guess Armin Shimmerman was pretty cool, but I don't think he's really a star... Or was that a different kind of Quark, that doesn't try selling self-sealing stembolts...
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.
Or as Mr D. Vader would put it:
If you only new the power of the quark side...
Beware: In C++, your friends can see your privates!
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?
I've got a bad attitude and karma to burn. Go ahead. Mod me down.
The protons and electrons go through a reverse beta decay to form neutrons and neutrinos. Not all protons and electrons are consumed in this fashion which lets the following ideas progress, the outter shell of a neutron star is covered with a bunch of high energy electrons and protons exisiting in the crust of the neutron star can be in a super fluidic state making the neutron star a gigantic super conductor. Electrons being annhihilated on the surface release X-Rays which get funneled by the intend magnetic field of the super conducting protons into beams which create the effect we dub a pulsar.
I'm a loner Dottie, a Rebel.
Something that one gets used to in science is that you don't know anything in the absolute sense, but you probably do "know" things to the degree that you're willing to base your life's work off of them. On the other hand, if you spend too much time around philosophers, you might end up wondering if the world really exists, or if your senses are accurate, etc.
Doubt goes hand in hand with wisdom. Once one accepts that there is room to question absolutely everything, then you just have to accept the attitude of estimating what is the most likely truth and working from there. In my (admittedly biased) estimation the laws of physics, as currently understood, are almost certainly a good approximation of truth, though certainly not the last word.
In science, careers are made by showing that the established beliefs are wrong. There are lots of people itching to overturn current theories. Sometimes there is resistance if the evidence is weak or the argument complicated, but in the long run scientists are often more likely to admit their mistaken beliefs than the public in general.
If there really is a right answer to the universe then an independant thinker should arrive at similar conclusions to the ones we already have. Unfortunately no man ever born could even learn all the science we have now, so it's nigh impossible to believe that any single person could have the capacity to independantly arrive at more than a very small part of what has already become established doctrine. On the other hand, Ramanujan did quite well, and without being shunned or killed.
If some day we do contact an intelligent alien race, that would be other best chance to study an independant notion of science. However, I doubt that they'll offer too many surprises among the areas of science that have been studied in detail.
It wasn't mentioned in the Chandra release or the CNN spot, but RX J1856.5-3754 is apparently the closest known neutron star. The Chandra site states it's distance at ~400 lyr and the APOD site cites 180 lyr, practically in our back yard!(in cosmological distances anyway)
- "Hear that?! The percolations are imminent! Cease your ingress!"
Well, there is no revealed truth in science, so we don't ever know absolutely that something is real. It has happened before that a theory turns out to be based on a house of cards. Most of that time, in retrospect, it can be seen that the theory got way out in front of experiment and so was improperly constrained. That is, the less we've studied an area, the more likely the theoriest are wrong. As facts come in, theories get revised or strengthened.
On the other hand, remember that in physics, most "revolutions" change our understanding of how things work but do not invalidate existing theories in their realm of applicability. For example, relativity didn't kill Newtonian theory. Indeed, that's still where we start today in physics education. Why didn't it? Because at human-scale speeds, with human-scale masses, objects obey Newton's Law pretty well... that's the region in which the theory was derived and it fits the experiments there. At the very fast, it breaks down, and then relativity is needed.
Now, we insist the Universe is "really" relativistic at all speeds, so in that sense the new theory wiped out the old. But we also insist that for slow objects relativity must reduce to Newton's Law (and it does). So the earlier theory reamins a useful, if admittedly inadequate, tool.
The Mongrel Dogs Who Teach
Why? One way of looking at the vacuum is that it is filled with virtual particles. A group of virtual particles can "borrow" energy to spring into existence, and then annihilate after a short period of time, returning the borrowed energy to the vacuum. The time scale they are allowed to exist is governed by Heisenberg's uncertainty relation. (E*t>=h-bar.) For massive particles like electrons, it's a short period of time.
If, during their short existence, the electric field can do more work on the particles than their borrowed energy, the "debt" to the vacuum can be "repaid", and the particles can become real.
-- ;-)
Kuro5hin.org: where the good times never end.
Also, you've fallen prey to a terrible, terrible fallacy that afflicts even good astronomer: the dreaded Selection Effect. How do you think they "happened" to come across this odd object? Almost certainly, because they were already studying the nebula and remnant. In other words, it's not out of the many billions of stars that they chose. It was out of the much much smaller pool of SNRs.
The Mongrel Dogs Who Teach
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.
Employee of Inrupt, Project Release Manager and Community Manager for Solid
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.
The Mongrel Dogs Who Teach
I did a PhD on pulars, which everyone thinks are neutron stars. At one point I found a paper which suggested that instead they might be "strange matter" stars - and it's always intrigued me how difficult it is to distinguish between the two.
The cool thing about finding strange matter stars is that it suggests there's a lower-energy state of matter than our normal up/down quark pairings. No one's really sure because QCD is so hard to get numbers out of.
Every time they build a new accelerator someone harps on this, worrying about whether we'll ram particles together hard enough to create a meta-stable bubble of strange matter. If there is a net saving in energy due to expanding that bubble (drop in energy due to increasing volume of lower-energy-state matter, increase in energy due to increased surface tension on the surface), the bubble will tend to expand and gobble up everything in its path - like the Earth, for example.
That's the common worry, though it's easily allayed by noting that particles with much higher energy than anything we could create in an accelerator are hitting our atmosphere all the time, and none of them have turned our planet into a jiggling mass of strange matter.
Anyway, interesting idea.
All opinions expressed herein are not my own; I haven't had free will since last year when aliens ate my brain.
I am one of the authors of a competing paper on RX J1856 that was published yesterday, as well as a co-discoverer of the pulsar in 3C58. In my opinion these results, while definitely a possibility are certainly very preliminary. And in fact, there are other possibilities that make quite a bit more sense.
In the case of RX J1856, there is a ~15% chance that the lack of pulsations (one of the biggest reasons for suspecting a quark star) is simply the result of an unfortunate emitting geometry or viewing alignment. Given that there are ~7 objects known that are similar to RX J1856, having at least one of them in this 15% seems quite likely to me -- and avoids having to invoke a new form of "star stuff".
As for 3C58, the neutron star cooling problem can be mitigated (but not completely removed) by assuming a larger age for the supernova remnant (and therefore the neutron star) -- which expansion measurements and pulsar timing measurements also suggest.
In other words, there are simpler explanations for the facts. Although those explanations certainly wouldn't get as much press...
In other news, degenercy isn't a LAW. If it was, then black holes couldn't exist. It's more of an aproximation of other forces, kind of like how we define Normal forces.
Degeneracy is a fundamental feature of the quantum theory of fermions. It isn't an "approximation of other forces". The concept of a force is only applicable at a higher level. Quantum theory is concerned with interactions.
Black holes exist because as a neutron star gets bigger, additional neutrons require more and more energy. All the low energy states are occupied. Soon the neutrons have more energy than you see in an accelerator, and they can react to form other particles. Particles that aren't neutrons won't compete with neutrons for the higher energy states.