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Exotic "Electroweak" Star Predicted
astroengine writes "A new type (or phase) of star has been characterized by Case Western Reserve University scientists in a paper submitted to Physical Review Letters. The 'electroweak' star is a stellar corpse too massive to be a quark star, yet too light to collapse into a black hole. It crushes and burns the quarks inside, generating an outward radiation pressure that acts against gravity. Interestingly, the interior is predicted to be a 'Big Bang factory,' forcing the electromagnetic and weak forces to collapse as one (hence 'electroweak') — a condition that hasn't been seen elsewhere in our universe since moments after the Big Bang." The article notes that the first calculations on electroweak stars pegged them as an intermediate stage on the way to a black-hole collapse, lasting at most a second. The new calculations suggest that electroweak stars could persist for millions of years.
Here is the scientific paper.
As a physicist, I feel that this is a little far out. It assumes violation of the conservation laws for baryon number and lepton number. They claim that this nonconservation is actually predicted by a loophole in the standard model, which may be true, but it's never actually been observed -- if anyone observed such a violation experimentally, they'd definitely get the Nobel prize.
It's also built on a particular model of quark-quark interactions. (The strong nuclear force is not an interaction for which we have an exact formula. All we have is various models of it.) All the predictions are therefore going to be dependent on this model, as well as on the other approximations they have to make. People have predicted other weird objects, such as quark stars, using similar models, and the predictions have turned out to be very hard to pin down in any model-independent way. Some theorists use different methods, and come out with completely different predictions. Nor has any really compelling experimental evidence turned up for quark stars, although there are a couple of candidate objects that seem too dense to be ordinary neutron stars. If there's no solid evidence for quark stars, it seems like quite a stretch to go beyond that and predict things about even more exotic objects. The landscape is littered with predictions of exotic objects along these lines: quark stars, strange stars, black stars, gravastars, fuzzballs, boson stars, q-balls, ...
They recently revised their estimate of the lifetime of these objects, making it ~10^7 years rather than a fraction of a second (only 14 orders of magnitude different). Even though 10^7 years is fairly long, it's really not very long on cosmic timescales, so we would expect these to be fairly rare and hard to find, even if they did exist.
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Someone said: "This isn't physics. It's math and programming, with someone interpreting it as a physical possibility."
Someone replied: "That's what theoretical physics is. It's the experimentalists and observationalists who confirm or refute the theorists' predictions."
The replier here is absolutely correct. Many kinds of stellar objects were first predicted by Theoretical Physicists before being observed. Why? Well, predictions like this can tell an observerational astronomer what to look for. In fact, black holes were predicted to exist in the 18th Century(!) but were largely ignored until the Einstein's theory of General Relativity proposed a radically different idea about what gravity is which also predicted a method by which light (then thought to be a massless wave and therefore totally unaffeted by gravity) could be "trapped" or bent around a black hole. Einstein predicted a gravitational lensing effect around masses of sufficient size, later confirmed during an eclipse of our own sun. Still later, Stephen Hawking predicted the existence of Hawking Radiation that should be detectable as well coming from near the event horizon of black holes. They were both right, but observational astronomers would not have known what the f#ck they were looking at once a black hole was first observed without the theortical groundwork that was laid first.
If the semi-diameter of a sphere of the same density as the Sun were to exceed that of the Sun in the proportion of 500 to 1, a body falling from an infinite height towards it would have acquired at its surface greater velocity than that of light, and consequently supposing light to be attracted by the same force in proportion to its vis inertiae, with other bodies, all light emitted from such a body would be made to return towards it by its own proper gravity. —John Michell[2]
In 1796, mathematician Pierre-Simon Laplace promoted the same idea in the first and second editions of his book Exposition du système du Monde (it was removed from later editions).[3][4] Such "dark stars" were largely ignored in the nineteenth century, since light was then thought to be a massless wave and therefore not influenced by gravity. Unlike the modern black hole concept, the object behind the horizon of a dark star is assumed to be stable against collapse.