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from the can-a-black-hole-radiate-back-into-a-neutron-star? dept.
Physicist Proposes Alternative to Black Holes
A physicist has incorporated a quantum mechanical idea with general relativity to arrive at a new alternative to black hole singularities. What do you get when you cross two hypothetical alternatives to black holes? A self-consistent semiclassical relativistic star, according to Raúl Carballo-Rubio (International School for Advanced Studies, Trieste, Italy) whose recently published results in the February 6th Physical Review Letters [DOI: 10.1103/PhysRevLett.120.061102] [DX] describe a new mathematical model for the fate of massive stars.
When a massive star comes to the end of its life, it goes supernova, leaving behind a dense core that — according to conventional thought — continues to collapse to form either a neutron star or black hole. To which fate a particular star is destined comes down to its mass. Neutron stars find a balance between the repulsive force of quantum mechanical degeneracy pressure and the attractive force of gravity, while more massive cores collapse into black holes, unable to fight the overwhelming pull of their own gravity.
Now, Carballo-Rubio adds an extra force into the mix: quantum fluctuations. Quantum mechanics has shown that virtual particles spontaneously pop into and out of existence — the effects can be measured best in a vacuum, but these fluctuations can happen anywhere in spacetime. These particles can be thought of as fluctuations of positive and negative energy that under normal conditions would cancel out. But the extreme gravity of compact objects breaks this balance, effectively generating negative energy. This negative energy creates a repulsive gravitational force. "The existence of quantum [fluctuations] due to gravitational fields has been known since the late 1970s," explains Carballo-Rubio. But physicists didn't know how to take this effect into account in collapsing stars.
Carballo-Rubio derived equations that combine general relativity and quantum mechanics in a way that accounts for quantum fluctuations. Moreover, he found solutions that balance attractive and negative gravity for stellar masses that would otherwise have produced black holes. Dubbing them "semiclassical relativistic stars," these compact objects do not fully collapse under their own weight to form an event horizon, and are therefore not black holes.
(Score: 3, Insightful) by Snotnose on Sunday March 25 2018, @12:13AM (7 children)
when you need him? Just reading the summary makes my brain hurt, and I'm smarter and better informed than the average bear. Um, that would be a Yogi Bear reference, not a gay hookup reference.
Sad I have to quantify bear, but that's the world we live in.
My ducks are not in a row. I don't know where some of them are, and I'm pretty sure one of them is a turkey.
(Score: 3, Interesting) by takyon on Sunday March 25 2018, @12:28AM (2 children)
At first I thought this was someone coming out to shit on the recently deceased Stephen Hawking and the concept of black holes entirely (which should be "directly imaged" any month now [earthsky.org]). But it looks like edge cases between neutron stars and black holes.
"Vacuum fluctuations are always created as particle–antiparticle pairs" or virtual particles. They pop into existence, and cancel each other back out. But if they form near the event horizon of a black hole, one particle can escape while the other drops into the black hole, and the black hole loses a tiny bit of mass. That's Hawking radiation.
Apparently, instead of collapsing into a singularity like normal, you could have some virtual particle weirdness contribute an outward force that just barely stops the stellar object from becoming a true black hole.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 1) by west on Sunday March 25 2018, @12:09PM (1 child)
wonder what it would be made out of, since the neutron degeneracy pressure is overwhelmed but there is no event horizon. quarks?
i wonder if they did the math at how this object would radiate. i would guess more than a neutron star. it would be smaller and maybe rotate faster. should be able to point out some possible candidates in the sky if we knew some of these things by maths
(Score: 2) by fraxinus-tree on Sunday March 25 2018, @02:27PM
Radiate more it will not. Even the neutron stars are crazily red-shifted and have only a few tens of square kilometers surface to radiate from. That's why we see mostly their accretion artifacts (the jets and the x-ray emission from the accretion disk). And the black holes are no better and we see generally the same. The objects in question lies somewhere between those two and we still have a hard time differentiating them. The main difference is the magnetic field and how it modulates the disk and the jets.
We previously had at least two more "compact star" models between the more or less proven neutron star and the black hole - the quark star and the preon star. This Italian guy just adds a theory for one more exotic ball of mass on the road to the inevitable. Good luck seeing the differences.
(Score: 2) by edIII on Sunday March 25 2018, @12:51AM (3 children)
I couldn't bear not pointing that out :)
Technically, lunchtime is at any moment. It's just a wave function.
(Score: 2, Funny) by khallow on Sunday March 25 2018, @05:36AM (2 children)
I hope I don't run across one of these guys this summer!
(Score: 2) by edIII on Sunday March 25 2018, @06:52AM
I thought that would be self evident. A Quantum Bear explores all states simultaneously. It's in infinisexual.
Technically, lunchtime is at any moment. It's just a wave function.
(Score: 2) by wonkey_monkey on Sunday March 25 2018, @06:18PM
You don't know where it poops until you've trodden in it.
systemd is Roko's Basilisk