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posted by martyb on Saturday March 24 2018, @08:38PM   Printer-friendly
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.


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  • (Score: 2) by edIII on Sunday March 25 2018, @12:51AM (3 children)

    by edIII (791) on Sunday March 25 2018, @12:51AM (#657725)

    and I'm smarter and better informed than the average bear.

    Sad I have to quantify bear, but that's the world we live in.

    I couldn't bear not pointing that out :)

    --
    Technically, lunchtime is at any moment. It's just a wave function.
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  • (Score: 2, Funny) by khallow on Sunday March 25 2018, @05:36AM (2 children)

    by khallow (3766) Subscriber Badge on Sunday March 25 2018, @05:36AM (#657802) Journal
    So how does a quantum bear work? No one can tell if you're mauled or not, until they observe you? (Or rather mauled states are entangled with non-mauled states)

    I hope I don't run across one of these guys this summer!
    • (Score: 2) by edIII on Sunday March 25 2018, @06:52AM

      by edIII (791) on Sunday March 25 2018, @06:52AM (#657816)

      So how does a quantum bear work?

      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

      by wonkey_monkey (279) on Sunday March 25 2018, @06:18PM (#658005) Homepage

      You don't know where it poops until you've trodden in it.

      --
      systemd is Roko's Basilisk