Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Hawking radiation and information

  1. Mar 6, 2014 #1
    say you measured every particle which has entered a black hole
    say you measured every hawking radiation particle which exits the black hole

    my understanding is that if like... a proton enters the black hole, then an anti-proton needs to be emitted via hawking radiation. so if you measure every particle the black hole ever emits, you should be able to reconcile both the number of particles which have entered the black hole, and the type of particle which enters the black hole (ie proton, neutron, electron)

    has the information been conserved after the black hole evaporates, or is some information still missing? is my understanding even accurate? thanks
  2. jcsd
  3. Mar 6, 2014 #2


    User Avatar
    Science Advisor

    Hawking radiation does not come from inside the black hole. It comes from the nearby surroundings.

    Hawking radiation is a thermal mixture of all types of particles. What is emitted bears no relation to what type of matter has fallen into the hole.
  4. Mar 16, 2014 #3
    if you measured a given hawking radiation particle, what would it look like?
  5. Mar 16, 2014 #4


    User Avatar

    Staff: Mentor

    It's a particle, so it has various properties that can be measured: energy, mass, momentum, ...

    You'd measure any of these for a particle emitted by the Hawking process the same way you'd measure that property for a particle emitted by any other process. And as Bill_K says above, that measurement tells us nothing about what went into the black hole; Hawking radiation doesn't come from inside the hole.
  6. Mar 16, 2014 #5
    well, i understand (i think) that each pair of virtual particles is 0 energy combined. the particle which escapes the black hole becomes real (and therefore has positive energy?) while the other one falls into the black hole and contributes negative energy any particle transfers negative energy

    is this at all correct?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook