PDA

View Full Version : Hawking Radiation...



Trocisp
2008-Oct-10, 09:50 PM
Let me preface with the statement that I understand almost nothing about hawking radiation, and have no formal training in the subject whatsoever. So my question may very will be asinine.

I was watching a special about, I think Hawking, and it explained hawking radiation as the Negative Mass particle that passes by the event horizon, lessening the mass of the singularity.

I'm with that - and I understand.

What I don't understand is why an equal number of Negative and Positive mass particles don't get sucked in. According to the laws of large numbers, shouldn't they average to be the same?


And it occurs to me as I'm typing this out - is there something inherently different about the positive and negative mass particles? Do the Negative Mass Particles move much slower, meaning that their escape horizon is much larger than the positive mass particles?


Or, perhaps, is my question completely nonsensical, because that's happened before too...

alainprice
2008-Oct-10, 10:31 PM
A negative mass particle could be used for a perpetual motion machine, so I'm gonna stop you right now and ask that we call all masses positive. We might very well consider their energy contribution to be negative, depending on the reference level.

1) particles appear near and outside the event horizon.
2) one particle falls in, one escapes
3) the energy to create the particles was borrowed from the BH's gravity, therefore the only way for the BH to not lose mass is to always absorb both particles.
4) There is no negative mass involved. All mass considered is normal and positive.

5) wasn't this already posted elsewhere?

grant hutchison
2008-Oct-10, 10:38 PM
I think you watched the same special that made Fazor start this thread (http://www.bautforum.com/questions-answers/79715-matter-anti-matter-bh-question.html).

Grant Hutchison

Trocisp
2008-Oct-10, 11:27 PM
I think you watched the same special that made Fazor start this thread (http://www.bautforum.com/questions-answers/79715-matter-anti-matter-bh-question.html).

Grant HutchisonYes, yes I think I did.

I even tried looking for very close subjects.... :doh: I just didn't have any of those specific words in mind, so it didn't come up.

Sorry for the duplicate thread, guys.

Ken G
2008-Oct-11, 05:04 AM
What I don't understand is why an equal number of Negative and Positive mass particles don't get sucked in. According to the laws of large numbers, shouldn't they average to be the same?
This came up in the other thread, but bears repeating, because it sounds reasonable. That doesn't matter much, as none of us know how to do the requisite calculation, so this is all highly speculative. But there is a general principle about virtual particles (which can have negative mass) which is that they are usually only allowed to have an impact temporarily, as negative mass particles are disallowed for longer times, and positive mass particles would need to find an energy source to, like Pinocchio, become a "real boy". So you are right that the negative mass virtual particles could be absorbed only as often as the positive mass ones, except that the positive mass ones would leave behind a negative mass partner in the "real world" in order to conserve energy-- and that's disallowed. However, a negative mass particle could fall into the black hole, and the positive mass partner it leaves behind is allowed and can balance its energy by the lost energy by the black hole. It's a selection rule, then.

So in short, the asymmetry you are asking about stems from the asymmetry that positive mass virtual particles can become real on our side of the event horizon, but the negative mass ones cannot. Why the rules are different on the other side of the event horizon, I have no idea, but a lot is different over there!

Delvo
2008-Oct-14, 06:18 PM
3) the energy to create the particles was borrowed from the BH's gravityHow does THAT part work?