Okay, lets see if I understand this right.
A vacuum is what is left over when all matter is removed, but technically its not a vacuum in the sense there's nothing there. The Void, or empty space time, is a sea of potential energy, coming and going out of existence in very short times and spaces but in great amounts. We can notice this by the effect it has on small particles such as electrons moving through the Void. Some believe quantum fluctuation in this way may have been the initial energy burst and inflation that started our universe.
How far off am I?
Um... Let me get back to you on that one. Im'a have to do some digging.
That bad, huh? :/
Probably not, it's just a little outside my comfort zone. I'll call for backup, we'll see what comes of it.
Lemme try ... this is just what I heard from my friend the theoretical physicist, so I may have remembered it wrong.
So you have this vacuum and there's nothing there. But you also have quantum uncertainty, and that means there is a small statistical chance for a particle to suddenly pop into existence for a very short amount of time. Because of the fucked up ness of quantum stuff, you can see this as a particle and an anti particle, and when the two meet eachother they dissolve. The uncertainty bit just gives a very small chance that, instead of both not existing and doing this at the same spot, for a few short moments they randomly both exist at slightly separated locations.
Or something like that. It's all very weird and counter intuitive. I think of it like that quantum uncertainty sort of "borrows" a particle from the vacuum and has to pay that back with an anti particle in a way.
Now, you'd think this is a zero-sum game and in the end nothing really happens. But for some strange reason this is not the case, as the simple fact that there's a chance that this happens, and it does happen, even if in the end nothing changed, stuff that is happening causes some kind of "vacuum pressure" to appear. I have no idea what this vacuum pressure does, however.
And yes, afaik, this is one of the theories about what might have set off the Big Bang.
The only thing about your explanation that I'm not entirely sure of is the bit where you say the void is teeming with potential energy. I'm not sure if that's the case. It's teeming with vacuum pressure, but it's not that wild.
But I'm not sure. I can only be vague about this, because frankly I have no idea what I'm talking about, just rehashing what my friend told me, but since I never did the math, I can't say I really get what is going on.
I'll try to direct my friend to this thread, though.
I'm not quite sure what you mean by vacuum pressure.
When I say "potential energy", I mean "energy that has the potential to manifest as matter". It's really hard to imagine energy existing as apart from matter, but that seems to be what is happening in the case of quantum fluctuations, or otherwise it wouldn't happen. The potential energy of a vacuum then becomes something that isn't real in the measurable sense, except when it becomes manifest as short lived particles and their effects on matter.
If I'm wrong, does that mean that energy truly just comes out of nothing? Energy manifests out of nothing for a minute fraction of a second as particles and antiparticles and then is gone?
In addition to the position/momentum uncertainty relation, there is also an energy/time one. So a state that only exists for a short (and therefore more definite) time cannot have a definite energy.
So yes, as long as it comes and goes fast enough, energy can come from nothing.
If that's true, it doesn't make any fucking sense at all. :sad:
It's pretty essential to quantum field theory. In QFT forces are described by particles being exchanged. So two electrons come toward each other, and by exchanging a photon, they are repelled and move off in opposite directions.
That photon is usually described as virtual. It just pops into existence long enough to perform that task and then blips out again. Apparently, some people would say that all photons are virtual, the only distinction being between a photon that gets detected and one that doesn't. Mathematically, they're all equivalent. Like in most of QM, it's our definition of reality that's weak here.
..I'm not helping much here, am I?
I honestly wonder if I'm even capable of understanding this stuff.
And if I'm not capable, I wonder if everyone who says they /really/ understand it isn't just fooling themselves.
Quote from: Kai on August 07, 2009, 11:19:16 PM
I'm not quite sure what you mean by vacuum pressure.
me neither, sorry, all I remember is that something was going on that was called vacuum pressure.
Quote from: Kai on August 07, 2009, 11:29:20 PM
When I say "potential energy", I mean "energy that has the potential to manifest as matter".
but all energy has that potential?
Quote from: Kai on August 08, 2009, 02:12:26 AM
I honestly wonder if I'm even capable of understanding this stuff.
And if I'm not capable, I wonder if everyone who says they /really/ understand it isn't just fooling themselves.
The first line of the first page of your QM notes is that we don't fully understand it, its just something that has to be accepted as some of its aspects can be observed(mathematically). And it is generally our way of interpreting it that creates the problems.
The photons coming into existence just long enough to act as the repelling force between particles is interesting because the effect of them not being canceled out must come from somewhere. If they behave like proper charges then its possible that polarization could cause a separation between the two enough to stop them canceling. But that's a stab in the dark.
I think I understand the Particle repultion via protons part. In that case the energy of the proton is manifest of the relationship between the two particles. However, its this "particles popping in and out of existence in a vacuum" thing that I'm having trouble with.
Star trek style metaphor: when you average out random noise it generally goes to zero. well the popping in and out of existence could be like the background noise upon which everything else rest, it also goes to zero when averaged
Quote from: ☂Faust☂ on August 08, 2009, 02:29:27 PM
Star trek style metaphor: when you average out random noise it generally goes to zero. well the popping in and out of existence could be like the background noise upon which everything else rest, it also goes to zero when averaged
So, the universe has "background noise", but it averages out to zero, so we don't have to explain why its there?
This is of course not related to continuing photons like the microwave background radiation.
Quote from: Kai on August 08, 2009, 02:33:56 PM
Quote from: ☂Faust☂ on August 08, 2009, 02:29:27 PM
Star trek style metaphor: when you average out random noise it generally goes to zero. well the popping in and out of existence could be like the background noise upon which everything else rest, it also goes to zero when averaged
So, the universe has "background noise", but it averages out to zero, so we don't have to explain why its there?
This is of course not related to continuing photons like the microwave background radiation.
No It was directly addressing the photons coming into existence as both a photon and its opposite are created giving an overall of zero if combined. And its not about explaining why its there, the whole line of thought arose from how electrons deflect each other without making physical contact.
Its explained as a photon passing between the two changing the overall momentum of each.
The virtual photon thing came about from a line of thought addressing the "well how does an electron know to emit the photon", so it concluded that it is constantly emitting and reabsorbing photons.
Everything beyond that gets really sketchy.
so, matter is constantly emmitting and reabsorbing these short lived energy partcles and the particles are blinking in and out of existence in pairs on their own and this whole universe is just this giant canvas where stuff happens on and we can't possibly understand what the hell is going on except by our fragmented filtered observations, which really don't help much.
In order for there to be an average of zero, wouldn't half of the particles have to have negative mass-energy?
Also, seems like this has something to do with Hawking radiation.
They don't average to zero. There is always an energy associated with a region of space, even if it completely empty. It's called the vacuum energy and it might be one of the reasons why the expansion of the universe is accelerating.
Hawking radiation happens when a particle/antiparticle pair is created near the event horizon of a black hole. One of the pair is close enough to be sucked in, but the other escapes. It can't get annihilated now, so it acts like a normal particle. This makes it look like the black hole is emitting particles (Hawking radiation). It causes black holes to eventually "evaporate". This process gets faster and faster since smaller black holes evaporate faster.
Quote from: Kai on August 08, 2009, 02:46:38 PM
so, matter is constantly emmitting and reabsorbing these short lived energy partcles and the particles are blinking in and out of existence in pairs on their own and this whole universe is just this giant canvas where stuff happens on and we can't possibly understand what the hell is going on except by our fragmented filtered observations, which really don't help much.
Ladies and gentlemen, theoretical physics! :lulz:
Quote from: Igor on August 08, 2009, 04:08:00 PM
They don't average to zero. There is always an energy associated with a region of space, even if it completely empty. It's called the vacuum energy and it might be one of the reasons why the expansion of the universe is accelerating.
Hah! I knew this energy out of nothing thing was BS. Particles out of unobservable energy, maybe, but not energy out of nothing.
Quote from: Igor on August 08, 2009, 04:08:00 PM
Hawking radiation happens when a particle/antiparticle pair is created near the event horizon of a black hole. One of the pair is close enough to be sucked in, but the other escapes. It can't get annihilated now, so it acts like a normal particle. This makes it look like the black hole is emitting particles (Hawking radiation). It causes black holes to eventually "evaporate". This process gets faster and faster since smaller black holes evaporate faster.
But if the black hole is decreasing in mass, doesn't that mean the particles have negative mass-energy?
Quote from: Kai on August 08, 2009, 04:43:35 PM
Quote from: Igor on August 08, 2009, 04:08:00 PM
They don't average to zero. There is always an energy associated with a region of space, even if it completely empty. It's called the vacuum energy and it might be one of the reasons why the expansion of the universe is accelerating.
Hah! I knew this energy out of nothing thing was BS. Particles out of unobservable energy, maybe, but not energy out of nothing.
Well no. The vacuum energy arises from the fact that the virtual particles don't average to zero. The energy is the result of the particles, not the other way round.
Quote from: Jerry_Frankster on August 08, 2009, 05:10:00 PM
Quote from: Igor on August 08, 2009, 04:08:00 PM
Hawking radiation happens when a particle/antiparticle pair is created near the event horizon of a black hole. One of the pair is close enough to be sucked in, but the other escapes. It can't get annihilated now, so it acts like a normal particle. This makes it look like the black hole is emitting particles (Hawking radiation). It causes black holes to eventually "evaporate". This process gets faster and faster since smaller black holes evaporate faster.
But if the black hole is decreasing in mass, doesn't that mean the particles have negative mass-energy?
No again, It's just the same as someone in a balloon throwing weights out of the basket. The balloon gets lighter and rises, but the weights don't need to have negative energy.
Quote from: Igor on August 08, 2009, 06:27:19 PM
Quote from: Kai on August 08, 2009, 04:43:35 PM
Quote from: Igor on August 08, 2009, 04:08:00 PM
They don't average to zero. There is always an energy associated with a region of space, even if it completely empty. It's called the vacuum energy and it might be one of the reasons why the expansion of the universe is accelerating.
Hah! I knew this energy out of nothing thing was BS. Particles out of unobservable energy, maybe, but not energy out of nothing.
Well no. The vacuum energy arises from the fact that the virtual particles don't average to zero. The energy is the result of the particles, not the other way round.
then where do the virtual particles come from? don't say particles, cause there aren't any in a virtual vacuum
Um... As far as I can tell, they come from nothing.
Not exactly satisfying, but that's the universe for you.
Actually, maybe I can explain this better.
In classical physics, there's the harmonic oscillator. Which can describe a pendulum, a weight and a spring, etc. When you analyse a system like this using quantum mechanics, you discover that there is a lowest possible energy, usually called the "zero-point energy".
Now, the fields that describe different particles and their interactions can be modelled as a big square grid of springs and weights, all attached to each other. So if you displace one weight and then let go, the disturbance will propagate outwards. This just describes particle, travelling. But since this is quantum, there is a lowest possible energy. There is always some disturbance.
Which I think means that the vacuum energy and the virtual particles are the same thing, neither one causing the other.
Quote from: Igor on August 08, 2009, 06:27:19 PM
No again, It's just the same as someone in a balloon throwing weights out of the basket. The balloon gets lighter and rises, but the weights don't need to have negative energy.
So mass is escaping from inside the event horizon?
Quote from: Igor on August 08, 2009, 06:40:22 PM
Um... As far as I can tell, they come from nothing.
Not exactly satisfying, but that's the universe for you.
Quotethe vacuum energy and the virtual particles are the same thing, neither one causing the other
So, its just latent energy that happens to manifest as matter.
Actually, that's rather satisfying, and fits in with my worldview quite nicely. It might be made up bullshit still, but its okay made up bullshit.
Quote from: Jerry_Frankster on August 08, 2009, 08:03:24 PM
Quote from: Igor on August 08, 2009, 06:27:19 PM
No again, It's just the same as someone in a balloon throwing weights out of the basket. The balloon gets lighter and rises, but the weights don't need to have negative energy.
So mass is escaping from inside the event horizon?
I thought that was negative mass getting stuck inside the event horizon?
Yeah, Regret is right, I got confused there. One particle has negative energy and goes in, the other is positive and gets emitted as the Hawking radiation.
Which makes no sense if I want the vacuum energy to average to nonzero...
Aaaaaaaagh :asplode:
Quote from: Igor on August 08, 2009, 08:35:15 PM
Yeah, Regret is right, I got confused there. One particle has negative energy and goes in, the other is positive and gets emitted as the Hawking radiation.
Which makes no sense if I want the vacuum energy to average to nonzero...
Aaaaaaaagh :asplode:
maybe it averages to zero everywhere except around a high gravity source.
why do you want the vacuum energy to do anything?
Well not that I wanted it to, more that reading about it suggests that it should.
Quote from: Jerry_Frankster on August 08, 2009, 03:54:44 PM
In order for there to be an average of zero, wouldn't half of the particles have to have negative mass-energy?
Also, seems like this has something to do with Hawking radiation.
or be out of phase because of the wave/particle nature.
Quote from: Kai on August 08, 2009, 08:26:14 PM
Quote from: Igor on August 08, 2009, 06:40:22 PM
Um... As far as I can tell, they come from nothing.
Not exactly satisfying, but that's the universe for you.
Quotethe vacuum energy and the virtual particles are the same thing, neither one causing the other
So, its just latent energy that happens to manifest as matter.
Actually, that's rather satisfying, and fits in with my worldview quite nicely. It might be made up bullshit still, but its okay made up bullshit.
yeah thats a nice way of looking at it.
As a kid did you ever do the piece of string thing where you put lots of loops in it but dont thread it, when you pull the string the loops all vanish.
All the mass in the universe probably has its its opposite somewhere and could eventually neutralize to a nice harmonious nothing.
Blegh, harmony.
also,
:asplode:
Bump: as a reminder since it's a monday.