Ok... Vacuum Energy?

Question

I just read this article pertaining to the Casimir Effect

http://www.daviddarling.info/encyclopedia/C/Casimir.html

It even a container with an "absolute" vacuum would have electromagnetic waves of every wavelength... where do these waves come from?

Are they produced by the surrounding material or would they still be there if we hypothetically had an absolute void?

Best Answer goes to whoever addresses the different aspect of the question(s) the best.

Answer 1

Electromagnetic waves travel across vacuum. They don't need a medium as the carrier. Much of the universe is void of matter and cold. But it is actually filled with electromagnetic waves.

Bright and dark matters emit electromagnetic wave at different frequencies. A human body emits or reflects electromagnetic waves, the visible part of which make it visible in the day, and the infrared part of which make it detectable in the night with a night vision goggle.

We can detect electromagnetic waves coming from all directions in the universe. Microwaves come to the earth in the same intensity in all directions.

If we create an absolute vacuum outside the solar system, there will be energy going through it.

However, if you mean absolute void, the condition before the Big Bang, it would be a different story. There was no space, no time and no energy.

More details are in the book http://en.wikipedia.org/wiki/A_Brief_His...

Answer 2

The energy is produced by pairs of particles that come into existence spontaneously with positive and negative charge. The energy to create them is literally 'borrowed' from the vacuum. The particles travel a distance (usually pretty short) and then collide, destroying each other and repaying the debt to the vacuum.

This constant creation and destruction of particles is what creates the electromagnetic waves. Between the Casimir plates, some of the created particles can escape before reuniting with their counterparts. This decreases the electromagnetic waves and causes the 'negative' pressure that allows the plates to move closer together (as the higher pressure from outside pushes them).

It's theorized that some sort of similar spontaneous particle creation is responsible for the event that resulted in the Big Bang, where energy/matter literally came 'out of nowhere', much to the dismay of those who believe something cannot come out nothing.

Also, 'Hawking Radiation' which is produced in the vicinity of a black hole is believed to be caused when one of a pair of self-created particles ventures over the event horizon, and is swallowed up by the black hole. The other particle remains outside the event horizon, and escapes into space, where it looks like radiation emitted by the black hole.

So, the 'empty' vacuum of space itself creates the particles, and thus the waves that push on the plates. So-called 'empty' space contains a huge amount of vacuum energy, which might be better called 'potential' energy that may have played an important role in the beginning and development of the earliest stages of our Universe.

EDIT: Because of the duality of particles and waves, and because we're talking about electromagnetic fields here, the 'particle' would be more akin to an electron. Quarks are only thought to exist in groups of three; nobody has ever observed a single or double quark as a result of a collision in a particle accelerator, for example.

This process is also known as 'quantum jitters' because of the frenzied activity as particles emerge and vanish.

I see all three current posters have three negative votes each. Some people seem to have trouble understanding the world around them.

Answer 3

The Casimer effect has to do with the creation/anihilation of quantum particles in the universe - doesn't matter if there's a vacuum or not.

It's been seen in labs that a positron/electron pair will suddenly, spontaneously be created - then just as quickly anihilate themselves, leaving a net gain in mas/energy of zero.  This "effect" is what's being described - it's not any particular material that does it - it's just the fabric of our universe.

It'd be cool to tap this energy... but, that would mean that the universe is unstable.

Answer 4

We can observe that vacuum energy exists, indirectly, because it has effects that are in accordance with predictions: the Casimir effect is one such effect. The Lamb shift is another. The effect of quantum tunneling is yet another.

The Lamb shift is a change in the energy of spectral features in starlight caused by an asymmetric encounter between the starlight's photons and virtual electron-positron pairs that occur from pair production in vacuum fluctuations that have energies above ~1 MeV. The brevity of the dipole makes it possible that a passing photon will either go up in energy more than down, or that it will go down in energy more than up, and thus leave the encounter with either (very slightly) more or less energy than it arrived with.

By the way, the most common virtual particles are the little stuff, like electrons and positrons (and maybe neutrinos and anti-neutrinos). Heavier virtual particles probably occur, but less frequently. Universes occur in the same way, but much, much less frequently.

God-believers don't approve of the rejection of the necessity of a "first cause" for universes, which these facts imply. As long as they can pretend that universes require causes, they can assert - quite without evidence - that that cause must be a god, and theirs in particular. So the implication of observed effects, such as the Casimir effect and the Lamb shift, cause them to feel "threatened" with the loss of their faith, or at least with the loss of the popularity of that faith.

But why does vacuum energy exist? Empty space is a ground state, not an existential absolute. The uncertainty principle forbids the permanence of any given state having an action below h-bar, or 1.055E-34 Joule seconds. Even if, at some moment, the energy state is "zero" (or what is locally defined as zero), it must, rather than staying exactly at that constant energy, oscillate randomly around it. The fundamental physical constant, h-bar, is the amplitude of nature's roundoff error, or dark current, or fundamental noise.

There is no place in the universe where you can be at an infinite distance from the nearest mass. Always, there is matter at some finite distance from you, which means that there's a bit of potential energy in space relating you with that other matter. That means that assigning "zero energy" content to a vacuum near yourself is merely to employ the convenience of defining your locality as a ground energy state.

Someone closer to a large mass than you were might define his own locality as his ground energy state and assert that you were "above the zero energy level."

Someone even more remote from matter than you were might suggest that his locality was "zero" and that your position was "below zero," which is to say a position of negative energy.

But, to repeat, all parts of the universe are related to at least some of the other parts by the potential energy that exists in space. A hypothetical person who was at an infinite distance from the nearest other mass (and, strictly speaking, he'd have to be massless himself) would occupy a position energetically above any place within our universe. Of course, he would be unrelated to our universe in every way, being at infinite distance from anything in it.

That does not mean, however, that even this hypothetical observer's locality has an absolutely zero energy level. There's no way to judge such a level in observable terms. Even he can do no better than define his locality as a ground state for his convenience. Fortunately, this is sufficient for anyone to do physics.

Philosophy informs physics in that it provides the lore pertaining to how to do useful thinking. One of the ideas from philosophy is that tautologies are always true. To be sure, most tautologies are trivial things, such as "A thing is itself" or "A is A." But there's one (and perhaps only one) tautology that is not trivial: Existence exists.

Usually, when you say "A is A," you don't mean that there's no such thing as a B. But, in the case of "existence exists," that is exactly what you do mean.

Our customary expression "Nothing does not exist," is not the best way to present the exclusion, since the very word "nothing" becomes a conceptual object, which the exclusion from existence requires there not be. It's better to say "What does not exist...there is no such what." (You'll appreciate that language conventions do not always accord with philosophical rules for useful thinking.)

So "existence exists" is necessarily true. The contrary is not possible. The question to ask, then, is what is the default form that existence takes, when there is no special reason for things to be otherwise. And the answer is: vacuum energy in random distribution and in random flux. And universes occur, either as special events caused by the extreme high end of the spectral distribution in that flux, or by peculiarly large aggregations in spacetime of fluctuations of severally smaller energies.

(P.S. I am not the source of any of the negative votes given to the other posters. I just now gave each of them a positive vote.)