What Is Zero-Point Energy?

[bobthedrummer]

http://www.calphysics.org/research.html

Sailing The Sea Of Energy (Click on the new energy topic-it leads to zero-point)
http://www.altenergy.org/home/homeframeset.html

[GAspnes]

1. that first site is pretty good

but the problem I have with zero-point energy is that it's something for nothing. Except for Hawking radiation, there doesn't seem to be any way to capture the virtual energy for longer than Plank time.

[Bernardo de La Paz]

2. Zero Point energy

Zero Point energy is an interesting concept that there may be a large amount of energy available for free from the quantum nature of matter and the universe at every point. The links you give gloss over some of the details, distort others, and mis-interpret some. For example it says that "there is more than enough energy in the volume of a coffee cup to evaporate all the world's oceans". This is true, but would take a lot of energy to release it, and the calculation referred to is not a zero point energy calculation.

It is an interesting concept, but it is not something to invest in this decade. At this point, as an investment concept, it is indistinguishable from perpetual motion machines, for now. Save your money.

[papau]

4. I believe you need Zero Point energy for the Big Bang creation story?

?

:-)

[GAspnes]

5. or branes (n/t)

[papau]

8. But Hawking just said Branes (multiple universe) is out?

Bit I like it while it lasted!

http://www.sciencenews.org/articles/20010922/bob9.asp

:-)

[phantom power]

10. I don't think Hawking's results disprove brane models

What Hawking said was that information that enteres a black hole stays in this universe.

I don't think that bears one way or the other on the viability of brane theories.

[papau]

12. either/or?granted the equations are not yet published -and granted I am at

the point in life where I doubt I could get through them - but the explanation I heard was a qm that did not "need" multiple universes.

SO multiple universe was a need developed via Bell in 63, but is now needed only for brane models in multiple dimensions is so as to kick off the big bang?

not much of a need when we have God! or zero point energy!

:-) just having a bit of fun shaking this DU thread! :-)

:toast:

:party:

:-)

[Dudley_DUright]

3. Extracting usuable energy from quantum mechanical zero-point

motion is as scientifically credible as extracting usuable energy from "cold fusion" (which you may note is the topic immediately above zero-point energy at the altenergy website).

This is a reasonably good introduction to what Zero-point energy is:

http://en.wikipedia.org/wiki/Zero-point_energy

[Dogmudgeon]

6. Shh! Don't tell Drs. Casimir or Cherenkov!

Yes, Cherenkov radiation and the Casimir Effect are forms of "Zero-Point" energy that can be "extracted" to do measurable work. Experimentation and development is well under way.

The Wikipedia article is good, but experiments done over the last year have firmed up the ZPE/Casimir connection.

There are plenty of wackos who pretend to be ZPE researchers, but there are plenty of The Real Thing, too. The word "Quantum" is similarly misused, but it's still a real branch of physics.

--bkl

[GAspnes]

7. I don't get the connection between Cherenkov radiation & ZPE

The Casimir effect is due to unbalancing quantum fluctuation pressure when a small cavity is created between two perfectly flat surfaces, so you get energy out ('work') as the two surfaces are pushed together. Then you have to put energy in ('unwork') to separate them again. There's no net energy gain from the Casimir effect and there will be a net loss since the equipment must be cryogenically cooled to overcome room tempurature Brownian fluctuations.

But how is Cherenkov radiation due to zero-point energy?

[bobthedrummer]

9. We really know very little about gravity, that seems to be obvious to this

layperson. Mr. Hawking's recent statements about black hole theory supports my view-we don't know very much about gravity at all.

[phantom power]

11. There are some fundamenal open questions

(1) Why is gravitational mass equivalent to inertial mass?

(2) What is responsible for inertia? Or mass, or gravitation, for that matter.

We know a lot about gravity, but most of what we know about gravitation is descriptive. Unlike other forces, we have not observed any particle that mediates this force.

I bet there are other good questions I've never heard about.

[bobthedrummer]

13. I know there is anti-gravity, intuitively, lol!

[DrWeird]

14. Consider the energy diagram of a vibrating covalent bond.

Plenty of other things work too, but since I'm not very good at quantum mechanics, let's consider and actual well where the height of the well corresponds with energy (ie the very bottom of the well is zero energy), and the well-digger Elwood.

Now, if this were a classical well, there'd be a rope with a bucket on it that could be lowered to any given depth. But we're dealing with quantum mechanics, so Elwood is inside the well, not on a rope, but on a ladder. Now, as Elwood moves up and down the later he can only take one step at a time. He can't take half a step, or three-quarters of a step, he is ONLY allowed to take one step at a time (or multiple steps, as long as they're integers), no ifs ands or buts, OSHA regulations.

Now, if you give Elwood energy, he'll heat up. That is, he'll climb up the ladder. Give him enough energy and he'll go right out the top, the bond will break, the atom get knocked out the shell, Elwood will be a free particle to go wondering around until he finds another well to fall down into.

Conversely, we could cool Elwood off, in which case he'll descend the ladder. We can make Elwood do work, let's say we want five steps of energy, so we take five steps from Elwood, do work with it, and Elwood will descend five steps (ignoring entropy.)

OK so far? OK, let's say we want to cool Elwood down to absolute zero, take all the energy we can from him so he'll be completely out of energy and at the bottom of the well. So we take energy from Elwood and he descends a step at a time. He gets to the last rung of the ladder above the bottom, and much to his surprise some cheeky bastard as sawed off the last couple of inches of his ladder.

So Elwood is stuck half a step above zero energy, he can't go any lower because it's half a step. This is zero point energy. He's still got some energy, but you can't take it away. This is why at absolute zero particles still have motion. Can you do work with it? No, since you can't take it away.