3 ms·

I think I'd have to agree with you in general, but I'd also have to admit that things start making me do a double take when you get down to the forces from the

I think I'd have to agree with you in general, but I'd also have to admit that things start making me do a double take when you get down to the forces from the casimir effect in the nanometer range between uncharged conductors that make me think it would be in the realm of QFT for one much more versed than I am to come up with some theoretical frame work that millennia from now would be considered basic knowledge like conservation of energy was once thought of in the past…

lutusp 13y ago
> ... things start making me do a double take when you get down to the forces from the casimir effect ... Yes, but static forces don't require energy. Only when force and motion are combined is an energy expenditure required. Remember that Casimir effect measurements are carried out by applying an external force to move two plates together, which means the initial energy of motion comes from elsewhere, not from the virtual realm.
- cinquemb 13y ago
  > Remember that Casimir effect measurements are carried out by applying an external force to move two plates together So an external field not under control cannot be present (i.e. the experimenter is not putting more energy into the system) to obtain measurements?
  - lutusp 13y ago
    My only point was that the Casimir Effect doesn't represent the harvesting of energy, only force, force isn't energy, therefore the effect doesn't violate energy conservation. This is consistent with both quantum theory, in which virtual particles can't unbalance nature's account books, and energy conservation, a principle that stands at the center of most present physical theories. Here's an example: http://arachnoid.com/conservation_of_energy/#Planetary_Orbit_Example http://arachnoid.com/conservation_of_energy/#Planetary_Orbit...
    - cinquemb 13y ago
      I don't think the PDF was saying that it could violate energy conservation, nor was the actual content implying something from nothing (the title did though), but it did imply that there is a possibility that the forces present in an existing system (i.e. non conducting plates within a region of space under the influence of an external field), could be transferred to a much smaller system without the experimenter using energy to apply a force. I think that because something else is going on that can't be explained for, is the reason why people are looking in the first place. Here's an example of that[0]: "Surprisingly, with pyrrole the predicted ‘activation barriers’ were way out, with calculations “less than a third of the measured value”. After much head scratching, puzzled scientists turned to a purely quantum phenomenon called ‘zero-point energy’. In classical physics, an object losing energy can continue to do so until it can be thought of as sitting perfectly still. In the quantum world, this is never the case: everything always retains some form of residual – even undetectable – energy, known as ‘zero-point energy’. While ‘zero-point energy’ is well known to be associated with motion of the atoms contained in molecules, it was previously believed that such tiny amounts of energy simply don’t affect the molecule as a whole to any measurable extent, unless the molecule broke apart. But now, the researchers have discovered that the “quantum nature” of the molecule's internal motion actually does affect the molecule as a whole as it moves across the surface, defying the ‘classical’ laws that it’s simply too big to feel quantum effects." [0] http://www.cam.ac.uk/research/news/movement-of-pyrrole-molecules-defy-classical-physics http://www.cam.ac.uk/research/news/movement-of-pyrrole-molec...
      - lutusp 13y ago
        > But now, the researchers have discovered that the “quantum nature” of the molecule's internal motion actually does affect the molecule as a whole as it moves across the surface, defying the ‘classical’ laws that it’s simply too big to feel quantum effects." Well, first, Heisenberg's uncertainly principle doesn't place an upper bound on the size of a mass susceptible to quantum effects, only the probability. An easy way to picture this is to say that flipping a fair coin once has equal probability to come up heads (1) or tails (0). But for a single flip, 1/2 is not a possible outcome. For a million coin flips, an averaged result of 1 or 0 is still a possibility, but it is extremely unlikely, whereas an averaged outcome of 1/2, which was impossible for a single coin flip, is now rather likely. This means there is no mass or size threshold for quantum effects, as many people think -- the effects just become less apparent. But it's important to distinguish between quantum effects and energy state. If a system's wave function collapses and a superposition of states becomes one state, that state cannot have more or less energy than any other possible state. Expressed another way, if you open Schrödinger's box and the cat is dead, the dead cat can't have more or less energy than the living cat. The bottom line is that quantum theories don't violate energy conservation, and all the talk about ZPE leading to spacecraft drives arises from people who don't understand physics. > "... defying the ‘classical’ laws that it’s simply too big to feel quantum effects." This is a case of a journalist who also doesn't understand quantum theory. No classical laws are being defied, and there is no mass so big that it cannot experience quantum effects. The reason is easy to explain -- a huge mass is composed of individual atoms, and individual atoms experience quantum effects. Q.E.D. :)

lutusp 13y ago

> ... things start making me do a double take when you get down to the forces from the casimir effect ... Yes, but static forces don't require energy. Only when force and motion are combined is an energy expenditure required. Remember that Casimir effect measurements are carried out by applying an external force to move two plates together, which means the initial energy of motion comes from elsewhere, not from the virtual realm.

cinquemb 13y ago
> Remember that Casimir effect measurements are carried out by applying an external force to move two plates together So an external field not under control cannot be present (i.e. the experimenter is not putting more energy into the system) to obtain measurements?
- lutusp 13y ago
  My only point was that the Casimir Effect doesn't represent the harvesting of energy, only force, force isn't energy, therefore the effect doesn't violate energy conservation. This is consistent with both quantum theory, in which virtual particles can't unbalance nature's account books, and energy conservation, a principle that stands at the center of most present physical theories. Here's an example: http://arachnoid.com/conservation_of_energy/#Planetary_Orbit_Example http://arachnoid.com/conservation_of_energy/#Planetary_Orbit...
  - cinquemb 13y ago
    I don't think the PDF was saying that it could violate energy conservation, nor was the actual content implying something from nothing (the title did though), but it did imply that there is a possibility that the forces present in an existing system (i.e. non conducting plates within a region of space under the influence of an external field), could be transferred to a much smaller system without the experimenter using energy to apply a force. I think that because something else is going on that can't be explained for, is the reason why people are looking in the first place. Here's an example of that[0]: "Surprisingly, with pyrrole the predicted ‘activation barriers’ were way out, with calculations “less than a third of the measured value”. After much head scratching, puzzled scientists turned to a purely quantum phenomenon called ‘zero-point energy’. In classical physics, an object losing energy can continue to do so until it can be thought of as sitting perfectly still. In the quantum world, this is never the case: everything always retains some form of residual – even undetectable – energy, known as ‘zero-point energy’. While ‘zero-point energy’ is well known to be associated with motion of the atoms contained in molecules, it was previously believed that such tiny amounts of energy simply don’t affect the molecule as a whole to any measurable extent, unless the molecule broke apart. But now, the researchers have discovered that the “quantum nature” of the molecule's internal motion actually does affect the molecule as a whole as it moves across the surface, defying the ‘classical’ laws that it’s simply too big to feel quantum effects." [0] http://www.cam.ac.uk/research/news/movement-of-pyrrole-molecules-defy-classical-physics http://www.cam.ac.uk/research/news/movement-of-pyrrole-molec...
    - lutusp 13y ago
      > But now, the researchers have discovered that the “quantum nature” of the molecule's internal motion actually does affect the molecule as a whole as it moves across the surface, defying the ‘classical’ laws that it’s simply too big to feel quantum effects." Well, first, Heisenberg's uncertainly principle doesn't place an upper bound on the size of a mass susceptible to quantum effects, only the probability. An easy way to picture this is to say that flipping a fair coin once has equal probability to come up heads (1) or tails (0). But for a single flip, 1/2 is not a possible outcome. For a million coin flips, an averaged result of 1 or 0 is still a possibility, but it is extremely unlikely, whereas an averaged outcome of 1/2, which was impossible for a single coin flip, is now rather likely. This means there is no mass or size threshold for quantum effects, as many people think -- the effects just become less apparent. But it's important to distinguish between quantum effects and energy state. If a system's wave function collapses and a superposition of states becomes one state, that state cannot have more or less energy than any other possible state. Expressed another way, if you open Schrödinger's box and the cat is dead, the dead cat can't have more or less energy than the living cat. The bottom line is that quantum theories don't violate energy conservation, and all the talk about ZPE leading to spacecraft drives arises from people who don't understand physics. > "... defying the ‘classical’ laws that it’s simply too big to feel quantum effects." This is a case of a journalist who also doesn't understand quantum theory. No classical laws are being defied, and there is no mass so big that it cannot experience quantum effects. The reason is easy to explain -- a huge mass is composed of individual atoms, and individual atoms experience quantum effects. Q.E.D. :)