6 ms·

The odds that cold fusion has been discovered are 0.

jacobwilliamroy 6y ago
I really think cold fusion is a prank. Like when my dad would send me out to buy "headlight fluid" just to mess with me.
- dumbfoundded 6y ago
  I think it's like trying to prove P = NP. Maybe it's technically possible, but no one in their right mind thinks it's going to happen.
  - jacobwilliamroy 6y ago
    As far as I can tell, the only reason cold fusion is even a thing is because someone published a paper that has never been reproduced. P=NP is at least possible: it has to be true or untrue. I'm not even sure if our current understand of physics even supports cold fusion. I guess maybe it does seeing as how I got downvoted? Presumably by amazing scientists who have developed cold fusion technology? Or at least have a theory of how it could happen in our universe?
    - Retric 6y ago
      Muon-catalyzed fusion is beloved to be physically possible at room temperature though as the catalyst has a half life of ~ 2.2 microseconds that’s not practical. But as far as we know cold fusion as described in the original paper is simply a mistake in the original experiment.
    - hansvm 6y ago
      Fwiw, P=NP could be independent from our current commonly used axioms; it doesn't have to be purely true or false.
      - versteegen 6y ago
        My understanding is it's necessarily either true or false, but may not be provably true or false. This could allow us to actually have an algorithm that solves all NP problems in P time, but ZFC can't prove it works for all inputs. Edit: So in that case, what would it mean to add an axiom that P=NP? See https://mathoverflow.net/questions/50023/independence-of-p-np https://mathoverflow.net/questions/50023/independence-of-p-n... especially the answer by Andreas Blass. Basically, you could add axioms that change the meaning of 'Turing machine' (ie 'computation') by changing the meaning of 'natural number' resulting in an algorithm witnessing P=NP that maybe can't be run on physical computers. Way off topic...
        hansvm 6y ago
        Agreed, definitely off topic. Fun to consider anyway :) Without considering many facts specific to P=NP, it could be feasible for it to neither true nor false in ZFC (i.e., some model of ZFC has P=NP, and some other has P!=NP), in which case you could take P=NP as another axiom. Other statements that work this way include the continuum hypothesis. If I'm not mistaken (and misstatements regarding P=NP are common, so don't take this blindly), P=NP has a substantial amount of additional structure to it due to it being a low-complexity arithmetical statement. In particular, I believe you're correct that in ZFC it is actually either true or false in all models, but not necessarily provably so from within ZFC. In this case you could try to take it as an axiom (e.g. ZFC+PNP), but you'd either wind up with ZFC itself or an inconsistent axiom set. As a related (maybe equivalent?) statement, P=NP has the property that if A is an axiom independent from ZF and P=NP (resp P!=NP) is provable in ZF+A then P=NP (resp P!=NP) is provable in ZF, again due to its nature as a low-complexity arithmetical statement, so either P=NP is unprovable in any meaningful extension of ZF, or it's provable in all of them.
    - pfdietz 6y ago
      The weird thing about the field is that a negative result should REDUCE the estimate of how likely something is. And yet, after P&F, people took it more seriously.
      - nextaccountic 6y ago
        P&F?
        pfdietz 6y ago
        Pons and Fleischmann.
beervirus 6y ago
Lattice assisted nuclear reactions exist. They just don't generate usable amounts of power.
- gus_massa 6y ago
  > Lattice assisted nuclear reactions exist. "Lattice assisted nuclear reactions" is just another name for "cold fusion" (or perhaps a branch of "cold fusion"). All the papers published about this have been unconvincing. > They just don't generate usable amounts of power. All the papers I remember report an small excess of heat. The problem is that heat is very difficult to measure accurately (the different parts of the equipment have different temperatures, estimating the heat transported in convection is a mess, some chemical parts may react, ...)
  - lumost 6y ago
    There are strong theoretical grounds for lattice assisted fusion. The metal lattice acts to screen the deuterium atoms, and the lattice increases the overall cross section. https://www.sciencedirect.com/science/article/abs/pii/S0168583X17306286 https://www.sciencedirect.com/science/article/abs/pii/S01685... Unfortunately no practical mechanism for creating a self sustaining reaction has been proposed. Although the theoretical benefit has been demonstrated by heating the fuel via hot neutron bombardment. https://journals.aps.org/prc/abstract/10.1103/PhysRevC.101.044609 https://journals.aps.org/prc/abstract/10.1103/PhysRevC.101.0...
    - gus_massa 6y ago
      The articles are interesting, but in both case it is not enough the 400°C that they used in this experiment. I think that "cold fusion" is not theoretically impossible. For comparison, "high temperature superconductivity" is also weird, and in 1985 any result about it would have been received with a big dose od skepticism. The problem is that "cold fusion" has a very bad track record in the last years.

I really think cold fusion is a prank. Like when my dad would send me out to buy "headlight fluid" just to mess with me.

dumbfoundded 6y ago
I think it's like trying to prove P = NP. Maybe it's technically possible, but no one in their right mind thinks it's going to happen.
- jacobwilliamroy 6y ago
  As far as I can tell, the only reason cold fusion is even a thing is because someone published a paper that has never been reproduced. P=NP is at least possible: it has to be true or untrue. I'm not even sure if our current understand of physics even supports cold fusion. I guess maybe it does seeing as how I got downvoted? Presumably by amazing scientists who have developed cold fusion technology? Or at least have a theory of how it could happen in our universe?
  - Retric 6y ago
    Muon-catalyzed fusion is beloved to be physically possible at room temperature though as the catalyst has a half life of ~ 2.2 microseconds that’s not practical. But as far as we know cold fusion as described in the original paper is simply a mistake in the original experiment.
  - hansvm 6y ago
    Fwiw, P=NP could be independent from our current commonly used axioms; it doesn't have to be purely true or false.
    - versteegen 6y ago
      My understanding is it's necessarily either true or false, but may not be provably true or false. This could allow us to actually have an algorithm that solves all NP problems in P time, but ZFC can't prove it works for all inputs. Edit: So in that case, what would it mean to add an axiom that P=NP? See https://mathoverflow.net/questions/50023/independence-of-p-np https://mathoverflow.net/questions/50023/independence-of-p-n... especially the answer by Andreas Blass. Basically, you could add axioms that change the meaning of 'Turing machine' (ie 'computation') by changing the meaning of 'natural number' resulting in an algorithm witnessing P=NP that maybe can't be run on physical computers. Way off topic...
      - hansvm 6y ago
        Agreed, definitely off topic. Fun to consider anyway :) Without considering many facts specific to P=NP, it could be feasible for it to neither true nor false in ZFC (i.e., some model of ZFC has P=NP, and some other has P!=NP), in which case you could take P=NP as another axiom. Other statements that work this way include the continuum hypothesis. If I'm not mistaken (and misstatements regarding P=NP are common, so don't take this blindly), P=NP has a substantial amount of additional structure to it due to it being a low-complexity arithmetical statement. In particular, I believe you're correct that in ZFC it is actually either true or false in all models, but not necessarily provably so from within ZFC. In this case you could try to take it as an axiom (e.g. ZFC+PNP), but you'd either wind up with ZFC itself or an inconsistent axiom set. As a related (maybe equivalent?) statement, P=NP has the property that if A is an axiom independent from ZF and P=NP (resp P!=NP) is provable in ZF+A then P=NP (resp P!=NP) is provable in ZF, again due to its nature as a low-complexity arithmetical statement, so either P=NP is unprovable in any meaningful extension of ZF, or it's provable in all of them.
  - pfdietz 6y ago
    The weird thing about the field is that a negative result should REDUCE the estimate of how likely something is. And yet, after P&F, people took it more seriously.
    - nextaccountic 6y ago
      P&F?
      - pfdietz 6y ago
        Pons and Fleischmann.

beervirus 6y ago

Lattice assisted nuclear reactions exist. They just don't generate usable amounts of power.

gus_massa 6y ago
> Lattice assisted nuclear reactions exist. "Lattice assisted nuclear reactions" is just another name for "cold fusion" (or perhaps a branch of "cold fusion"). All the papers published about this have been unconvincing. > They just don't generate usable amounts of power. All the papers I remember report an small excess of heat. The problem is that heat is very difficult to measure accurately (the different parts of the equipment have different temperatures, estimating the heat transported in convection is a mess, some chemical parts may react, ...)
- lumost 6y ago
  There are strong theoretical grounds for lattice assisted fusion. The metal lattice acts to screen the deuterium atoms, and the lattice increases the overall cross section. https://www.sciencedirect.com/science/article/abs/pii/S0168583X17306286 https://www.sciencedirect.com/science/article/abs/pii/S01685... Unfortunately no practical mechanism for creating a self sustaining reaction has been proposed. Although the theoretical benefit has been demonstrated by heating the fuel via hot neutron bombardment. https://journals.aps.org/prc/abstract/10.1103/PhysRevC.101.044609 https://journals.aps.org/prc/abstract/10.1103/PhysRevC.101.0...
  - gus_massa 6y ago
    The articles are interesting, but in both case it is not enough the 400°C that they used in this experiment. I think that "cold fusion" is not theoretically impossible. For comparison, "high temperature superconductivity" is also weird, and in 1985 any result about it would have been received with a big dose od skepticism. The problem is that "cold fusion" has a very bad track record in the last years.