3 ms·

I agree with all your reservations. The article indeed gave no indication of hope on the central problem, obtaining a violation of the weak energy condition. H

by kdavis 13y ago

I agree with all your reservations. The article indeed gave no indication of hope on the central problem, obtaining a violation of the weak energy condition. However, there is a relatively easy way to violate the weak energy condition using binding energy. If one binds M_1 and M_2 with binding energy M_B such that M_B > M_1 + M_2, then one can violate the weak energy condition. I know for a fact that the above inequality is satisfied for some multi-brane configurations in M-Theory. So, there is hope.

Steuard 13y ago
Oh, I certainly won't argue that such progress must be absolutely impossible! The fact that Alcubierre's solution exists at all illustrates how unwise that would be. (I've also heard someone suggest that you might be able to produce an Alcubierre-like configuration if you could make a compact dimension's radius larger within some local region. No idea if there's any sort of duality to the brane configurations you're referring to.) But the point is (and I don't think you'd disagree), if this guy wants to be taken seriously, he needs to tell someone what he's doing. If he thinks that he's creating a system with vast binding energy (greater than mc^2), that would be pretty easy for him to say. If he thinks he's constructing a bound state of branes or manipulating the size of an extra dimension, that would be easy to say, too. And even moderately convincing evidence for any one of those things would immediately make him one of the most famous and respected scientists on the planet: the warp drive aspirations aren't even necessary. The complete lack of such details is a pretty compelling argument that he's not in that position.
- kdavis 13y ago
  > I've also heard someone suggest that you might be able to produce an Alcubierre-like configuration if you could make a compact dimension's radius larger within some local region. Interesting, I hadn't heard of that one. > But the point is (and I don't think you'd disagree), if this guy wants to be taken seriously, he needs to tell someone what he's doing. I agree 100%. PS: In the interest of full disclosure, a lifetime (AKA 14 years) ago, I did some research for NASA looking into such "negative mass solutions" in M-Theory that arise as a result of hep-th/9507022.
  - Steuard 13y ago
    > I did some research for NASA looking into such "negative mass solutions" in M-Theory that arise as a result of hep-th/9507022. Cool! The most informative thing about that to me is simply the knowledge that NASA has a history of investigating this sort of thing. Maybe it's a good thing if they keep a trickle of resources pointed in that direction, just in case there's something really there to be found. I hope they've got good people assessing whether it's worth it. (It's still odd for that sort of speculative work to be getting substantial press attention, though.)

by kdavis 13y ago

Steuard 13y ago

Oh, I certainly won't argue that such progress must be absolutely impossible! The fact that Alcubierre's solution exists at all illustrates how unwise that would be. (I've also heard someone suggest that you might be able to produce an Alcubierre-like configuration if you could make a compact dimension's radius larger within some local region. No idea if there's any sort of duality to the brane configurations you're referring to.) But the point is (and I don't think you'd disagree), if this guy wants to be taken seriously, he needs to tell someone what he's doing. If he thinks that he's creating a system with vast binding energy (greater than mc^2), that would be pretty easy for him to say. If he thinks he's constructing a bound state of branes or manipulating the size of an extra dimension, that would be easy to say, too. And even moderately convincing evidence for any one of those things would immediately make him one of the most famous and respected scientists on the planet: the warp drive aspirations aren't even necessary. The complete lack of such details is a pretty compelling argument that he's not in that position.

kdavis 13y ago
> I've also heard someone suggest that you might be able to produce an Alcubierre-like configuration if you could make a compact dimension's radius larger within some local region. Interesting, I hadn't heard of that one. > But the point is (and I don't think you'd disagree), if this guy wants to be taken seriously, he needs to tell someone what he's doing. I agree 100%. PS: In the interest of full disclosure, a lifetime (AKA 14 years) ago, I did some research for NASA looking into such "negative mass solutions" in M-Theory that arise as a result of hep-th/9507022.
- Steuard 13y ago
  > I did some research for NASA looking into such "negative mass solutions" in M-Theory that arise as a result of hep-th/9507022. Cool! The most informative thing about that to me is simply the knowledge that NASA has a history of investigating this sort of thing. Maybe it's a good thing if they keep a trickle of resources pointed in that direction, just in case there's something really there to be found. I hope they've got good people assessing whether it's worth it. (It's still odd for that sort of speculative work to be getting substantial press attention, though.)