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I hate to put a damper on the enthusiasm about this awesome topic, but this article doesn't even contain a hint of any reason to believe that the NASA scientist

by Steuard 13y ago

I hate to put a damper on the enthusiasm about this awesome topic, but this article doesn't even contain a hint of any reason to believe that the NASA scientist in question is making progress on any sort of FTL technology. Alcubierre's work on "warp bubbles" has been known for years, but as even this article points out, there are enormous roadblocks to making it practical. For example, it requires matter with properties that have never been observed in the universe (namely, violations of the positive energy condition). If this NASA scientist thinks that he has a way to produce such matter, that would already be a bigger deal than any scientific finding in (conservatively) the past thirty years. Why hasn't he announced that? Also, Alcubierre himself is quoted in the article pointing out that no signal from inside the warp bubble can ever reach the front of the bubble to "turn it on" in the first place. (As I recall, Alcubierre's equations describe an "eternal" warp bubble, moving forever with no beginning or end.) Has the NASA team found a way around that? The article doesn't give any hint that they have. (Nor that they haven't, but as a theoretical physicist myself I'd like to think that I'd have heard of a breakthrough like that.) So what I want to know is, first, why did the NY Times decide this was worth reporting on (while leaving out any evidence that this NASA team is capable of making meaningful progress)? And second, why is NASA devoting multiple salary lines to this particular project? (There might be good answers, but they aren't evident here.)

kamaal 13y ago
>>For example, it requires matter with properties that have never been observed in the universe (namely, violations of the positive energy condition). At first I thought about this, but then its for us to really ponder on a simple fact. You can achieve a X goal by doing Y, but to say you can achieve only by doing Y is wrong. Scientific history is standing testimony to that. People have expressed skepticism about anything and everything, stuff like airplanes, nuclear energy, mobile phones, internet anything you name it. 50 years before they were all invented and put to use, they would have all seemed pointless directions of pursuit- yet all of it makes perfect sense today. Yet some tangential line of thinking causes a major technology break through every now and then we are left wondering what we where thinking all along.
- 2muchcoffeeman 13y ago
  Remember that the people who make these discoveries are scientists. It's one thing for a person on the street to be skeptical it's another thing when a scientist in the field in question is skeptical. Now these guys don't even have a hypothesis on how to turn the machine on. Forget the engineering. They can't get an idea to work. I'm with the GP, this is not very exciting. Even having a working idea on how all the parts may work would be more exciting than this article.
  - kamaal 13y ago
    >> It's one thing for a person on the street to be skeptical it's another thing when a scientist in the field in question is skeptical. No, Scientists are human beings too. And the fact is, a scientist's thoughts are biased based on what the person knows. People co relate the events to happen in future on the basis of what they know right now. Which is the root cause of all problems. Though sometimes skepticism is perfectly valid. >>Now these guys don't even have a hypothesis on how to turn the machine on. These guys are not working on building the machine. >>Forget the engineering. Exactly. The first rockets were not built by directly opening up the lab and making the prototype in the first hour. Even while building things like the first rocket, or the first viable airplane a lot of math and physics work had to be done. Which is what is happening now. >>They can't get an idea to work. Seems like they already have experimental test bed to verify their math. >>I'm with the GP, this is not very exciting. Even having a working idea on how all the parts I'm excited. Its not like software where you fire up your IDE and just get down to coding. That works with software because 100% of whatever we do is already done and proven by nearly everybody else. We just exercise the same to our domains of business. Building some thing like a warp-drive may very well require some years of work on math and physics before any field trials are started. Basically nobody has done anything like this every before. No one knows the consequences, or the side effects or even the kind of effort such an endeavor would demand. If you want an easy analogy, Alonzo Church died finishing his work on the lambda calculus before he could see a working electronic computer. Same could be told about Alan Turing. Yet these guys had mathematically demonstrated all they said was possible. When the first gates were built, people expressed the same skepticism if the combination of these AND-OR-XOR gate will ever achieve something substantial. Or when the first brick was built, and when the first wheel was built.
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
Here's a nice blog post by a scientist giving a bit more quantitative discussion of why this proposal doesn't seem plausible: http://excursionset.com/blog/2013/7/23/dump-the-warp-core http://excursionset.com/blog/2013/7/23/dump-the-warp-core

by Steuard 13y ago

kamaal 13y ago

>>For example, it requires matter with properties that have never been observed in the universe (namely, violations of the positive energy condition). At first I thought about this, but then its for us to really ponder on a simple fact. You can achieve a X goal by doing Y, but to say you can achieve only by doing Y is wrong. Scientific history is standing testimony to that. People have expressed skepticism about anything and everything, stuff like airplanes, nuclear energy, mobile phones, internet anything you name it. 50 years before they were all invented and put to use, they would have all seemed pointless directions of pursuit- yet all of it makes perfect sense today. Yet some tangential line of thinking causes a major technology break through every now and then we are left wondering what we where thinking all along.

2muchcoffeeman 13y ago
Remember that the people who make these discoveries are scientists. It's one thing for a person on the street to be skeptical it's another thing when a scientist in the field in question is skeptical. Now these guys don't even have a hypothesis on how to turn the machine on. Forget the engineering. They can't get an idea to work. I'm with the GP, this is not very exciting. Even having a working idea on how all the parts may work would be more exciting than this article.
- kamaal 13y ago
  >> It's one thing for a person on the street to be skeptical it's another thing when a scientist in the field in question is skeptical. No, Scientists are human beings too. And the fact is, a scientist's thoughts are biased based on what the person knows. People co relate the events to happen in future on the basis of what they know right now. Which is the root cause of all problems. Though sometimes skepticism is perfectly valid. >>Now these guys don't even have a hypothesis on how to turn the machine on. These guys are not working on building the machine. >>Forget the engineering. Exactly. The first rockets were not built by directly opening up the lab and making the prototype in the first hour. Even while building things like the first rocket, or the first viable airplane a lot of math and physics work had to be done. Which is what is happening now. >>They can't get an idea to work. Seems like they already have experimental test bed to verify their math. >>I'm with the GP, this is not very exciting. Even having a working idea on how all the parts I'm excited. Its not like software where you fire up your IDE and just get down to coding. That works with software because 100% of whatever we do is already done and proven by nearly everybody else. We just exercise the same to our domains of business. Building some thing like a warp-drive may very well require some years of work on math and physics before any field trials are started. Basically nobody has done anything like this every before. No one knows the consequences, or the side effects or even the kind of effort such an endeavor would demand. If you want an easy analogy, Alonzo Church died finishing his work on the lambda calculus before he could see a working electronic computer. Same could be told about Alan Turing. Yet these guys had mathematically demonstrated all they said was possible. When the first gates were built, people expressed the same skepticism if the combination of these AND-OR-XOR gate will ever achieve something substantial. Or when the first brick was built, and when the first wheel was built.

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

Here's a nice blog post by a scientist giving a bit more quantitative discussion of why this proposal doesn't seem plausible: http://excursionset.com/blog/2013/7/23/dump-the-warp-core http://excursionset.com/blog/2013/7/23/dump-the-warp-core