1) What part of "we can directly image the Lorentz contraction" are you having trouble with? 2) I gave you another link which you can access.
The part where you claim length contraction is observed. "We observe the contraction of the collision region with increasing vortex velocity". I understand that the collision region gets smaller with increased velocities of opposite moving vortices. It is assumed in this paper that this is because of length contraction. Which goes back to what I said - length contraction is assumed for the explaination (as far as I can tell from reading the abstract). I suspect that you've only read the abstract as well. The second link just takes me back to the first link - did you even try it?
I think I didn't. It took me here and asked for a username password. Perhaps your computer has this information saved and took you directly to the article?
You're probably right. I retried it, and it didn't work. Mea culpa. Anyhow, if at all possible, I suggest you seek out the article, possibly at a technical library. If it's convincing enough to get into Phys.Rev.Letters it carries significant weight.
I don't doubt that any of the information contained within the article is wrong. But like I said, I don't know that this is proof of length contraction or intended to even be such. As far as I can tell, it offers an explaination for the smaller collision region according to special relativity.
But wait. It says they directly image the shortened collision region. What more do you want? The measurement of the decay times of particles in accelerators is an observation of time dilation. Why is that good enough, but an image of a collision area contracting in agreement with the Lorentz equations is not? Me confused. Very cornfused.
Do you know the intrinsic nature of high speed vortex collisions? This isn't your simple inelastic collision model, it is a 3D model of vortices. I don't claim to know all the details, but there is one thing I can gather from the abstract. And that is length contraction is used as an explaination of observing smaller collision regions, but length contraction of any objects is not observed directly. Decay times in particle acceleraters is not as complex. You are dealing with 1D motion and the particles decay at a slower rate (i.e. time dilation). I am not trying to be stubborn here, really I am not Please Register or Log in to view the hidden image!
I know nothing about high speed vortex collisions. Thank god! Please Register or Log in to view the hidden image!
You seemed to inadvertantly missed one crucial word in the presentation: "Assuming". They make an assumption and based on that assumption then claim they can see the contraction. They do not claim that assumption is reality otherwise they would say they "Saw" length contraction.
MacM, if you had read the paper, you would know that they do claim to have a direct image of Lorentz contraction. In fact, it's in the very first paragraph of the paper, which is a discussion of previous experiments involving length contraction. Like all good physicists, since that imaging does have an underlying assumption (which appears reasonable enough to me, but I don't know enough to say), they mention this in the abstract. Of course, in the paper there's a discussion of why this is reasonable, and apparently PRL's reviewers of this paper thought likewise (and they most certainly are knowledgable). Now, do you have an actual objection to the assumption? Or are you just arguing semantics, and not physics, like you're so keen of saying? In fact, unless anyone can come up with a reasonable physics explanation of why this assumption doesn't hold, I'll claim this paper as proof of length contraction in the future.
funkstar, I'd first like to see you explain the intrinsic nature of 3D vortices Please Register or Log in to view the hidden image!
I do object. An assumption is still an assumption and the results are totally contentgent on such assumption. In consideration that others have already advanced alternative views which they claim there is no actual contraction but that there is a form of Penrose-Terrel Rotation. http://www.hypervisualization.com/collision/spheres.htm http://www.anu.edu.au/Physics/Searle/paper2.html http://www2.corepower.com:8080/~relfaq/penrose.html
Why should I? In one corner we have Phys. Rev. Letters, bastion of physics, in the other corner we have Aer, random forum poster. You'll excuse me if that doesn't appear much of a match, IMO. Now, you say length contraction has never been observed. This paper puts that to the lie. If you can't explain why this paper doesn't show length contraction, it's only reasonable to default to what PRL claims, i.e. that it does. So, is that a "no, I don't have any actual objections"?
Perhaps they are unaware of the more modern view where there is no actual contraction but only rotation. http://www.hypervisualization.com/collision/spheres.htm http://www.anu.edu.au/Physics/Searle/paper2.html http://www2.corepower.com:8080/~relfaq/penrose.html You really should settle down and stop being so cock sure of yourself.
Which others, and what alternative views? And the relevance of this to the imaging used in the paper?
The abstract didn't even claim that length contraction was observed! For you to make such a claim is not honest.
You are aware that Penrose-Terrell rotation is the result of factoring in light propagation delays in observations of (that's right) length contracted objects? Your third link even explains it nicely... Please Register or Log in to view the hidden image! Being told this by a man who implicitly claims that most every part modern physics, from cosmology to physical chemistry to high-energy physics to quantum mechanics is wrong, based on a simple misconception he has about str - that has to be the single most obvious instance of the pot calling the kettle black I have ever seen. Goodnight, gentlemen. Intellectual tennis will resume, but, for now, I retire to sleep, perchance to dream.
Like I said, the area of the 3D vortex collision was said to be smaller. Vortices are fluid entities and as such many things dictate how they behave, especially when you are talking about collisions. It's not as simple as funkstar would have you believe.
