if a superliminal object did exist, would it appear as two identical objects to us

[rajama]

Not being familiar with astronomical objects, it took a while for me to realise that the artificial colour images referenced don’t really have any depth queues…

 

Also, it’s tempting to look at them like medical images, but these are not cross-sections of some extended object.

 

On comparing enough images, it’s fairly obvious they are rotating, and not necessarily around an axis that actually passes through their bulk...

 

Each seems like a trail of coloured dye wrapped around a whirlpool in a glass tank somewhere… they all appear to be spirals.

 

I have a few questions:

 

While I find the model really interesting, in relating it to these images why do nearly all of them have a ‘core’? Shouldn’t that part of the image be lost long before we see the blooms at either side?

 

Also, have you considered variations on your model to deal with SR?

 

What if a superluminal object passes through the interstellar medium, but only interacts (say) through gravity?

 

What if your ‘object’ was an intersection or merger of two ‘conventional’ objects, objects that remain fairly linear over astronomical distances - I’m guessing here, so maybe magnetic field lines?

 

Wouldn’t the superluminal model still apply?

[CPL.Luke]

rajama, look up planetary nebulae, these are supernovae remnants that have had their core completely obliterated.

[Mowgli]

On comparing enough images' date=' it’s fairly obvious they are rotating, and not necessarily around an axis that actually passes through their bulk...

Each seems like a trail of coloured dye wrapped around a whirlpool in a glass tank somewhere… they all appear to be spirals.

[/quote']

Yes, most of the DRAGNs look as though they are created out of superluminal galaxies moving along an arc.

While I find the model really interesting' date=' in relating it to these images why do nearly all of them have a ‘core’? Shouldn’t that part of the image be lost long before we see the blooms at either side?

[/quote']

I think of DRAGNs as galaxies (not stars) moving superluminally. All the stars in the galaxy will have a point like B', fairly close to each other. This is the core. Given that a galaxy can be hundreds of thousands of light years in extent, the core will remain for a while. In fact, a clear movement in the angular position of the core will be clear indication that my model is not valid.

Also' date=' have you considered variations on your model to deal with SR?

[/quote']

Well, starting with superluminality, it is pretty hard to reconcile the model with SR. You have any ideas?

What if a superluminal object passes through the interstellar medium' date=' but only interacts (say) through gravity?

[/quote']

This I don't know. I haven't considered energetics or gravity. Again, please post if you any ideas.

What if your ‘object’ was an intersection or merger of two ‘conventional’ objects' date=' objects that remain fairly linear over astronomical distances - I’m guessing here, so maybe magnetic field lines?

[/quote']

There was at least on DRAGN in the atlas I posted that seemed to have four arms. So it is a candidate for intersecting galaxies. There was a move to explain Cygnus A as two galaxies colliding (I think by Beade). But that explanation leaves out the remarkable symmetry between the lobes, the fact that all the "collisions" are almost head-on near the core region. Superluminality does explain these features.

[CPL.Luke]

I still don't see how its impossible to reconcile this with relativity, after all when were talking about objects very far away, its possible that there is some unknown mechanism that can work to make an object appear superluminal, but this mechanism can't occur in places where it would violate causality.

[rajama]

Well, starting with superluminality, it is pretty hard to reconcile the model with SR. You have any ideas?

 

 

If your object is moving fast enough the radial doppler shift tends to 1...?

[Mowgli]

If your object is moving fast enough the radial doppler shift tends to 1...?

If you did the calculation without pre-supposing SR (in other words' date=' as you would derive the Doppler shift for sound waves), you would get [math']k^2 = (v+1)/(v_o-1)[/math] where [math]v_o[/math] is the speed as seen by the observer. This has a limit of [math]v[/math] as [math]v\to\infty[/math].

 

I can send you the details as a pdf, if you are interested. In fact, the attached PDF has the calculations (in one of the appendices).

 

[ATTACH]1380[/ATTACH]

[Mowgli]

Glad to report that the paper describing this idea has been accepted for publication in IJMP-D.

Here is the journal ref:

International Journal of Modern Physics D, Vol. 16, No. 6 (2007) 983-1000.

Post-print version

URL: http://ejournals.wspc.com.sg/ijmpd/16/1606/S0218271807010559.html