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Author Topic: Does "point mass" make sense?  (Read 3359 times)

Offline itisus

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Does "point mass" make sense?
« on: 06/03/2009 03:44:34 »
Somewhere on the WWW I read that the mass of some particle had been localized to some volume ridiculously smaller than the Planck volume.  How is it possible to determine a position so precisely while being certain the momentum (and mass) is even positive?  Heisenberg Uncertainty seems to prohibit it.


 

Offline Vern

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Does "point mass" make sense?
« Reply #1 on: 06/03/2009 05:10:07 »
I suspect this might be the same kind of volume measurement technique that was used at MIT to determine the size of the electron. The limit of their instrument was a certain small value; they measured nothing; they then assumed the size must be smaller than their small value limit.

I suspect that in the case of the electron measurement and probably in the one you cite here, they were trying to detect some imagined solid something, when in fact the thing was in reality a confined electromagnetic phenomenon. That last sentence is my own speculation. But it explains the null results.

I find that in software programming, it is usually an error to assign a value to a null result. In that case, null simply means that the value is unknown.



 

Offline lightarrow

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Does "point mass" make sense?
« Reply #2 on: 06/03/2009 12:41:29 »
Somewhere on the WWW I read that the mass of some particle had been localized to some volume ridiculously smaller than the Planck volume.  How is it possible to determine a position so precisely while being certain the momentum (and mass) is even positive?  Heisenberg Uncertainty seems to prohibit it.
Where did you read it?
 

Offline yor_on

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Does "point mass" make sense?
« Reply #3 on: 06/03/2009 13:21:24 »
Oh yes ::))

The link my man, the link...
 

Offline itisus

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Does "point mass" make sense?
« Reply #4 on: 20/03/2009 04:49:06 »
I could not find it again and now think I may have been wrong.  The number I remembered was 10^-80 cm, but that may have been 10^-80 cm^3 volume, much larger than Planck scale. :^(  It only bothered me later sice I was looking for something else.
 

Offline yor_on

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Does "point mass" make sense?
« Reply #5 on: 21/03/2009 21:48:31 »
So do the same search again please, one never knows :)
 

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Does "point mass" make sense?
« Reply #5 on: 21/03/2009 21:48:31 »

 

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