Re: Speed limit at C a misconception?

Timo Nieminen <timo@xxxxxxxxxxxxxxxxx> wrote in
Pine.LNX.4.50.0508231305470.4515-100000@localhost:">news:Pine.LNX.4.50.0508231305470.4515-100000@localhost:

> On Tue, 23 Aug 2005, Skywise wrote:
>
>> Timo Nieminen <timo@xxxxxxxxxxxxxxxxx> wrote:
>> > On Tue, 23 Aug 2005, Skywise wrote:
>> >
>> >> My understanding of the phrase "nothing can go faster than light"
>> >> applies to material objects, ie spaceships, baseballs, and protons.
>> >>
>> >> If that is correct, then the phrase "nothing can go faster than
>> >> light is a popular misconception" is false.
>> >>
>> >> Right?
>> >
>> > The "misconception" part was the inclusion of nonmaterial objects
>> > (but see below) in the "nothing" above. The point being the reaction
>> > that FTL phase or group speeds elicit: "SR is falsified!" or "Isn't
>> > that prohibited by SR?"
>> >
>> > A complication exists, however, since one might not wish to call
>> > information, energy, momentum, and angular momentum "material
>> > objects". The word "thing" is such a nicely imprecise term!
>> >
>> > Just from responses I've seen from others, not all people share your
>> > understanding of the phrase above.
>>
>> I think the only quesiton I have left is, "is my understanding
>> correct"?
>
> Pretty much. But you need to include the energy, momentum, angular
> momentum, and information carried by fields as well as "material
> objects".
>
> Also, the theory says nothing that forbids tachyons.
>
> If you consider photons to be "material objects", then, sure, your
> understanding looks to be correct.
>
> Fundamentally, when you get down to quantum field theory, then the
> momentum, energy etc commonly considered to be carried by "physical
> objects" is also carried by fields. So whether you think of things in
> terms of particles or fields is somewhat optional.

Ah yes! The 'wavicle' problem. And, probability amplitudes. I've
read a few books that address the topic for the layman (ie the
mathematically challenged, ME!).

Yeah, I guess at the quantum level there is a non zero probability
of something exceeding the speed of light, but we're talking about
single particles/waves. When we start talking about macroscopic
objects - baseballs and spaceships - and we start adding up all
the probablity amplitudes, the probability of that macro-object
exceeding c becomes exceeding close to zero.

I guess my real concern was that people who don't know any
better are going to read the news story and read this statement
about this 'popular misconception' and get the wrong idea.

Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism

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