can consider space a medium ?

ZapperZ

You are not free to redefine a physics description any way you like. You asked a question, it was answered.

Zz.

jetwaterluffy

Actually, for really loud sounds such as the death star exploding aalderen I can't see why they shouldn't make a noise in space. Space isn't a perfect vacuum, after all, and when you have 10^38J or 10^32J whatever, even a small fraction of that is going to make a gigantic noise that even micropascals pressure might let through.

ZapperZ

First of all, let's not get this thread off track.

Secondly, there is no "sound" here because "sound" requires a vibration of a medium. When one is no longer in the "viscous flow" regime, there is no longer a correlated motion of the medium. You may have a shower of particle, etc. moving, but this is not what you call "sound".

So be VERY careful in the terminology that you are using. Like I said, none of us here are free to redefine many of these terms.

Zz.

Hetware

I've never seen a virtual particle, have you? AFAIK, a virtual particle is a mathematical construct. Quantum field theory must have some merit or it wouldn't have its predictive power, but there are some serious problems with QM when it the mathematical assumptions are taken as representing physical reality.

Chronos

I tend to think of virtual particles as being like zeros used as placeholders in numbers. They represent a disturbance in a field, but, have no independent, objective reality.

Hetware

What do you mean by "field"? Is this an algebraic field? A vector field in the sense the physicist invented? Is this a vector field in the sense the mathematician absconded with? Is this a potential field? Wheat field? ...

Hetware

What's the difference between the content of an empty box in deep space, and the content of a box of zero volume anywhere?

JustinRyan

One box has real volume and can have real contents....the other doesn't have any volume so cannot contain anything real.

No-one has ever seen a quark either. Are they real?

Chronos

For discussion, see http://science.jrank.org/pages/7195/...Particles.html, and http://math.ucr.edu/home/baez/physic...particles.html

harrylin

You may like the following (some people hate it):
https://en.wikisource.org/wiki/Ether..._of_Relativity

ZapperZ

And some people hate it with good reason (it is outdated!), and you should know well enough to not use it because it will only add unnecessary confusion to this!

What's next? Reference to the Caloric each time we have a discussion on Thermodynamics?

Zz.

TurtleMeister

The light from very distant objects is red shifted because they are moving "expanding" away from us at great velocity. I have read that this limits how far away an object can be for us to view it (observable universe). I have also read that this may not be a limit to the size of the universe because space itself can expand faster than c. Does this imply that space is a medium and that the speed of light limit only applies to things that are in it?

Hetware

Suppose the empty box is in free float near a strong gravitational attractor. The volume contained therein will have some amount of curvature. That is to say, a non-zero stress-energy tensor. That is to say, the box will contain momenergy.

Now, you couldn't simply take a whole bunch of boxes, pack up all of the space-time curvature and ship it off via intergalactic FedEx. You can't confine that form of momenergy in a material container.

In addition, no box will ever be completely devoid of content. If nothing else, there will be background radiation in it. If it is ever accelerated, that will stir up small EM disturbances.

Even the material of the walls of the box will have some mass, that will equate to the presence of a miniscule space-time curvature.

harrylin

Outdated means in physics disproved; physics is not fashion. I am not aware that the GR field concept was disproved.

Hetware

Outdated? How so? Because people don't pay it no never mind these days?