[Geezer (OP)]

Goolag's "light-in-the-box" question provoked this question, but I thought it might be worthy of its own thread.

How much electromagnetic radiation (light, radio, etc.) can pass through a volume of space? Is there some theoretical limit at which spacetime "saturates" (for want of a better word), or is there no known limit?

[CliffordK]

Through space, I don't believe there is a limit.  The question might be whether a photon actually has both mass and volume, at which point there would be a theoretical limit in which all space is filled with photons.

In an atmosphere such as Earth's atmosphere, there is a limit of sorts.  Strong lasers tend to ionize the atmosphere and diffuse which is one of the reasons why energy beam weapons aren't very effective on Earth.

[JP]

Goolag's "light-in-the-box" question provoked this question, but I thought it might be worthy of its own thread.

How much electromagnetic radiation (light, radio, etc.) can pass through a volume of space? Is there some theoretical limit at which spacetime "saturates" (for want of a better word), or is there no known limit?

There are a couple of interesting things that should happen.  At some point, you begin to deviate from Maxwell's equations since light can interact with itself through weird quantum processes.  From what I understand, this happens at very high energy densities.  If you Google for phrases like "nonlinear light interaction in vacuum" you'll find a bunch of papers.  Just one example is here: http://prola.aps.org/abstract/PR/v129/i5/p2354_1

As for a more fundamental limit, there is certainly a limit at which our current theories break down.  I don't know exactly where that is, but it probably relates to the Planck density.  At that point, we don't know how to accurately predict the effects, which would involve quantum effects due to gravity interacting with the light.  

What I don't know is if you could somehow concentrate the light enough so that you form a black hole.  It's easy to think about stuffing enough mass into an area to form a black hole, since mass will play nicely and sit still until you get enough of it together.  Light has the unhappy tendency to go flying off at light speed as soon as you turn your back, so getting all your photons in the same place at the same time is going to be difficult.

[CliffordK]

Ok, Geezer.

I have a science experiment for you.

Head off to the star: R136a1

http://en.wikipedia.org/wiki/R136a1

Build a mirrored Dyson's sphere around it with the goal of focusing 8,700,000 "suns" into a single point.

Unfortunately, at 165,000 lightyears away, it will be a long trip to get there, and since the larger the star the quicker they die, unfortunately the star might go into supernova (hypernova) before we could ever even reach it.  Even so, if you could capture 100% of the light from the hypernova, all the better!!!

[CZARCAR]

assuming space is a vaccumn & the massless waves are saturated, I think u may have defined the LIFE FORCE?

[Phractality]

Contrary to mainstream science, I believe light propagates in the manner of an acoustic shear wave in an ultra-dense, ultra-stiff, ultra-strong aether. I believe the aether's density, stiffness and strength are finite, but far greater than any stress that we can impose on it experimentally. Even the most intense aether waves probably only wiggle the aether by a small fraction of a Planck length. However, given infinite space and time, it seems inevitable that shear waves from many directions will occasionally coincide at a point long enough to tear the fabric of the aether. When this happens, it might contribute to the expansion of space.

A logical connection between expansion of space and tearing the fabric of the aether can be inferred from my model in the New Theroies section.

[lightarrow]

Goolag's "light-in-the-box" question provoked this question, but I thought it might be worthy of its own thread.

How much electromagnetic radiation (light, radio, etc.) can pass through a volume of space? Is there some theoretical limit at which spacetime "saturates" (for want of a better word), or is there no known limit?

If the energy density is high enough, spacetime is warped so much that nothing can escape anymore (black hole). I leave the computations to you ...

[imatfaal]

LightArrow - take a look at my rough attempt in the Light in a Box Thread

http://www.thenakedscientists.com/forum/index.php?topic=39533.msg357146#msg357146

Seems too obvious and I am sure I have committed a huge howler

[lightarrow]

LightArrow - take a look at my rough attempt in the Light in a Box Thread

http://www.thenakedscientists.com/forum/index.php?topic=39533.msg357146#msg357146

Seems too obvious and I am sure I have committed a huge howler

For what I know, it's correct.
The secret in physics is to understand the basic concepts. Then you can do some computations. If they are approximate, it doesn't matter, you have time to refine them...

[goolag]

Excellent answers, giving me lots to think about!

I think I've invented a new interstellar bomb by the sounds of it - if ever we go to war with a nearby solar system we could fire these boxes off at the star - with the correct timings, the boxes would arrive at the target, having absorbed enough light to collapse in black holes with devasting effect.

I'm sure there'd be a more peaceful application though...

[Ken Hughes]

Ebergy = mass and so will dilate time just the same. If you put enough energy into a finite space, then that space will turn black. It will form a black hole.
The practicalities of this are debatable, since one would have to crush the Earth to the size of a grape to make it go black and that is with mass itself which is must more dense than radiation.
Other than that, I don't see any fundamental limit to the energy density applied.

[lightarrow]

I think I've invented a new interstellar bomb by the sounds of it - if ever we go to war with a nearby solar system we could fire these boxes off at the star - with the correct timings, the boxes would arrive at the target, having absorbed enough light to collapse in black holes with devasting effect.

If you have the possibility to do that, you surely can create a supernova as well...

[Geezer (OP)]

How close do fusion reactors come to hitting the limits?