Through which medium does light travel.

[alt_f13]

Sound travels through matter. Water waves etc. travel on a plain.

 

But how does EM radiation travel? What are the waves generated on? Are they distortions in spacetime itself?

[bh_doc]

Light travels through aether, of course!

[alt_f13]

Of course; how could I have missed it?

[YT2095]

the last I remember Aether was still considered a hypothetical medium, and not actualy a Fact.

 

em waves (photons) are their own medium as they are a distinct entity just like a spaceship or a fingernail, it doesn`t need a medium, it just IS

[J'Dona]

Myabe I'm thinking of a different aether, but I thought that the eather through which light was thought to travel was shown not to exist around the year 1900. Everyone thought that it did exist and these two guys set up an experiment to show that it did. The results were negative... I'll have to check who they were some time.

 

Or has there been new evidence to show that it might exist?

[Sayonara]

Whenever we find some previously unknown quality of space, the aether hordes say "yeah, that's aether. Told you!"

[swansont]

Myabe I'm thinking of a different aether' date=' but I thought that the eather through which light was thought to travel was shown not to exist around the year 1900. Everyone thought that it did exist and these two guys set up an experiment to show that it did. The results were negative... I'll have to check who they were some time.

 

Or has there been new evidence to show that it might exist?[/quote']

 

Michelson and Morley showed we were not moving with respect to the ether. The observation of stellar aberration had already established we could not be stationary with repect to it.

 

But, as Sayonara said, people use the term "ether" for new discoveries, adding further confusion - like relativity isn't confusing enough to the average person in the street.

[alt_f13]

yah. I'm pretty sure we were all joking about teh etehr.

 

[edit]

 

I'm still not clear on how em can be a wave of itself... I mean, if light was a wave OF photons, sure... but a wave OR photons? Every other wave has a medium by which it travels.

[Sayonara]

Also it's annoying as aether should be pronounced as either "aye-ther" or "A-ther".

[NSX]

I'm still not clear on how em can be a wave of itself... I mean, if light was a wave OF photons, sure... but a wave OR photons? Every other wave has a medium by which it travels.

 

Well, we can behave like waves too.

[alt_f13]

Uhuh.. but then our bodies would be the medium for the wave.

[John]

Depending on the experiment, light acts as either a wave or a stream of particles. In other words, it exhibits properties of both. Light is a strange thing. It requires no medium to travel, so far as I know.

[alt_f13]

How is that possible, though? Particles use 3d space as a medium for travel. Sound waves are fluctuations in local air density and water waves are moving crests on a flat surface.

 

The only conclusion I can come to is that EMR is the distortion of 3D space itself.

[John]

Read this. It might prove informative: http://www.olympusmicro.com/primer/lightandcolor/particleorwave.html

[YT2095]

we can fire a bullet in space in the near perfect vacuum, it will still travel without any supporting medium, in fact it`ll travel alot better out there than it does down here in fresh air.

 

same applies to photons

[Sayonara]

If EMR is a distortion in space, photons fired at each other ought to undergo some kind of deflection.

 

Iirc this has been tested but I can't for the life of me remember the details.

[alt_f13]

Read this. It might prove informative: [url']http://www.olympusmicro.com/primer/lightandcolor/particleorwave.html[/url]

 

 

Yah, I get that. But...

 

Light has frequencies, therefor something is vibrating or moving with varying densities. What is vibrating? There could be waves of photons at different frequencies; that makes sense to me. If photons were stationary, the wave could move via them. It would be the same thing, but without particle translation.

[John]

Light is unique. It shows properties of being both a wave and a particle, so perhaps attempting to deduce its means of travel using the rules for either is the wrong approach.

[Martin]

Sound travels through matter. Water waves etc. travel on a plain.

 

But how does EM radiation travel? What are the waves generated on? Are they distortions in spacetime itself?

 

the theory of gravity (GR) that's been in use since 1915 predicts

gravity waves and there is a detector that just went in to operation looking for them

those would be slight temporary distortions in the geometry of spacetime, I picture them as ripples, that spread out from some source like a collapsing star or a near-collision of two very dense stars

 

but this is not EM!

 

EM waves are temporary disturbances in the electric field (or electric and magnetic fields treated as a single entity

 

you are asked first to imagine a static electric field extending outwards from some charged object, the forcefield of that charged object extending out thru all space

 

and then you are told some equations by which that field can superimposed with all the other similar fields of all the other charges, to make one electric field extending thru out the U

and then you are given some rules (maxwell eqn) by which that field can be twanged and will continue vibrating, with the energy spreading out forever

 

so that, in imagination, the field is almost a real thing, like a pondsurface or a drumhead or somesuch 3D medium of vibration

 

but then again it isnt and that was just the classical picture, not the quantum field picture------and physics never answers any basic question, it is just a sequence of improvements in what one imagines.

 

its all in the imagination and the amazing thing is how well it works

[alt_f13]

 

you are asked first to imagine a static electric field extending outwards from some charged object' date=' the forcefield of that charged object extending out thru all space

 

[/quote']

 

That is what I needed. That is the medium by which light travels. Just a regular old EM field.

 

I bet photons have their own EM fields, but the strength of the EM field coming from a photon is so intense, its registration seems equally or more important than the physical entity itself, in the eyes of scientists. A photons interaction with other photons is probably greatly affected by the fields they produce, giving them the appearence of waves themselves, like magnetically charged ball bearings.

 

 

Or light could just be the 3rd state of energy, so to speak. Like liquid having properties of both gas and solid state matter and being the transition between the two (in most cases), there is probably just more possible states of energy than we realize today.

[kjitta]

EM radiation, photons, do not need a medium to propagate through, or any other means of transmission. You cannot compare EM radiation to mechanical waves. 3D space, as you metnioned earlier is not a medium as such and thinking of it as the medium for particles to propagate in is inaccurate and misleading. Mechanical waves need a medium because they are indeed manifested as compression and relaxation of matter. This same analogy does not hold for EM radiation.

"I bet photons have their own EM fields, but the strength of the EM field coming from a photon is so intense, its registration seems equally or more important than the physical entity itself, in the eyes of scientists."

The EM field is to fast to detect, and radiation is detected in the form of absorption of photons (photo electric effect). The EM field does not originate from photons as with a charged particle where the electric field is infinite at an ideal point charge.

I prefere to think of EM radiation as a stream of photons whos statistical behavoir assimilate wave properties.

[YT2095]

I prefere to think of EM radiation as a stream of photons whos statistical behavoir assimilate wave properties.

Ditto

[alt_f13]

I would, except when people describe light as exhibiting "wave like properties", which suggests to me that light is a function of something other than particles.

 

If light is made of particles.. then it is made of particles, but then why describe it as something other than photons moving in wave like patterns? Why describe light as a wave?

[Aeschylus]

I would' date=' except when people describe light as exhibiting "wave like properties", which suggests to me that light is a function of something other than particles.

 

If light is made of particles.. then it is made of particles, but then why describe it as something other than photons moving in wave like patterns? Why describe light as a [i']wave[/i]?

 

Personally I think if your going to think of light as anything, then think of it as waves, with the possible exception of high frequency em radiation which exhibits particle-like behaviour that's not difficult to observe.

 

Of course for a fuller descripion you need to look at quantum mechanics, which shows that neither a classical particle nor a classical wave description of light is completely adequate.

[Dave]

If light is made of particles.. then it is made of particles, but then why describe it as something other than photons moving in wave like patterns? Why describe light as a wave[/i']?

 

Because things like Compton Scattering and electron diffraction occur, that can only be explained by a wave-like description.