electro magnetic radiation is a wave apparently, but it travels fastest in a vacuum! how can a wave exist in a vacuum with nothing to act as a enegy carrer! to me this seems to be a inposabilaty. theory i have is there must be a electromagnetic filed everywhere witch carrys the radiation, possibly in a different dimension.

any physicists here to aner this question, from what i understand now one truly knows what electromagnetic radiation is

There is something to act as an energy carry-- the photon which contains the quantized packet of energy that is a burst of electromagnetic radiation. The photon simply isn't hitting into anything else. Typically, what happens is a photon will hit into something, it's energy will be absorbed and then readmitted as another photon. When nothing is around, there are no collisions and no reemittances, just the initial photon moving in some direction.

I don't know what you mean when you say electromagnetic radiation, impossible. Do you mean that light and radio waves are not made up of electromagnetic radiation. Or are you referring to the fact that you think that light waves cannot travel without a medium. If it is the latter, it was once believed that there is a medium called ether that permeated space and it was the medium that light traveled through. The famous Michelson-Morley (not sure I spelled the names right) was unable to detect the ether, Einstein said the the ether is a fiction. It may be that since light has a dual nature, it is both particle and wave, that the dual nature allows it to travel without a medium. Sound does not have a dual nature and needs a medium.

dace

if it is transmitid with photons then it would be a particle and not a wave

how can somthing be a particle and a wave?

We don't know. Thousands of experiments have been run on it. And it is always one or the other. Never does it show up as both in any experiment. But it gets worse, They have discovered that particles have a dual nature. They call it matter waves. It is the dual nature of particles (sub atomic) that allows some of the crazy things that happen in quantum mechanics.

dace

dont know about that. there isant mutch detail recwired in as phisics. so i only know the basics. ive only just lernet about quarks

The Particle-Wave duality of light is very well known and documented. Yes, the Michelson-Morley experiment using an interferometer confirms, without a doubt, that the speed of light is constant despite whatever material, or lack thereof, exists along a path. That's because light travels the absolute smallest possible distance at the absolute smallest possible unit of time. It's hard to explain if you don't have a solid knowledge of calculus, and even then it's no easy task, but think about it this way. If you slice a unit of time to an infinitesimally, but real, small unit of time (continually slice time in half an infinite amount of times), then you come to a "quantized" amount of time. That's the amount of time it takes light to travel from a quantized amount of distance. Nothing can exceed this speed because time can't get smaller than infinitely small (approximately 0). This is essentially part of the explanation as to why nothing can travel faster than light (relativity is another issue... as you go faster you actually get heavier and so it becomes infinitely difficult to apply an acceleration force-- it basically begins to require infinite force due to an approaching infinite mass to move matter at light speed... but I digress).

That's speed and why it requires no medium (btw, all mediums respond essentially the same to light-- it's hit by a photon which causes the admitting of another photon-- if something else gained momentum from the photon, like an electron excitation, then the photon that's emitted is of a different wavelength, etc etc). The only thing is that if a photon travels without hitting anything it never stops. There is a momentum associated with photons and the effects of friction, etc., are negligible due to the incredible speed associated with photons. They don't need a medium through which they propagate because photons are, in many ways, particles with an associated momentum (though no associated mass). This, in fact, is part of the evidence for photons being particles, as well as our ability to detect single photons since they always are detected in definite packets of energy. These quanta (quantitative packets of energy) are defined as the amount of energy from E/M radiation divided by some integer which always ends up being the same number. This is how much energy a single photon carries.

Evidence of the wave like nature comes from interference patterns detected through "split" experiments, as well as explaining the ability of certain wavelengths to be seen/absorbed/pass through, etc, and also can very accurately determine the energy of such waves. It also explains the radial spread of E/M energy.

E/M radiation is actually made up of an electrical energy wave and an orthogonal magnetic energy wave traveling in phase with each other...

You don't sound much like a scientist, and have terrible spelling. I hope these are indicators of your lack of age. how old are you?

quantum mechanics is very difficult to understand for anyone. I highly recommend you get this book. In Search of Schrödinger's Cat: Quantum Physics and Reality (Paperback)

Amazon.com: In Search of Schrödinger's Cat: Quantum Physics and Reality: Books: John Gribbin

It is a great book to get you interested in quantum mechanics. You'll need to study the stuff in college to learn it in any more detail than that.

im 17 and dyslexic, i do use a spell checler, im dooming physics and cemestry A levels. i haven't seen a explanation for e/m radiation witch makes seance. how can a wave exist without a substance

Dear hessiess,

Is a B.A. in Physics close enough to a Scientist?

Picture a length of string in space. It is in a vacuum, but it is still free to vibrate back and forth. That allows it to have wavelike motion without the need for a medium to propogate in (just one example).

Light acts in a similar way. When passed through a pair of small slits, light divides into a difraction pattern (just another name for a rainbow), like ocean waves breaking around a rock. So light seems wave like.

In other experiments they behave as particles, just as a length of string, because it is of limited length. Example: when light hits atoms it can cause electrons to shift level, but only as a discrete event. The electron won't continue to shift out as more light comes in (in fact only a photon of exactly the right frequency can cause the shift).

And in string theory it gets weirder from there.

One last thing about light, it's velocity is not always constant. "c" the constant for the speed of light is defined as "The speed of light in a vacuum". Light slows down a wee bit in denser environments. In fact, I have heard of claims from researchers that they could virtually bring it to a stop. I'll believe it when I see it (or not see it since stationary light can't hit your eye ).

[Now here's a real brain teaser for you]

Einstien's Theory of Relativity states:

1. All motion is relative to the observer. She is always stationary from her own point of view.

2. There is no absolute frame of reference. Only messurements made from one observers perspective.

3. Even Physics professors will bedazzle students with tales of Twins, one who flies off to distant stars a high speeds for a few years while her sister remains behind. She returns only to find that her sister is long dead and world has completely changed after the passage of centuries.

Question: What is wrong with this picture?

Warning: thread necromancy in progress!

That's quite an unfair attack. This question:

is an astute observation, and if he's come up with it himself, it shows a good reasoning of what he's being taught in school.

Hessiess, here's a tutorial on wave-particle duality (that's the principle that states that something can act as both a wave and a particle [that's a greatly simplified explanation]) that I (well, Google actually) found on an A-level physics site:

S-Cool! - AS & A2 Level Physics Revision - Quicklearn

Have fun, and try to keep your interest in physics alive.

Welcome to Quantum mechanics!!

Or, we should think just as Feynman did:
It is neither.

A particle cannot have the properties of a wave, and a wave cannot have the properties of a particle. It must be neither, and we should only think of it as a "thing" which has those properties that we can observe and describe with QM.

Rather a lot i would say, the speed of the lightwaves is c/n with n the refractive index, and here are some: List of refractive indices - Wikipedia, the free encyclopedia
Light in silicium goes as slow as one-fourth speed of light!

I would also like to add that you do not really need quantum mechanics. From the electromechanical point of view the fields do contain energy, they are the medium. As such, the physical laws of the electrodynamics are Lorentz invariant; that is, they are still valid whatever your speed is.

In special relativity the transformation of positions is different then what we classically do, which is the Galilean transformation, not the Lorentz one! The mistake with the ether of at the beginning of the previous century and before was that people did not realize that the Lorentz transformation was to be used, and that the Galilean one is not consistent.

Ill leave the question for someone else

BTW eh not up to the wave-particle duality discussion, should follow a philosophy of QM course

Heres a thought. The E/M spectrum is the table of elements for particals and/or energy. Basically there and different types of matter, how do we know we aren't seeing different types of energy or particals? Yes there may not be any evidence to support this but its still an interesting thought.

Let me try to explain all this phenomenon.

About the wave thing. First of all the wave and an EM field are abstractions of certain effects. Now try to picture this. I have two charged particles.

The two dots

And they have fields of their own. When one of them oscillates up and down, it creates a so called distortion of its field and that distorted field affects the other particle. The oscillation energy of the first one is thus transmitted to the second one.

Physics is not interested in "WHY it affects the second one" it is interested in "HOW these two particles interact" the solution is an EM wave. You abstract (reduce) this effect to a wave (due to mathematical solutions).

At times when Quantum mechanics first emerged, it was obvious that physics actually observes the interaction of two physical systems. You cannot look at something and say that "it does this". You need to observe the effect via a subject and the deduced conclusion is the "how" of this effect.

The wave particle duality is a matter of observation.

Imagine that you are to observe me with closed eyes and to find where I am you throw me a giant rock. You will calculate my position from the "aaah" sound, but what you have calculated is my position before the rock hit me. After the event I am far off. Now photons, electrons are tiny objects. If you try to observe them you disturb them and you can only get a conclusion with an uncertainity.

The rate of this uncertainity determines if you will observe the subject as a particle or a wave. A high energy EM wave will cause a localized effect thus observable as a particle; whereas a low energy EM wave's effect will not be that localized, so you observe it as a wave.

It is nice to see a fellow physicist. But you are wrong on this. Speed of light is same everywhere. You observe it as if it is slowed because the effect is constantly absorbed by the particles in the dense matter. The light is constantly absorbed and re-emitted. This slight delay causes the change in the permeability and the permittivity (epsilon and mu)of the matter in question.

If one considers everything as observation one will not be puzzled about Quantum Mechanics and Relativity. Quantum Mechanics considers small objects as I have mentioned above which then comes up with the uncertainity principle and wave-particle duality.

In the case of special relativity. Stop thinking about Lorentz Transfomations and first consider this. A dead star far away is still observable from here as if it is there. It is because EM waves (light) has a limited speed. So for anything I observe, I cannot observe them instantly, there is a time delay for the effect (light) to reach me. And the faster my observable moves the bigger the effect. Lorentz Transformations correct this issue.

The problem with special relativity is that calculations are possible for only inertial referance frames (observables must move with constant speed and must never accelerate).

The problem with this picture is that, this picture assumes the return of one of the twins. Either it makes a circular trip or decelerates and accelerates in the opposite direction, it does accelerate. (for non physicists: Circular motion requires acceleration). Thus the relativistic calculation is not valid here. Thus not making this a paradox.

It is true that if one of the twins move with constant speed close to the speed of light away from the other twin. The moving twin will observe that the standing twin stays younger. But that is only what this twin OBSERVES. The image of the other twin takes time to reach the moving twin, just as the image of the moving twin takes time to reach the standing twin. hey both observe the other one younger, but neither is true. They both get old at the same rate, it is their observations that is deceiving.

These are actually very simple concepts when you know the underlying logic behind. I have seen many professors who will present them as magical, mysterious phenomenon; but that is not the case. As long as you know how to triangulate phenomenon, you see that it is all logical and even intuitive.

Just think about this:

When you do an experiment you are in the experiment too. The physical effects should reach you too, so you cannot exclude yourself or the detector you are using for the experiment. And inevitably the detector or you do get affected by the events to produce a result thus affecting the experiment itself.

After knowing this tell me which one is more intuitive. Quantum Mechanics which (simply put) accepts that when I throw a giant rock at somebody, I must affect the subject of the experiment. Or classical mechanics which considers that "when I do an experiment I observe the absolute event without even affecting the event a tiny bit"

So which one is more intuitive.

Tesla > einstein

So... you propose a luminiferous aether?

Ask Michelson and Morley what they think about a luminiferous aether.

One cannot compare Tesla to Einstein. One is an inventor, other is a physicist. Einstein is not a better inventor than Tesla, and Einsteins understanding of physics is superior to Telsas.

And there is absolutely no aether, everywhere is mostly empty, even the volume of a simple Hydrogen atom consists mostly of void (of course in the volume sense).