EM waves can travel through space!

[Zarnaxus]

soo, why exactly can electromagnetic waves travel through space? or do we now know? They are a wave, so they must "wave" through something.

 

I have asked my science teachers this. They say that an electric field is generated, which in turn generates a magnetic field, which creates an electric field, etc. But is this a legitimate explaination?

 

Is it that light is made of photons, which are like a particle, so they can travel through a vacuuuum?

Is it that the wave is actually "waving" through fluctuations in space at a quantum level (virtual particles)?

 

I am confused. To me, radiation should not be reaching earth from the sun. It has no medium. If it doesn't need a medium, why?! How?! I want to leearn!!

[steevey]

soo, why exactly can electromagnetic waves travel through space? or do we now know? They are a wave, so they must "wave" through something.

 

I have asked my science teachers this. They say that an electric field is generated, which in turn generates a magnetic field, which creates an electric field, etc. But is this a legitimate explaination?

 

Is it that light is made of photons, which are like a particle, so they can travel through a vacuuuum?

Is it that the wave is actually "waving" through fluctuations in space at a quantum level (virtual particles)?

 

I am confused. To me, radiation should not be reaching earth from the sun. It has no medium. If it doesn't need a medium, why?! How?! I want to leearn!!

 

Well, they aren't just "waves" that travel though things, photons are also particles which are ALSO waves. The the answer is they are waves of existence itself.

 

On top of that, but it's also more or less one of Newton's laws of motion since nothing is stopping the photon from traveling in a straight line through the vacuum of space (usually), although light just never stops really even being light anyway unless its sucked into a black hole or stored in a chemical bond.

[Cap'n Refsmmat]

The medium is the electric and magnetic fields. Electromagnetic waves are fluctuations in those fields. They're also particles called photons, simultaneously. This may help:

 

http://en.wikipedia.org/wiki/Wave-particle_duality

[A Tripolation]

The following is a concept that is based on Maxwell's Equations, most notably, Faraday's Law, and Ampere's Law.

 

Say you have a changing electric field. You will generate a magnetic field. Let's say that this electric field oscillates, going back and forth from positive to negative. That oscillation will generate a magnetic field. Because the electric field's rate of change has to change in order to allow it to oscillate back and forth, the magnetic field will not be constant and it will change over time. Then, Faraday's law states that a changing magnetic field (which is what we have so far) induces an electrical field.

 

So, the changing magnetic field creates a changing electric field. The electric field generates a changing magnetic field. And the process starts all over again.

 

Electromagnetic radiation, of which light is an example of, is electric and magnetic fields, self-propagating through space. It can be seen as a car that runs off if it's own exhaust. Self-powered, and no need for a medium or aether.

 

Hope this makes sense.

Edited February 8, 2011 by A Tripolation

[lemur]

I have asked my science teachers this. They say that an electric field is generated, which in turn generates a magnetic field, which creates an electric field, etc. But is this a legitimate explaination?

I don't think that either a magnetic field or electric fields require a medium, so if you accept that light is composed of these two types of fields propagating at the speed of light, you should be able to accept that light can travel through a vacuum as only the propagation of force-fields. Is your question whether there is direct evidence of the electric and magnetic fields in a light wave?

[alpha2cen]

Light can be created without electric or magnetic field. All objects emit waves, whose wave length is depend on temperature.

From high temperature to low temperature the wave energy is moved.

[steevey]

Light can be created without electric or magnetic field. All objects emit waves, whose wave length is depend on temperature.

From high temperature to low temperature the wave energy is moved.

 

Well, its known that only charged particles or interactions with charged particles Emmit light (as far as I know), and they can also be caused by quantum jumps, or where electrons go down to a lower energy state.

[lemur]

Light can be created without electric or magnetic field. All objects emit waves, whose wave length is depend on temperature.

From high temperature to low temperature the wave energy is moved.

 

 

Well, its known that only charged particles or interactions with charged particles Emmit light (as far as I know), and they can also be caused by quantum jumps, or where electrons go down to a lower energy state.

I was also under the impression that electron motion is always responsible for black-body emissions, even at increasingly lower temperatures. I had the idea that it was just a question of energy-level probability in a bell-curve. I.e. even if the vast majority of electrons in a substance are cold (i.e. at their lowest and most stable state), there might still be a small minority that have still retained a higher energy-level, which could drop and emit a photon. I always have to warn that I could be wrong though, because as hard as I try to learn this stuff, there's always some gap for me between the explanation I read and my intuitive understanding, which makes me prone to making mistakes when relaying what I have learned to others, I think.

Edited February 10, 2011 by lemur

[steevey]

I was also under the impression that electron motion is always responsible for black-body emissions, even at increasingly lower temperatures. I had the idea that it was just a question of energy-level probability in a bell-curve. I.e. even if the vast majority of electrons in a substance are cold (i.e. at their lowest and most stable state), there might still be a small minority that have still retained a higher energy-level, which could drop and emit a photon. I always have to warn that I could be wrong though, because as hard as I try to learn this stuff, there's always some gap for me between the explanation I read and my intuitive understanding, which makes me prone to making mistakes when relaying what I have learned to others, I think.

 

 

Well black bodies, at least on Earth still emit light, just in a different spectrum which we can't see, usually infra-red. The light coming from black bodies is usually just low in energy (or infra-red) unless its heated up.

Edited February 10, 2011 by steevey

[lemur]

Well black bodies, at least on Earth still emit light, just in a different spectrum which we can't see, usually infra-red. The light coming from black bodies is usually just low in energy (or infra-red) unless its heated up.

Right, but even if you had a piece of iron at 1K in deep-space, wouldn't it emit SOME amount of radiation, although it would be ultra-low frequency and presumably very intermittent for various atoms?

[steevey]

Right, but even if you had a piece of iron at 1K in deep-space, wouldn't it emit SOME amount of radiation, although it would be ultra-low frequency and presumably very intermittent for various atoms?

 

Hmm, unless its being accelerated, I don't think so. But I guess, there may be some very small effect from the cosmic background radiation and larger effects from cosmic rays. But if nothing about the iron changes as its speed or energy level or the electron configuration, there's no reason to emit light as far as I know. Otherwise it would just emit all of its energy, but thats not possible for any matter to have 0 energy unless its no longer matter.

Edited February 10, 2011 by steevey

[swansont]

!

Moderator Note

Further discussion on atoms near 0K has been moved to http://www.scienceforums.net/topic/54745-behavior-of-systems-near-absolute-zero/