Is it the meadiem Light waves effect?

[Whitedragon]

Main Question or Discussion Point

I heard about this from my teacher. What is it? Is it real? Is it the meadiem Light waves effect? Any help accepted.

 

[DrChinese]

I heard about this from my teacher. What is it? Is it real?

Welcome to PhysicsForums, Whitedragon!

You will be happiest if you simply accept that there is no ether. That is accepted scientific opinion.

 

[Whitedragon]

but before i don't accept it, I want to know what it was considered to be. What people thought it was. Before i can judge something i must fully understand it.

 

[Doc Al]

At one time it was thought that light (electromagnetic waves) required a medium in which to travel, much like sound requires a medium. That medium was called the aether. As Dr. C says, it is no longer believed to exist.

 

[Whitedragon]

why is it no longer considered to exist?

 

[Poncho]

If there is no way to detect it, it serves no purpose in the theory.

 

[Whitedragon]

So were not sure wether or not that light has a mediem? If every other wave has one then surely light would?

 

[Tom Mattson]

It's not that we know that the aether doesn't exist. It's that the aether is superfluous. It isn't needed to account for anything that has been observed.

 

[Whitedragon]

Makes sense i quess, but i still don't like the fact that we don't have an answer to how light travels. It desterbs me greatly.

 

[Poncho]

You're gonna hate quantum mechanics.

 

[Whitedragon]

...we shall see...

 

[Tom Mattson]

Makes sense i quess, but i still don't like the fact that we don't have an answer to how light travels. It desterbs me greatly.

Sure we do, light travels by electromagnetic induction. Changing electric fields induce magnetic fields, and vice versa. When the fields are sinusoidal in both time and space, you get a monochromatic EM wave.

 

[Whitedragon]

Ah! Brialliant! But I though electromagatism is a field not a substance.

 

[Tom Mattson]

Monochromatic light is indeed a sinusoidally varying EM field, and we know its dynamics (in other words "how it travels") very well.

 

[pervect]

There are basically two approaches one can take to reality.

One can study it on the basis of what one can measure. This is science.

One can argue about things that one can never measure. This is philosophy.

We can measure a great deal about light and gravity. This has lead us to our current scientific knowledge about both.

If you are interested in science, you would do well to study and think about thingks that can actually be measured, and put your philosophical questions on the back burner. You do not have to abandon them entirely, but you have to be able to recognize which questions can be tested by observation (are scientific), and which questions cannot be tested by observation (philosophical). Perhaps someday one realizes that a question one thought could not be tested can in fact be tested - at that point, the question leaves the relm of philosophy, and enters the realm of science.

Sometimes, oddly enough, people put philosophy first. They set up preconcieved notions of how reality "ought to be", in their personal opinion. They then rail against the scientific establishment when it rudely points out that that's not how reality has actually been observed to behave.

 

[Ki Man]

so what we are talking about here is a medium other than the one we are in right now that light must travel though before reaching its final destination?

if its anything like that then no its not real and does not exist. it is impossible.

 

[DrChinese]

It desterbs me greatly.

Ha, I said you be happier if you accepted my answer...

The question of "what does light travel through" is an artificial problem anyway. Why would it need to travel though anything? You can ask any number of similar questions (such as "why is water wet?"). Rather than get distracted by the questions we can ask, it is fruitful to focus on questions that get us to the next stage of our understanding.

As to the existence of the ether: if you change your definition enough, you can simply say that spacetime itself is the ether. Or phase space, or the quantum vacuum. Those are perfectly acceptable answers. Does that help?

 

[Danger]

They set up preconcieved notions of how reality "ought to be", in their personal opinion. They then rail against the scientific establishment when it rudely points out that that's not how reality has actually been observed to behave.

Aye. Does 'creationism' ring a bell?

 

[Whitedragon]

Ha, I said you be happier if you accepted my answer...

The question of "what does light travel through" is an artificial problem anyway. Why would it need to travel though anything? You can ask any number of similar questions (such as "why is water wet?"). Rather than get distracted by the questions we can ask, it is fruitful to focus on questions that get us to the next stage of our understanding.

As to the existence of the ether: if you change your definition enough, you can simply say that spacetime itself is the ether. Or phase space, or the quantum vacuum. Those are perfectly acceptable answers. Does that help?

I ask questoins to which I want answers. If I ask a question I don't care it it's worth asking, and I don't care if i don't like the answer as long as it's reasonable. I just want to know why things happen.

 

[russ_watters]

I ask questoins to which I want answers. If I ask a question I don't care it it's worth asking, and I don't care if i don't like the answer as long as it's reasonable. I just want to know why things happen.

I know it is disappointing, but sometimes the answer to such questions really is that the question itself is irrelevant, useless, or meaningless.

 

[Intuitive]

but before i don't accept it, I want to know what it was considered to be. What people thought it was. Before i can judge something i must fully understand it.

You can study a little about light here:
http://images.google.com/imgres?imgurl=http://www.sci.sdsu.edu/TFrey/Bio750/ElectroMagRad.gif&imgrefurl=http://www.sci.sdsu.edu/TFrey/Bio750/UV-VisSpectroscopy.html&h=243&w=484&sz=3&tbnid=4tRcWNQCcX4J:&tbnh=63&tbnw=126&hl=en&start=7&prev=/images?q=sinusoidally&svnum=10&hl=en&lr=&sa=G