Curving light waves

Originally posted by primalfractal

Thanks, I think I might be to. I argued it out with my dad who is a physics
phd, after a bit he couldn't point out anything wrong with the theory but still
disagreed lol.

Of course he did..The "student" is "never" right Thanks for the links..I just love this kind of stuff and learning new things about it..Almost to the point of obsession

reply to post by TheLonewolf


Just took a better look at your avatar.
We are discussing the bit where the cat folds
in on itself

Glad you liked the info, I'm also a bit obsessed by these topics
but I think they are the important questions, better than reality
tv thats for sure.

You can't do Newtonian relative-velocity calculations with light. It always travels with the same velocity, and always in straight lines unless its path is distorted by gravity or a transition between media. Neither of those effects, nor the illusion described in the Science News link, have anything to do with the OP description.

reply to post by Astyanax


Thanks for answering. I am aware of the dogma regarding light.
Can you please point out how exactly the OP is wrong? Quite happy to
be proved wrong but that will take a logical flaw in the theory.
Just saying light goes straight doesn't refute what I'm saying.

Sorry, all.

reply to post by primalfractal

Can you please point out how exactly the OP is wrong?

Sure. If you shine a laser at a point on Earth from the Moon (or vice versa), you will have to keep adjusting the orientation of the laser in order to keep targeting that point, otherwise the relative movements of Earth and Moon will cause it to drift.

Since a laser is a very narrow beam of coherent light, the light source will cease to be visible when it has drifted off target. You can't see a laser beam unless it is pointed right at you. You will, however, see its ionization path through Earth's atmosphere. It will show as a straight line, not as a curve.

This is before we even get into the whole frame-of-reference discussion. Your analogy from Newtonian conditions (bullets being shot from a train) uses the frame of reference of somebody aboard the train. To such an observer, the path of the bullet is the vector sum of the motion of the bullet and the motion of the earth relative to the train. One of those vectors has a value that changes over time – the bullet decelerates – and so the apparent path is parabolic (ignoring the effect of gravity, which imposes a second parabola at right angles to the first). But light is not slowed down or appreciably diverted by a gravity field as weak as Earth's. It will continue to propagate in a straight line.

This is not a question in relativity, by the way; to make it one, Earth and the Moon would have to be moving at a substantial fraction of the speed of light relative to one another.

Oh, and science is not dogma, although it may seem like that to those ignorant of it.

reply to post by Astyanax

Originally posted by primalfractal
Thanks, I think I might be to. I argued it out with my dad who is a physics
phd, after a bit he couldn't point out anything wrong with the theory but still
disagreed lol.

Astyanax is right as usual, thanks Astyanax.

primalfractal, could it be that your dad just got tired of arguing with you? I wouldn't presume his giving up as an admission that nothing is wrong with your idea.

Originally posted by Astyanax
Oh, and science is not dogma, although it may seem like that to those ignorant of it.

Science can seem very dogmatic to those with no evidence to support novel ideas.

But for those with verifiable, repeatable evidence, it's not dogmatic at all as seen in 1998 when evidence of "dark energy" was first presented. It probably took five years and further replications for people to get on board with it, but almost all cosmologists now accept the evidence and admit the pre-1998 models were probably wrong. This is not dogma. It's the way science works.

reply to post by Astyanax


Cool answer, sorry about the dogma thing, bit of a low blow and not really true. Science does have some solutions.

If you shine a laser at a point on Earth from the Moon (or vice versa), you will have to keep adjusting the orientation of the laser in order to keep targeting that point, otherwise the relative movements of Earth and Moon will cause it to drift.

This is true but to keep the laser on target I would have to point it in the direction the target will be in 1.282 sec when the light reaches earth. So if you were to instantly follow the light to its source it would have to curve.

Another analogy would be if I went away from you with a laser continually pointed at you, on reaching the moon (this could be easily reduced in scale) I am still shining the laser at you but it is now pointing where you will be in 1.282 sec. If you follow the beam, doesn't it go to its source? This doesn't describe a straight line.

As far as frame of reference goes I am using the beam itself.

reply to post by Arbitrageur

primalfractal, could it be that your dad just got tired of arguing with you? I wouldn't presume his giving up as an admission that nothing is wrong with your idea.

Sorry but you dont know him or me. Instead of personally insulting me by labelling me presumtuous prehaps you could contribute some of the science you are so fond of?

Originally posted by primalfractal
This is true but to keep the laser on target I would have to point it in the direction the target will be in 1.282 sec when the light reaches earth. So if you were to instantly follow the light to its source it would have to curve.

Another analogy would be if I went away from you with a laser continually pointed at you, on reaching the moon (this could be easily reduced in scale) I am still shining the laser at you but it is now pointing where you will be in 1.282 sec. If you follow the beam, doesn't it go to its source? This doesn't describe a straight line.

As far as frame of reference goes I am using the beam itself.

The beam isn't a reference frame. The beam is a series of photons, which, if you're changing the direction, the photons are going in different directions. A reference frame can't have multiple directions simultaneously.

Just because the photons can be arranged in a curve, doesn't mean they aren't traveling in a straight line. If you took a machine gun, and fired a bullet, then re-aimed the gun a little to the right, fired another bullet, then re-aimed more to the right and fired another bullet and so on, if you do this fast enough and look at the pattern of bullets from above, the bullets can each be going in a straight line, but can form an arc or a curve. This doesn't mean the bullets are traveling a curved path. Do you understand the difference?

Originally posted by primalfractal
Sorry but you dont know him or me. Instead of personally insulting me by labelling me presumtuous prehaps you could contribute some of the science you are so fond of?

I do indeed know something about you from reading your posts. One thing is that your reading comprehension isn't that great because my reference to presumption referred to what presumptions I would or would not make. I didn't label you presumptuous.

reply to post by Arbitrageur


Haha I'm not talking about particles/photons. From the OP

But I’m not talking about particles, I’m talking about waves.

This from you.

Just because the photons can be arranged in a curve, doesn't mean they aren't traveling in a straight line. If you took a machine gun, and fired a bullet, then re-aimed the gun a little to the right, fired another bullet, then re-aimed more to the right and fired another bullet and so on, if you do this fast enough and look at the pattern of bullets from above, the bullets can each be going in a straight line, but can form an arc or a curve. This doesn't mean the bullets are traveling a curved path. Do you understand the difference?

My machine gun referance was to show what this theory wasn't.

So from your post I would guess you cant read or understand a basic concept and if you refer to particles again I will have to conclude you are retarded(from your posts that is).

reply to post by primalfractal

Just because I referred to photons doesn't mean they aren't waves. You could think of them as wave packets as this illustration shows:

abyss.uoregon.edu...

So a photon, or a free moving electron, can be thought of as a wave packet, having both wave-like properties and also the single position and size we associate with a particle.

reply to post by Arbitrageur

As far as frame of reference goes I am using the beam itself

Sorry, this was a rather cryptic joke about Einstien.

I like the wave packet description and the animation, thank you for taking the time and coming up with something good.

So a photon, or a free moving electron, can be thought of as a wave packet, having both wave-like properties and also the single position and size we associate with a particle.

The machine gun analogy describes the single position portion of the wave packet. I am trying to describe the wave-like properties.

reply to post by primalfractal


I do have to side with Arbitrageur. You seem to misunderstand the whole wave particle duality thing.

Photons are electromagnetic packets of energy like Arbitrageur has explained, these are as far as we know, zero mass, and thus they travel at the speed of light... yep photons being light and travelling at that speed... shock horror.

Now the same thing can be applied to electrons which have a de Broglie wavelength also... now if you fire electrons at a constant rate without being in an electric field they or slowing down due to energy loss, will just travel in a straight line. If you sweep the source to the side, depending on the frame of reference you can observe (if you draw dot to dot) that if you freeze time, the positions of the electrons will make a curve... it does NOT however mean that the path of the electrons IS a curve.

This is exactly the same for the photons each photon is a separate entity, yes they are coherent that when you look at the waveform looks like you are observing a single continuous waveform, but it is still composed of individual photons that are independent of each other.

Having to track the moon again is a case of hitting a target and the finite speed of light. The finite speed of light requires you to predict where the target will be ahead of time. It is exactly the same as firing a gun, it does not mean the actual path of light is curved though.

Once again, i cant help but feel that this has been explained to death, and you simply are ignoring that scientifically logical answers have been provided and you simply refuse to understand them, or accept them as the case.

The wave-like properties are the wavepacket part of the particle... not a macroscopic observation of the paths of billions of independent photons

Sorry to appear to be offensive, but I often feel like people too often come across this issue when trying to explain things.

reply to post by primalfractal

I'm glad you liked the wave packet. One thing that's relevant in sending light waves from the earth to the moon is the length of the wave packet:

www.physicsforums.com...

I think the record coherence time for a solid state single photon source is around 22 ns (Matthiesen et al., PRL 108, 093602 (2012)prl.aps.org...)....

prl.aps.org...
This corresponds to about 7 meters, and this is a very long wave packet (perhaps a record length as the author speculates); most would probably be less than 1 meter long, but this will depend on your light source. Therefore the wave packet length typically won't reach all the way from the earth to the moon, so this should be a consideration in your analysis. If you see a light beam going from the Earth to the moon, it's actually a series of these wave packets.

what makes you think YOU get to decide whether or not you are talking about light-as-particle or light-as-wave?

the particle/wave duality depends entirely upon the measurement method. in the case of your OP, you have selected an experiment in which light will appear to be quantized. in fact, the way you have set it up is a very good justification for the quantized nature of light. in order to NOT BE CURVED (which it is not), it HAS TO BE quantized.


another way: hey, lets set up a double slit experiment, releasing one photon at a time..,.and then in the middle of the experiment, we will move the photon gun.....and then because light moves from "alpha to omega" (what that is supposed to mean I have no idea), we will demand to speak of its wave properties.

ummmm....no. the light, in your example, is quantized....you don't get to choose.

reply to post by tgidkp

what makes you think YOU get to decide whether or not you are talking about light-as-particle or light-as-wave?

we will demand to speak of its wave properties.

This is rather funny but scary(for you) - thought police anyone? This is a hypothetical explanation of a possible theory, not scientific experiment. I cant decide to talk about light as a wave? Is this a joke?

As far as frame of reference goes I am using the beam itself

My Einstein pun hypothetically covers the observation dilema, by "sitting on the beam" or using it as a frame of referance you can know where it goes without it quantitizing. Worked for him and the Zen guys.

Dont know how you would set up an actual experiment but I think it is possible.

"alpha to omega" (what that is supposed to mean I have no idea)

No one likes a liar

reply to post by Arbitrageur

This corresponds to about 7 meters, and this is a very long wave packet (perhaps a record length as the author speculates); most would probably be less than 1 meter long, but this will depend on your light source. Therefore the wave packet length typically won't reach all the way from the earth to the moon, so this should be a consideration in your analysis. If you see a light beam going from the Earth to the moon, it's actually a series of these wave packets.

I think you are right here, the effect would include a series of wave packets. Prehaps shrinking the initial distance of the hypothesis down to the size of an individual wave packet length would be simpler to explain and also make quantitization issues in an actual experiment easier to handle.

hahaha! you are too much! here, let me sum up the last three posts:

ME: you are having quantization issues.
YOU (to me): thought police!
YOU (to arbitrageur): you know, i think i am having quantization issues.

----->nice job, sherlock.
_______________________

"....if you refer to particles again I will have to conclude you are retarded."

WRT "thought police", you certainly can think whatever you want. but if you want to describe reality, then you cant decide to describe the sun as a purple elephant and if we do not agree then we are "retarded". actually, there is a description of the double-slit (single photon) experiment as a wave, but it is not what you would normally refer to as a "wave", rather, it is a waveFUNCTION. i think this may be the piece of information you are missing: the wavefunction is the only wave that exists in quantum mechanics.

WRT "alpha and omega", i really seriously have never heard these terms used in a scientific context. the best i can do is that maybe you are referring to the PHI and THETA angles from the spherical cooridinate system. you have your greek mixed up????

WRT einsteins "riding the beam", unless i am mistaken in this case he is discussing relativity, not quantum mechanics. these two theories have not yet been reconciled....QM requires a strict frame of reference (a "basis") and in relativity there is no strict frame. so relativistically, if you are riding the beam then the beam is FOR SURE not curved....the beam is a straight line and the moon/space/earth becomes expanded/contracted in length/time.


good luck!

reply to post by tgidkp

In classical physics, as I am sure you know, light is thought of as a wave. However, this doesn't help the OP's case (or his stance with respect to wave-particle duality) at all.