How would the results of the Michelson and Morley experiment have changed if light was a photon?

trevor borocz johnson

trevor borocz johnson

Registered Senior Member
I see a laser stream of photon's being fired at the beam splitter, and they bounce back to the receiver without traveling along the medium of space and being effected by it. Is that also your answer?
 
Whether you describe light as photons or as electromagnetic waves makes no difference to how light behaves in an interferometer. How could it?
 
James R said:
Whether you describe light as photons or as electromagnetic waves makes no difference to how light behaves in an interferometer. How could it?
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Well I was initially thinking a photon beam would be influenced by Earth's movement much like if you shot a photon beam in the direction the Earth is moving we would 'catch up' to the beam the same as if it is a wave, but I'm pretty sure I was wrong.
 
trevor borocz johnson said:
Well I was initially thinking a photon beam would be influenced by Earth's movement much like if you shot a photon beam in the direction the Earth is moving we would 'catch up' to the beam the same as if it is a wave, but I'm pretty sure I was wrong.
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Light is influenced by the Earth's effect on the curvature of spacetime, yes.

But that happens whether or not you look at it as a particle or a wave.
 
trevor borocz johnson said:
Well I was initially thinking a photon beam would be influenced by Earth's movement much like if you shot a photon beam in the direction the Earth is moving we would 'catch up' to the beam the same as if it is a wave, but I'm pretty sure I was wrong.
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No. That's exactly the right idea, but it doesn't depend specifically on light being photons. The same argument applies to light waves.

This was exactly the premise behind the Michelson-Morley experiment. Looking at things in the reference frame of the interferometer itself, the effect should theoretically look as if the speed of light varies, depending on the motion of the interferometer through the "ether".

The result of that experiment, of course, was that no variation in the speed of light was observed: a null result. The conclusion is that there's no "ether". Moreover, the result can be explained using Einstein's theory of relativity.
 
James R said:
No. That's exactly the right idea, but it doesn't depend specifically on light being photons. The same argument applies to light waves.

This was exactly the premise behind the Michelson-Morley experiment. Looking at things in the reference frame of the interferometer itself, the effect should theoretically look as if the speed of light varies, depending on the motion of the interferometer through the "ether".

The result of that experiment, of course, was that no variation in the speed of light was observed: a null result. The conclusion is that there's no "ether". Moreover, the result can be explained using Einstein's theory of relativity.
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So for the two boys throwing a ball back and forth on a truck moving 50 mph, is the 'reference frame' of the two boys supposedly the interferometer which only sees the ball being passed back and forth and the ball doesn't observe the truck moving 50 mph? (evidentally the medium the ball is travelling on, air, probably would carry the ball in crazy directions because of the truck's velocity.
 
trevor borocz johnson said:
So for the two boys throwing a ball back and forth on a truck moving 50 mph, is the 'reference frame' of the two boys supposedly the interferometer which only sees the ball being passed back and forth and the ball doesn't observe the truck moving 50 mph? (evidentally the medium the ball is travelling on, air, probably would carry the ball in crazy directions because of the truck's velocity.
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You cannot use any material analogy for light. You will get nonsense results.

An observer on the ground looking at the truck moving past, and an observer on the truck will both measure light moving at the same speed ("c"). A ball - or any object with mass does not behave this way.
 
DaveC426913 said:
An observer on the ground looking at the truck moving past, and an observer on the truck will both measure light moving at the same speed ("c")
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Aw so its just a fancy way of saying light's speed isn't effected by the aether because both observer's see it the same. It's kind of a circular statement. Doesn't really make sense with the fact that light has a speed that can be measured.
 
trevor borocz johnson said:
So for the two boys throwing a ball back and forth on a truck moving 50 mph, is the 'reference frame' of the two boys supposedly the interferometer which only sees the ball being passed back and forth and the ball doesn't observe the truck moving 50 mph?
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Exactly.

Here's another thought experiment for you.

You are having a poop on an airplane. The poo falls out and hits the bowl beneath. Now you, the poo and the bowl are all moving at about 500mph at that point. Does the poo hit the side of the bowl and explode like a grenade since it hit the bowl at 500mph? Or does it just drop into the bowl the way it does on the ground because everything is moving at the same speed?

That's relative motion for you.
 
trevor borocz johnson said:
Aw so its just a fancy way of saying light's speed isn't effected by the aether because both observer's see it the same. It's kind of a circular statement. Doesn't really make sense with the fact that light has a speed that can be measured.
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If light was effected by the ether, then both observers would measure it as moving at c relative to the ether, and measure it's speed relative to themselves vary depending on their own velocity with respect to the ether.
If light behaved as an object behaving by Newtonian rules, both observers would measure light emitted by itself( or a source moving with it) as moving at c relative to themself, but light emitted by a source moving relative to them, would be measured as moving at a speed relative to themselves which would depend on the relative motion of the source.
When Relativity says that all observers measure light as moving at c, it means relative to themselves, regardless of what motion they have, or the motion the source has relative to them.
 
billvon said:
Exactly.

Here's another thought experiment for you.

You are having a poop on an airplane. The poo falls out and hits the bowl beneath. Now you, the poo and the bowl are all moving at about 500mph at that point. Does the poo hit the side of the bowl and explode like a grenade since it hit the bowl at 500mph? Or does it just drop into the bowl the way it does on the ground because everything is moving at the same speed?

That's relative motion for you.
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Relative bowel motion, to be precise.......
 
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