Do high and low energy photons follow the same trajectory around a planet?

In summary: However, just because we haven't measured it doesn't mean there's any doubt about it. If there were no general relativity, we would still know that photons cause spacetime curvature based on the mathematical predictions of the theory. There are many theories that deserve attention but until observations support the math, shouldn't we be careful not to present it as fact?
  • #36
N721YG said:
Frequency is often measured in cycles per second. You can drop down to a straight line, 1 cycle per second frequency."a quantum of excitation of the electromagnetic field" means nothing to me as far as proving light bends spacetime.

Since the whole thing is more or less arm waving, nothing we can define light as can be held to account in a theory of light bending space. If it did though then there should in theory be a discrepancy in the http://en.wikipedia.org/wiki/Michelson-Morley_experiment" [Broken] experiment also, but just how you'd go about setting up something to measure a "particle" like a photons effect on space-time is beyond anyone, even dare I say it the finest minds in physics, so it's a moot point.

Generally we just assume light speed is constant in a vacuum and leave it at that. For the same reason we assume the photon has no mass, because to say otherwise is a matter for philosophy not science.
 
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  • #37
The Dagda said:
nothing we can define light as can be held to account in a theory of light bending space.

As far as I know, classical electrodynamics adapts OK to curved spacetime, and that's what people use when calculating the gravitational effects of light. I've seen references to such calculations here.

It's photons that we have problems with, because we don't have a generally accepted quantum theory of gravity yet.
 
  • #38
The Dagda said:
Since the whole thing is more or less arm waving, nothing we can define light as can be held to account in a theory of light bending space. If it did though then there should in theory be a discrepancy in the http://en.wikipedia.org/wiki/Michelson-Morley_experiment" [Broken] experiment also, but just how you'd go about setting up something to measure a "particle" like a photons effect on space-time is beyond anyone, even dare I say it the finest minds in physics, so it's a moot point.

Generally we just assume light speed is constant in a vacuum and leave it at that. For the same reason we assume the photon has no mass, because to say otherwise is a matter for philosophy not science.

Well said and I second the motion.

What I was looking for earlier, and I get a real DUH for not catching my own mistake. I need to work on making myself clear. :smile:
E=MC^2
mass of Earth * (the speed of light^2) = 5.36934319 × 10^41 joules
 
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  • #39
N721YG said:
Frequency is often measured in cycles per second. You can drop down to a straight line, 1 cycle per second frequency.
It's better if you study again the concept of frequency.
"a quantum of excitation of the electromagnetic field" means nothing to me as far as proving light bends spacetime.
Exactly. So, if you post here what wikipedia or anything else says about photons, doesn't mean anything for what concern that question...
 
  • #40
N721YG said:
Well said and I second the motion.

What I was looking for earlier, and I get a real DUH for not catching my own mistake. I need to work on making myself clear. :smile:
E=MC^2
mass of Earth * (the speed of light^2) = 5.36934319 × 10^41 joules

To be accurate you'd probably need to account for all the different masses, and since it's a massive object it will no doubt be extremely complicated, with various energy interactions not to mention the system is not closed. But in theory I suppose that is correct. Of course this is all hypothetical until I finish constructing my dooms day device, but your calculations are appreciated. :smile:
 
  • #41
lightarrow said:
It's better if you study again the concept of frequency...

I said "Frequency is often measured in cycles per second. You can drop down to a straight line, 1 cycle per second frequency." You may be right though, an oscilloscope measures "0" frequency so 1 may be wrong. This of course is not in the visible light spectrum. Maybe think DC current. :smile: If you have a link that can teach me something please post it.
 
  • #42
The Dagda said:
To be accurate you'd probably need to account for all the different masses, and since it's a massive object it will no doubt be extremely complicated, with various energy interactions not to mention the system is not closed. But in theory I suppose that is correct. Of course this is all hypothetical until I finish constructing my dooms day device, but your calculations are appreciated. :smile:

Actually I let google do all my math since it knows all about the mass of Earth and the speed of light. You probably already know this but anyone who doesn't, just copy and paste (mass of earth)c^2 into google search and hit enter. There are more meaningful and more complicated equations it can work with.

I am glad that I am not the only one building a dooms day device. Most of my friends think I am nuts. :biggrin:
 
  • #43
N721YG said:
Actually I let google do all my math since it knows all about the mass of Earth and the speed of light. You probably already know this but anyone who doesn't, just copy and paste (mass of earth)c^2 into google search and hit enter. There are more meaningful and more complicated equations it can work with.

I am glad that I am not the only one building a dooms day device. Most of my friends think I am nuts. :biggrin:

Well that's not a problem for me as I have gotten rid of my friends, if you know what I mean, they knew too much!
 
  • #44
N721YG said:
I said "Frequency is often measured in cycles per second. You can drop down to a straight line, 1 cycle per second frequency." You may be right though, an oscilloscope measures "0" frequency so 1 may be wrong. This of course is not in the visible light spectrum. Maybe think DC current. :smile: If you have a link that can teach me something please post it.
There is no need of links, just think that frequency is 1/T (T = period of oscillation) so if something, included EM fields, takes more than 1 second to complete the oscillation, the frequency is lower than 1 Hz. Take a point charge and put it on the border of a disk and rotate the disk at constant speed so that it takes 2 seconds to make one rev. Then the EM field generated has a frequency of 0.5Hz.
 
  • #45
lightarrow said:
There is no need of links, just think that frequency is 1/T (T = period of oscillation) so if something, included EM fields, takes more than 1 second to complete the oscillation, the frequency is lower than 1 Hz. Take a point charge and put it on the border of a disk and rotate the disk at constant speed so that it takes 2 seconds to make one rev. Then the EM field generated has a frequency of 0.5Hz.

Didn't I correct myself in my last post when I said "You may be right though, an oscilloscope measures "0" frequency so 1 may be wrong."? So I believe a straight line would be 0 hz.
 
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  • #46
N721YG said:
Didn't I correct myself in my last post when I said "You may be right though, an oscilloscope measures "0" frequency so 1 may be wrong."? So I believe a straight line would be 0 hz.
Ok, I didn't write that to show you again that you are incorrect :smile: I just meant to show you how I reasoned about it (then you can use the information as you prefer...)
 

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