The Naked Scientists
  • Login
  • Register
  • Podcasts
      • The Naked Scientists
      • eLife
      • Naked Genetics
      • Naked Astronomy
      • In short
      • Naked Neuroscience
      • Ask! The Naked Scientists
      • Question of the Week
      • Archive
      • Video
      • SUBSCRIBE to our Podcasts
  • Articles
      • Science News
      • Features
      • Interviews
      • Answers to Science Questions
  • Get Naked
      • Donate
      • Do an Experiment
      • Science Forum
      • Ask a Question
  • About
      • Meet the team
      • Our Sponsors
      • Site Map
      • Contact us

User menu

  • Login
  • Register
  • Home
  • Help
  • Search
  • Tags
  • Member Map
  • Recent Topics
  • Login
  • Register
  1. Naked Science Forum
  2. Non Life Sciences
  3. Physics, Astronomy & Cosmology
  4. Does a photon self propagate due to the interactions of the electric and magnetic fields?
« previous next »
  • Print
Pages: [1] 2   Go Down

Does a photon self propagate due to the interactions of the electric and magnetic fields?

  • 22 Replies
  • 2048 Views
  • 0 Tags

0 Members and 1 Guest are viewing this topic.

Offline jeffreyH (OP)

  • Global Moderator
  • Naked Science Forum King!
  • ********
  • 6807
  • Activity:
    0%
  • Thanked: 174 times
  • The graviton sucks
    • View Profile
Does a photon self propagate due to the interactions of the electric and magnetic fields?
« on: 14/05/2019 18:36:21 »
It might be useful to try to answer this question. Does a photon self propagate due to the interactions of the electric and magnetic fields? Taking into consideration the wavelike nature of the photon.
Logged
Even the most obstinately ignorant cannot avoid learning when in an environment that educates.
 



Offline Bogie_smiles

  • Naked Science Forum King!
  • ******
  • 1064
  • Activity:
    0%
  • Thanked: 59 times
  • Science Enthusiast
    • View Profile
Re: Does a photon self propagate due to the interactions of the electric and magnetic fields?
« Reply #1 on: 15/05/2019 02:28:05 »
Some sources say that the photon is both wave like and particle like, depending on the method of observation.
Logged
Layman Science Enthusiast
 

Offline Colin2B

  • Global Moderator
  • Naked Science Forum King!
  • ********
  • 5248
  • Activity:
    27.5%
  • Thanked: 430 times
    • View Profile
Re: Does a photon self propagate due to the interactions of the electric and magnetic fields?
« Reply #2 on: 15/05/2019 06:48:06 »
Quote from: Bogie_smiles on 15/05/2019 02:28:05
Some sources say that the photon is both wave like and particle like, depending on the method of observation.
All reliable sources say this.
How does this relate to the topic?
Logged
and the misguided shall lead the gullible,
the feebleminded have inherited the earth.
 

Offline Bogie_smiles

  • Naked Science Forum King!
  • ******
  • 1064
  • Activity:
    0%
  • Thanked: 59 times
  • Science Enthusiast
    • View Profile
Re: Does a photon self propagate due to the interactions of the electric and magnetic fields?
« Reply #3 on: 15/05/2019 12:20:52 »
Quote from: jeffreyH on 14/05/2019 18:36:21
It might be useful to try to answer this question. Does a photon self propagate due to the interactions of the electric and magnetic fields? Taking into consideration the wavelike nature of the photon.
Some sources say that the photon is both wave like and particle like, depending on the method of observation.


Quote from: Colin2B on 15/05/2019 06:48:06
All reliable sources say this.
How does this relate to the topic?

I was responding to jeffreyH’s comment, quoted above, about the propagation of a photon, i.e., in the form of the particle and the wave…

Is the photon particle itself “light”, or does the photon, which is made up of multiple quanta of energy contained in the photon particle, emit electromagnetic wave energy, which is “light”?

It looked like the thread was continuing into that discussion.
Logged
Layman Science Enthusiast
 

Offline Colin2B

  • Global Moderator
  • Naked Science Forum King!
  • ********
  • 5248
  • Activity:
    27.5%
  • Thanked: 430 times
    • View Profile
Re: Does a photon self propagate due to the interactions of the electric and magnetic fields?
« Reply #4 on: 15/05/2019 14:59:12 »
I’ve split this off from the relativity thread as it’s now moving away from that topic.

Quote from: Bogie_smiles on 15/05/2019 12:20:52
Is the photon particle itself “light”,
If you fire a single photon at a photographic film then, as long as the film is sensitive to that frequency, it will register a spot. Same for any detector sensitive to that frequency including the eye. So, we assume the photon is light.

Quote from: Bogie_smiles on 15/05/2019 12:20:52
or does the photon, which is made up of multiple quanta of energy contained in the photon particle, emit electromagnetic wave energy, which is “light”?
The photon is a single quantum it does not contain multiple quanta.
It does not emit anything, it is an oscillating em field disturbance moving through space.

The photon displays wave properties eg diffraction/interference and particle properties eg transfer of momentum.
Logged
and the misguided shall lead the gullible,
the feebleminded have inherited the earth.
 
The following users thanked this post: Bogie_smiles



Offline geordief

  • Sr. Member
  • ****
  • 421
  • Activity:
    0%
  • Thanked: 7 times
    • View Profile
Re: Does a photon self propagate due to the interactions of the electric and magnetic fields?
« Reply #5 on: 15/05/2019 16:07:15 »
If we fire a photon  of a particular frequency at a sensor in the vicinity of the Sun (say,exactly 1000 light seconds-so  about twice the distance)  can we say that both the magnetic field and the electric field  would "wobble" there   in a  way that is a function of the photon's associated wave at that point as the photon passed by?

And could  the size of this "wobble" also  be increased if several photons of the same wavelength were travelling together ? (ie as  a laser,I think)
« Last Edit: 15/05/2019 16:16:23 by geordief »
Logged
 

Offline Janus

  • Hero Member
  • *****
  • 756
  • Activity:
    7.5%
  • Thanked: 180 times
    • View Profile
Re: Does a photon self propagate due to the interactions of the electric and magnetic fields?
« Reply #6 on: 15/05/2019 16:26:35 »
To add to what Colin2B has already said.  A photon, being a quantum of electromagnetic radiation, is the smallest divisible unit of radiation energy you can have for EMR of a given wavelength. 

And, as pointed out, if a single photon strikes photographic paper, it produces a single localized spot. ( like a particle would).
However, if you send a series of single photons, one at a time, through a double slit interferometer, While each individual photon will produce a localized dot on the paper,   The pattern formed after many photons have passed through will be an interference pattern like you would expect from a wave.
A classical particle would not create the interference pattern,  while with a classical wave, you'd get the interference pattern, but it wouldn't be formed from individual dots.( the whole pattern would form at once and just get more distinct as more light passed through the slits. 
While you will hear it said that exhibits both the properties of particles and waves, it is probably more accurate to say that the classical distinction between wave and particle just doesn't hold, and that this becomes more apparent at the quantum level.
This characteristic is not limited to light alone.  Electrons( original considered classical particles) show the same behavior.  You can pass them through a diffraction grating and produce an interference pattern composed of individual dots also.
It is something built into the universe at that scale and not something exclusive to this or that "particle". 
Logged
 
The following users thanked this post: Bogie_smiles

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • 27425
  • Activity:
    100%
  • Thanked: 64 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
Re: Does a photon self propagate due to the interactions of the electric and magnetic fields?
« Reply #7 on: 15/05/2019 16:55:07 »
In what way would it self propagate Jeffrey? Don't you then need to add something else to it?
Logged
"BOMB DISPOSAL EXPERT. If you see me running, try to keep up."
 

Offline Bill S

  • Naked Science Forum King!
  • ******
  • 3631
  • Activity:
    0%
  • Thanked: 108 times
    • View Profile
Re: Does a photon self propagate due to the interactions of the electric and magnetic fields?
« Reply #8 on: 15/05/2019 17:13:55 »
Quote from: Jeffrey
Does a photon self propagate due to the interactions of the electric and magnetic fields? Taking into consideration the wavelike nature of the photon.

Quote from: Colin
If you fire a single photon at a photographic film then, as long as the film is sensitive to that frequency, it will register a spot. Same for any detector sensitive to that frequency including the eye. So, we assume the photon is light.

This raises a few questions:

1. Does the photon propagate, or does the EM energy propagate only as a wave? 

2. In the same way that sound waves are vibrations, that become sound only when interpreted by the appropriate auditory organs; could the same thing be true of light? 
I.e. the radiation travels as “waves” of energy.  Only when “observed” can it be considered as light.  It then appears as a spot. 
No “ears”, no sound, no “observer”, no light. (?)

3. What is the nature of the “interactions of the electric and magnetic fields”?
Logged
There never was nothing.
 



Offline alancalverd

  • Global Moderator
  • Naked Science Forum GOD!
  • ********
  • 11034
  • Activity:
    100%
  • Thanked: 635 times
  • life is too short to drink instant coffee
    • View Profile
Re: Does a photon self propagate due to the interactions of the electric and magnetic fields?
« Reply #9 on: 15/05/2019 17:25:26 »
Electromagnetic radiation propagates according to Maxwell's equations,which are based on the observation that a moving charge creates a magnetic field (see any electromagnet) and a varying magnetic field induces charge (see any dynamo).

The electromagnetic spectrum is continuous but some sources of em radiation emit discrete quanta with a specific frequency.

The "observer" is irrelevant since the photon, phonon or whatever has no concept of observation and the source, which may be a few billion light years away, really doesn't care what happens to the energy it radiates.

Sound is longitudinal pressure waves of any frequency in any medium. The effect of a sound wave has nothing to do with the auditory system. You can play your violin in front of an audience of bats, humans and neurologically deaf humans - the effect on their tympani and auditory ossicles is exactly the same, and the same on a microphone diaphragm that converts it to an electrical signal. The violin and the connecting air have no interest in the nature or presence of a receiver.
« Last Edit: 15/05/2019 17:33:01 by alancalverd »
Logged
helping to stem the tide of ignorance
 
The following users thanked this post: Bill S

Offline Bill S

  • Naked Science Forum King!
  • ******
  • 3631
  • Activity:
    0%
  • Thanked: 108 times
    • View Profile
Re: Does a photon self propagate due to the interactions of the electric and magnetic fields?
« Reply #10 on: 15/05/2019 19:50:05 »
Thanks Alan. There are a few points I will return to, but it may be a day or so; in which case, I wouldn't want to appear unappreciative.
Logged
There never was nothing.
 

Offline jeffreyH (OP)

  • Global Moderator
  • Naked Science Forum King!
  • ********
  • 6807
  • Activity:
    0%
  • Thanked: 174 times
  • The graviton sucks
    • View Profile
Re: Does a photon self propagate due to the interactions of the electric and magnetic fields?
« Reply #11 on: 15/05/2019 20:21:08 »
Quote from: yor_on on 15/05/2019 16:55:07
In what way would it self propagate Jeffrey? Don't you then need to add something else to it?

Well why is it moving at all in that case? The speed of the photon in vacuum could have been variable but it isn't. There is an upper limit. It has to be because of the properties of the electromagnetic field itself. So we are back to the interactions of electric and magnetic fields. Please refer to Alan's post above.
Logged
Even the most obstinately ignorant cannot avoid learning when in an environment that educates.
 

Offline Bill S

  • Naked Science Forum King!
  • ******
  • 3631
  • Activity:
    0%
  • Thanked: 108 times
    • View Profile
Re: Does a photon self propagate due to the interactions of the electric and magnetic fields?
« Reply #12 on: 17/05/2019 21:23:42 »
Quote from: Alan
The "observer" is irrelevant since the photon, phonon or whatever has no concept of observation….

As we are dealing with quantum scale objects (photons); this does seem a restricted interpretation of “observer”. 
Do quantum particles have a “concept of observation” ?

Quote
Sound is longitudinal pressure waves of any frequency in any medium.

Looked at another way, we could say that “longitudinal pressure waves of any frequency in any medium” are defined as sound, because the most readily observable examples are converted to sound by auditory systems. 
Logged
There never was nothing.
 



Offline Colin2B

  • Global Moderator
  • Naked Science Forum King!
  • ********
  • 5248
  • Activity:
    27.5%
  • Thanked: 430 times
    • View Profile
Re: Does a photon self propagate due to the interactions of the electric and magnetic fields?
« Reply #13 on: 17/05/2019 22:58:38 »
Quote from: Bill S on 15/05/2019 17:13:55
1. Does the photon propagate, or does the EM energy propagate only as a wave? 
Don’t understand the question. The photon is the smallest energy unit (quantum) of the wave. As @Janus said, it has wave properties.

Quote from: Bill S on 15/05/2019 17:13:55
2. In the same way that sound waves are vibrations, that become sound only when interpreted by the appropriate auditory organs; could the same thing be true of light? 
I.e. the radiation travels as “waves” of energy.  Only when “observed” can it be considered as light.  It then appears as a spot. 
No “ears”, no sound, no “observer”, no light. (?)
I’m with Alan on this one. Philosophical questions often come down to poor definition of terms or misunderstanding physics and this is a classic example.

Quote from: Bill S on 17/05/2019 21:23:42
As we are dealing with quantum scale objects (photons); this does seem a restricted interpretation of “observer”. 
Do quantum particles have a “concept of observation” ?
No, of course not, how could it. In QM observation is synonymous with taking a measurement. How you take that measurement determines whether you see wave or particle behaviour.
Your question is similar to asking whether ocean waves have a concept of breaking on the shore, it makes no sense.

Quote from: Bill S on 15/05/2019 17:13:55
.....because the most readily observable examples are converted to sound by auditory systems. 
Infrasound? Ultrasound?
Even bats can’t hear the ultrasound used in maternity scanners or therapeutic ultrasound.
Logged
and the misguided shall lead the gullible,
the feebleminded have inherited the earth.
 

Offline evan_au

  • Global Moderator
  • Naked Science Forum GOD!
  • ********
  • 9019
  • Activity:
    76%
  • Thanked: 886 times
    • View Profile
Re: Does a photon self propagate due to the interactions of the electric and magnetic fields?
« Reply #14 on: 18/05/2019 02:08:24 »
Quote from: OP
Does a photon self propagate due to the interactions of the electric and magnetic fields?
Yes.

Quote from: alancalverd
a moving charge creates a magnetic field (see any electromagnet) and a varying magnetic field induces charge (see any dynamo).
Quote from: jeffreH
Well why is it moving at all in that case?
To see why it is moving in a particular direction, you can look at the source:

When an excited electron drops to a lower energy level of an atom, it emits a photon of a characteristic energy/frequency/wavelength, but in a random direction.
- The quantum transition creates the conditions of a changing electric field (the electron changing orbital) which induces a changing magnetic field, which in turn induces a changing electric field.
- In the "near field" (close to the atom), the electric field of the electron remains bound to the atom.
- But part of those changing electric and magnetic fields detach from the atom, creating "far field" conditions. This energy propagates away from the atom "to infinity" (or until it runs into something).
- Conservation of energy ensures that the photon has the characteristic energy
- But quantum uncertainty in the position of the electron means that the direction must be very uncertain
- Once an electromagnetic wave starts propagating in a particular direction, the conditions of the electric and magnetic fields in front, behind and in the middle interact to ensure that it keeps moving in that direction.
- The speed that it moves depends on the permeability and permittivity of whatever it is propagating through (including a vacuum). This can be considered as the capacitance and inductance of the medium  (including a vacuum).
- These parameters affect the extent to which a changing electric field produces a magnetic field, and the extent to which a changing magnetic field produces an electric field.

There are some exceptions where it changes direction:
- If the light hits a mirror, the current induced in the metal surface cancels the incoming electric field, and produces an outgoing photon which follows the laws of reflection.
- If you change into a different medium (eg air to glass), the permittivity of the medium changes (glass has a higher permittivity, and the speed of light is lower). This changes the direction of the light, according to the laws of refraction.
- If the "wavicle" strikes a dual slit, it interferes with itself, and it's final direction will be more likely in some directions than others, creating an interference pattern.
- If you change into a stronger gravitational field (eg near a black hole), time dilation causes the direction to bend.
 
Different sources of light produce different kinds of light with different characteristics:
- Movement of electrons driven at different rates by a crystal oscillator (eg in a WiFi router) produces light/radio waves of different frequencies.
- Random movements of atoms above absolute zero produce black body radiation, which is emitted in all directions with a characteristic spectrum
- In a laser, quantum effects produce light which is almost monochromatic, and interference produces light which has low divergence (diffraction-limited)
Logged
 

Offline alancalverd

  • Global Moderator
  • Naked Science Forum GOD!
  • ********
  • 11034
  • Activity:
    100%
  • Thanked: 635 times
  • life is too short to drink instant coffee
    • View Profile
Re: Does a photon self propagate due to the interactions of the electric and magnetic fields?
« Reply #15 on: 18/05/2019 11:14:29 »
Quote from: Bill S on 17/05/2019 21:23:42
As we are dealing with quantum scale objects (photons); this does seem a restricted interpretation of “observer”.  Do quantum particles have a “concept of observation” ?
The only things in the universe that have a concept of observation are the humans who write excessively anthropic physics texts!

The fundamental principle of physics is that stuff happens consistently throughout the universe. This is an implicit belief of everyone except corrupt Health and Safety Executive inspectors and devotees of religion. Humans have not been around very long in cosmic terms, but the quantum phenomena we observe to have happened in other galaxies, millions of years before life evolved on Earth, are entirely consistent  with those we observe to be happening here and now, so the observer has no role in it.

That does not preclude the role of an "observation" in modifying what is observed, and this is where you need to be very careful in the use of language.  Heisenberg's thought experiments concern locating an electron in space and time. The only way to do this is to ping a photon off it, but in doing so you will transfer energy and momentum to the electron and thus alter the numbers you wanted to determine. From which he produced the principle of indeterminacy, which is probably the most important and most misinterpreted insight ever made!
Logged
helping to stem the tide of ignorance
 

Offline jeffreyH (OP)

  • Global Moderator
  • Naked Science Forum King!
  • ********
  • 6807
  • Activity:
    0%
  • Thanked: 174 times
  • The graviton sucks
    • View Profile
Re: Does a photon self propagate due to the interactions of the electric and magnetic fields?
« Reply #16 on: 18/05/2019 12:02:05 »
Quote from: evan_au on 18/05/2019 02:08:24
- If the "wavicle" strikes a dual slit, it interferes with itself, and it's final direction will be more likely in some directions than others, creating an interference pattern.

People should read this point over a few times. Then we might get less nonsense spouted about the double slit experiment. Thanks for posting this Evan.
Logged
Even the most obstinately ignorant cannot avoid learning when in an environment that educates.
 



Offline Bill S

  • Naked Science Forum King!
  • ******
  • 3631
  • Activity:
    0%
  • Thanked: 108 times
    • View Profile
Re: Does a photon self propagate due to the interactions of the electric and magnetic fields?
« Reply #17 on: 19/05/2019 16:02:26 »

Quote from: Colin
Don’t understand the question. The photon is the smallest energy unit (quantum) of the wave. As @Janus said, it has wave properties.

I’m not arguing with that.  Sometimes one sees the assertion that light travels as a wave, but is “detected” as a photon.  I was looking for opinions on that idea.

 
Quote from: Bill
No “ears”, no sound, no “observer”, no light. (?)

Quote from: Colin
I’m with Alan on this one. Philosophical questions often come down to poor definition of terms or misunderstanding physics and this is a classic example.

I’ve long suspected that semantics could be blamed for much misunderstanding. Perhaps this comes down to the point at which we define longitudinal pressure waves as sound, or EMR as light.
Quote from: Bill
.....because the most readily observable examples are converted to sound by auditory systems.

Quote from: Colin
Infrasound? Ultrasound?
Even bats can’t hear the ultrasound used in maternity scanners or therapeutic ultrasound.

All I meant was that because people were hearing sounds, long before anyone knew about sound waves, the popular definition of sound might be that which is audible to the human ear.  This might be extended to those wavelengths that can be heard by various animals, etc. but is there a point beyond which these waves might not be defined as sound?

A similar question could be asked about light; especially in view of definitions such as “Light is a transverse, electromagnetic wave that can be seen by the typical human.”   https://physics.info/light/
Logged
There never was nothing.
 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • 27425
  • Activity:
    100%
  • Thanked: 64 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
Re: Does a photon self propagate due to the interactions of the electric and magnetic fields?
« Reply #18 on: 19/05/2019 16:11:11 »
No Jeffrey
Ask how light can 'propagate' instead.

Don't look at the equations
Logged
"BOMB DISPOSAL EXPERT. If you see me running, try to keep up."
 

Offline Bill S

  • Naked Science Forum King!
  • ******
  • 3631
  • Activity:
    0%
  • Thanked: 108 times
    • View Profile
Re: Does a photon self propagate due to the interactions of the electric and magnetic fields?
« Reply #19 on: 19/05/2019 16:11:27 »
Quote from: Alan
The "observer" is irrelevant since the photon, phonon or whatever has no concept of observation and the source, which may be a few billion light years away, really doesn't care what happens to the energy it radiates.

Could greater clarity be achieved if “observation” were used instead of “observer” when talking about quantum reactions?
Logged
There never was nothing.
 



  • Print
Pages: [1] 2   Go Up
« previous next »
Tags:
 

Similar topics (5)

Is there a "photon boundary"?

Started by GeezerBoard Physics, Astronomy & Cosmology

Replies: 14
Views: 7226
Last post 22/09/2010 11:40:15
by yor_on
does electric discharge goes from positive to negative or negative to positive..

Started by tareggBoard Physics, Astronomy & Cosmology

Replies: 5
Views: 9816
Last post 27/06/2018 20:34:52
by jhonmiller
Will a photon clock run at a different rate from an atomic clock under gravity?

Started by amritBoard Physics, Astronomy & Cosmology

Replies: 147
Views: 68141
Last post 07/06/2010 06:43:34
by Geezer
Two low energy photons for one high energy photon in fluorescence possible?

Started by McKayBoard Physics, Astronomy & Cosmology

Replies: 6
Views: 3185
Last post 19/05/2019 13:05:28
by alancalverd
What are Volcanic clocks and Magnetic Clocks?

Started by Karen W.Board Geology, Palaeontology & Archaeology

Replies: 3
Views: 4970
Last post 15/01/2008 05:04:06
by Bass
There was an error while thanking
Thanking...
  • SMF 2.0.15 | SMF © 2017, Simple Machines
    Privacy Policy
    SMFAds for Free Forums
  • Naked Science Forum ©

Page created in 0.257 seconds with 84 queries.

  • Podcasts
  • Articles
  • Get Naked
  • About
  • Contact us
  • Advertise
  • Privacy Policy
  • Subscribe to newsletter
  • We love feedback

Follow us

cambridge_logo_footer.png

©The Naked Scientists® 2000–2017 | The Naked Scientists® and Naked Science® are registered trademarks created by Dr Chris Smith. Information presented on this website is the opinion of the individual contributors and does not reflect the general views of the administrators, editors, moderators, sponsors, Cambridge University or the public at large.