Questions about light..

Discussion in 'Physics & Math' started by Magical Realist, May 25, 2023.

  1. Magical Realist Valued Senior Member

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    What is the medium thru which light waves are transmitted across space? Can we reasonably distinguish light from the information it is carrying? What would light that doesn't carry information be like? Is there any calculation of the amount of information that a light wave can carry? Does each wave of light correspond to one or many photons? Is the information carried by a light wave the same or different from the information carried by a photon? Where does the information light is carrying go when a light wave is absorbed into matter?
     
    Last edited: May 25, 2023
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  3. DaveC426913 Valued Senior Member

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    Light has no medium of transmission. It is a self-propagating interaction of disturbances between and electric field and a magnetic field. i.e. electromagnetic radiation.

    What constitutes information is in the eye of the beholder.

    No. See above.

    They are one and the same thing.

    In principle, one could roll back the interaction and recover the components, so it's there, just converted.
     
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  5. Magical Realist Valued Senior Member

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    Does that mean information is not objectively "there" like matter is? That the existence of information outside of an interpreting mind is in question?
     
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  7. DaveC426913 Valued Senior Member

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    Yes.

    Consider Fermi's Paradox: "If, by probability alone, the universe ought to be supposedly full of alien life, where is it?"

    We can consider the absence of detection of life as useful information to make deductions (albeit flimsy ones) about the density of life in the universe.

    So, even an absence of data can be interpreted as useful information. But it requires an interpreting mind to examine and draw conclusions.
     
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  8. DaveC426913 Valued Senior Member

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    Wiki has a neat little primer (though definitions and usages are myriad):

    "Information is an abstract concept that refers to that which has the power to inform. At the most fundamental level, information pertains to the interpretation (perhaps formally) of that which may be sensed, or their abstractions. Any natural process that is not completely random and any observable pattern in any medium can be said to convey some amount of information. Whereas digital signals and other data use discrete signs to convey information, other phenomena and artefacts such as analogue signals, poems, pictures, music or other sounds, and currents convey information in a more continuous form. Information is not knowledge itself, but the meaning that may be derived from a representation through interpretation."
    https://en.wikipedia.org/wiki/Information
     
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  9. Guestfornow Registered Member

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    There we have it. In order to interpret "raw" information it has to be given a context. The context is an arbitrary choice, but in human science generally the context already has meaning: a binary string can be interpreted in many different ways.

    Light already has a context, for humans, because it's visual information. You have a brain with a visual cortex that has evolved to interpret patterns in the "input data".

    Data is another arbitrary interpretation; information interpreted as data is still information.
     
  10. DaveC426913 Valued Senior Member

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    Light is the medium; it does not in-and-of-itself provide context.
     
  11. Guestfornow Registered Member

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    A binary string stored in a memory is the medium, it does not in-and-of-itself provide context.
    If I write a program that interprets this string as a number, that is a context. That interprets the string, right?
     
  12. DaveC426913 Valued Senior Member

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    Correct.
     
  13. DaveC426913 Valued Senior Member

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    Notice that this requires a mind, performing an interpretation, deciding what aspects have meaning and what aspects do not.
     
    Last edited: May 25, 2023
  14. Guestfornow Registered Member

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    Notice that, in day to day experience, humans and other animals interpret their surroundings and decide what is important or relevant and what isn't.
     
  15. DaveC426913 Valued Senior Member

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    Isn't that what I just said?
     
  16. Guestfornow Registered Member

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    I'm not sure.
     
  17. Seattle Valued Senior Member

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    It would be interesting to have a forum where the first response to any question ran through something like ChatGPT.

    If that was incorrect or if there were still any questions the human forum members would jump in.

    In this case (and in most cases) there would just be one response needed.

    "
    Light waves are transmitted across space through a medium called the electromagnetic field. In a vacuum, which is a near-empty space, light waves can propagate without the need for a physical medium. This is because light is composed of self-propagating electric and magnetic fields that interact with each other, creating electromagnetic waves.

    Distinguishing light from the information it carries can sometimes be challenging. The information contained in light is typically extracted through its interaction with a detecting system, such as our eyes or specialized instruments. We interpret the properties of light, such as its intensity, color, and polarization, to extract information about the objects or phenomena that emitted or interacted with the light.

    Light that doesn't carry any discernible information would essentially be random or uniform in its properties. It would lack any distinguishable patterns or variations that could be used to convey meaningful information.

    The amount of information that a light wave can carry depends on various factors, including its bandwidth, intensity, modulation scheme, and encoding techniques. Information capacity is often quantified using concepts like data rate (bits per second) or channel capacity (maximum achievable data rate).

    Each wave of light can correspond to many photons. In classical physics, light is described as an electromagnetic wave, and the energy it carries is distributed continuously throughout the wave. However, in quantum physics, light is also considered to be made up of discrete particles called photons. The relationship between light waves and photons is described by wave-particle duality.

    The information carried by a light wave and a photon can be considered the same in some cases. For example, in communication systems using photons, the information encoded in the light wave is typically encoded in individual photons. However, in other scenarios, such as spectroscopy or quantum information processing, the distinction between the information carried by a light wave and a single photon becomes more significant.

    When a light wave is absorbed into matter, its energy is transferred to the absorbing material. The energy can cause various effects depending on the specific interaction. For example, it may be converted into heat, chemical reactions, or the excitation of electrons in atoms or molecules. The information carried by the light wave can be used to induce changes or provide input to the receiving system, leading to different physical or chemical processes."
     
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  18. Magical Realist Valued Senior Member

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    Here's a conundrum. Suppose two people are standing together. One can see and the other is blind. Both have an image on a screen flashed to them. For the one who can see, the light carries information about the image. For the blind one there is no information at all. Does the light carry information or not?
     
  19. Seattle Valued Senior Member

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    There is information for the sighted person to derive and the blind person can't do that of course.

    I may be your neighbor and I need help so, at night, I see that you are outside and I blink a flashlight in your direction. All the light is doing is going off and on. It's up to you to determine if there is an information to be derived.

    Is this really a conundrum?

    Please Register or Log in to view the hidden image!

     
    Last edited: May 26, 2023
  20. Magical Realist Valued Senior Member

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    So you are saying the information is there in the light and is objectively real? That's not what Dave was saying. He asserted that information only exists in the mind of an interpreter.
     
    Last edited: May 26, 2023
  21. Seattle Valued Senior Member

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    That's not what I said at all.
     
  22. Magical Realist Valued Senior Member

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    Ok then...moving on.
     
  23. Michael 345 New year. PRESENT is 72 years oldl Valued Senior Member

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