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Thread: Is light constant at all?

  1. #21
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    Default re: Is light constant at all?

    The god "c" pervades the universe; "he" is everywhere, and is watching YOU! ...
    He only makes his presence felt by dark matter you can't see...
    (well, ok, occasionally when shit happens....
    Last edited by BuleriaChk; 10-29-2016 at 12:07 PM.
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    Default re: Is light constant at all?

    By that argument, you could claim that all of science is a religion, Chuck. You can claim that anything is.
    In the meantime, there are proper procedures in order for the mathematics to be consistent and make sense. If you want to call those procedures "God," feel free.
    --Inter Arma Enim Silent Leges--
    “Science needs the light of free expression to flourish. It depends on the fearless questioning of authority, and the open exchange of ideas.” ― Neil deGrasse Tyson

    "When photons interact with electrons, they are interacting with the charge around a "bare" mass, and thus the interaction is electromagnetic, hence light. This light slows the photon down." - BuleriaChk

  3. #23
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    Default re: Is light constant at all?

    Quote Originally Posted by Neverfly View Post
    By that argument, you could claim that all of science is a religion, Chuck. You can claim that anything is.
    In the meantime, there are proper procedures in order for the mathematics to be consistent and make sense. If you want to call those procedures "God," feel free.
    Hi Guys,

    Long time no chat. 2 things to start this.
    1) I actually believe in God, haven't seen a church in a couple decades, although i do holler at him on most nights.

    2) Since u put this article in my name and i cant or dont know how to rename it, could u be a doll a rename it for me. "Is light constant at all" tks.

    It implies 2 things as well.
    1) Is the speed of light a constant, is it infinatley the same in or what we call universe. That is not a perfect vacume, stars planets gas and all other matter in the universe/Multiverse.

    2) Light, xray, gamma rays, radio waves, the CMB. Measured at 46 billion light years away is the distance we can see right now. Plain and simple, how do we know that this 8s not the limit we can see right now, because the photons of light xray or radio waves the cmb radiation dissipates beyond that point.

  4. #24
    Moderator Neverfly's Avatar
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    Default Re: Is light constant at all?

    Quote Originally Posted by Jason me View Post
    1) I actually believe in God, haven't seen a church in a couple decades, although i do holler at him on most nights.
    I understand exactly how you feel. I no longer am a believer in the supernatural, but I was a believer for the vast majority of my life.
    I was not much of a church goer... My personal image of God was pretty one on one. I would appeal to him, confide in him, even plead with him. To me, God was something that was always with me, by my side through it all.
    To say the 'bond was close' would be appropriate.
    When I began to let go of those beliefs and faith was one of the more painful experiences of my life.

    Quote Originally Posted by Jason me View Post
    It implies 2 things as well.
    1) Is the speed of light a constant, is it infinatley the same in or what we call universe.
    I will put this line by line:
    -The constant "c" is constant. 100%. It's value does not change.
    -Light and other forms of E.M. radiation are limited to "c" or below in velocity. You can consider "c" to be the Upper Limit or Upper Bound of velocity of anything within the Universe.
    -The constant "c" is a mathematical construct.
    -When calculating the speed of Light, it is permissible to calculate Speed of Light as "c" in your calculations if you are measuring light in a vacuum.
    -However, if calculating the Group Velocity of a beam of light moving through a medium such as air or water, you would use "v" to show the Speed of Light, not "c." You can only use "c" if light is moving at that Upper Bound.
    Now, your primary question is: Is "c" a constant throughout the entire universe?
    Given all information available, the answer appears to be "well, yeah." Without traveling to all parts of the Universe to really check, we cannot know with 100% certainty. But science is not about 'absolutes' and 'definite certainty'.
    Science is about building models of the what we see, in order to try to understand those systems. This enables us to visualize aspects we cannot see or at least, cannot easily see. By that, I mean that given a set of observations, we can infer details we might not be able to see directly.
    For example, a model of Celestial Mechanics allows us to find Extra-Solar Planets around other stars. But we cannot see those planets visually in a telescope.
    They are detected by their gravitational pull tugging the parent star creating a wobble in the stars motion. We infer the presence of the planet. Once we have a candidate, we begin using other techniques like Spectroscopy, to study chemical and elemental composition. From these models, we gather evidence to create a more detailed visual:
    The planet is very close to the sun, maybe three times the mass of Jupiter, contains ammonia, Hydrogen, sulfides, etc.

    This same process is at work for your question. Since there is no known mechanism to change the laws of physics in any observation; we can safely infer that "c" is a constant pretty much anywhere in the universe.
    But there are some details that defy that. By their very extreme nature, Black Holes may have radically different properties than anything we've observed out here and maybe "c" is also warped within one.
    The current mainstream Model of cosmology holds that the constants, such as "c," are constants everywhere or anywhere that we could travel in the universe, given sufficient time and means of transportation.
    Quote Originally Posted by Jason me View Post
    That is not a perfect vacume, stars planets gas and all other matter in the universe/Multiverse.
    The constant "c" remains the same value whether you are in a gravity well or out in the vast empty stretches of free space between galactic clusters according to current theory.
    That it is a constant even in a gravity well is how we are able to account for Relativistic Effects due to the gravity of a massive object, like the Planet Earth. The consistency of "c" means that something else must be the variable that is not "c" and that leaves "t" for Time.
    If you and I synchronized watches and I went to Jupiter and flew my ship down into the atmosphere of the gas giant, on my return we would find our clocks no longer in sync. Time would move at different rates for each of us.
    This weirdness is true, here, too and this has been calculated accurately using orbital satellites.
    Quote Originally Posted by Jason me View Post
    2) Light, xray, gamma rays, radio waves, the CMB. Measured at 46 billion light years away is the distance we can see right now. Plain and simple, how do we know that this 8s not the limit we can see right now, because the photons of light xray or radio waves the cmb radiation dissipates beyond that point.
    We can see out to about 13.6 billion light years by current estimate.
    The radius of the universe is estimated to be about 46 billion light years.
    Given that light can travel 13.6 billion light years... It is safe to say that photons do not degrade or dissipate. E.M. radiation is very consistent, with radio waves transmitted from the Voyager and Pioneer probes matching calculated intensity exactly.
    The radius of the physical universe is estimated to a much larger size than the visible universe because the Universe appears to be expanding. Additionally, it looks like it's accelerating in that expansion.
    Given almost 14 billion years for it to do so, it's expanded quite a lot so far.
    But since light is limited to no higher than "c," we can only see just under 14 billion years distant worth.
    Last edited by Neverfly; 11-05-2016 at 03:08 AM.
    --Inter Arma Enim Silent Leges--
    “Science needs the light of free expression to flourish. It depends on the fearless questioning of authority, and the open exchange of ideas.” ― Neil deGrasse Tyson

    "When photons interact with electrons, they are interacting with the charge around a "bare" mass, and thus the interaction is electromagnetic, hence light. This light slows the photon down." - BuleriaChk

  5. #25
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    Default Re: Is light constant at all?

    Testing ajsgdbxndjekejdjjd djjdjdb djjdjdn.

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    Default Re: Is light constant at all?

    Interesting was my last msg before this one deleted???

  7. #27
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    Default Re: Is light constant at all?

    There are two messages showing, one says:
    "Testing ajsgdbxndjekejdjjd djjdjdb djjdjdn. "
    The next one says:
    "Interesting was my last msg before this one deleted??? "

    I don't know, did a small connection loss lose everything you typed?
    --Inter Arma Enim Silent Leges--
    “Science needs the light of free expression to flourish. It depends on the fearless questioning of authority, and the open exchange of ideas.” ― Neil deGrasse Tyson

    "When photons interact with electrons, they are interacting with the charge around a "bare" mass, and thus the interaction is electromagnetic, hence light. This light slows the photon down." - BuleriaChk

  8. #28
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    Default Re: Is light constant at all?

    Quote Originally Posted by Jason me View Post
    Wow this is so strange. I was going to ask this same question before i made a hypothesis/theory on the multiverse. Is light a constant?
    Yes, in a vacuum it is constant.

    Quote Originally Posted by Jason me View Post
    Ok so Chk or Neverfly can u answer this pls. How come we know this universe is 13.8 billion years old??
    Basically it depends on the Hubble constant. The age of the universe is . The Hubble constant is found by finding the best line that relates the recession velocity of the galaxy as given by its red-shift to the distance as given by either Cepheid varaibles or the SN1b supernovae in that gelexy.

    Quote Originally Posted by Jason me View Post
    Lets take away the dot.
    13 800 000 000 so when does it become 13 000 000 001? I know this must be estimated but what is it estimated from?
    It´s ¨estimated¨ fronm data. It´s only an estimation as far as any linear regression is an estimation (not an estimation in the colloquial sense).

    Quote Originally Posted by Jason me View Post
    LIf light can fad and xrays ect can fad, then maybe thats the limit of what we can detect, right now.
    Not sure what you are trying to get acroos due to spelling errors. Try a good dictionary.

    Quote Originally Posted by Jason me View Post
    This will change my hypothesis/theory. Let me know what u think tks. Lol also please keep it simple u can show proof but break it down for me because my math is not great and my cosmological terms are worse. However my logical brain may be undisputed lol.
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  9. #29
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    Default Re: BuleriaChk's Ignore List

    Quote Originally Posted by Neverfly View Post
    We can make a very general estimate of the age of the universe based on how distant the most distant visible object is.
    It is more interesting how we estimate that distance, than it is how we estimate the age...
    But before delving into that, a point: EM radiation does not necessarily fade. Only muilti-amplitude EM radiation fades, light neither degrades nor fades at all.
    That is not true. Even laser light is subject to the law. So EM radiation always fades.

    Quote Originally Posted by Neverfly View Post
    How the distance is estimated is by Redshift. The more redshifted an object is, the more distant it is and this can be calculated on a mathematical scale.
    --
    // 73s; LLAP
    // KG4PAE

  10. #30
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    Default Re: BuleriaChk's Ignore List

    The constant "c" as a number without any physical context is just a number. Physics interprets "c" as a ratio - either the "speed" of light (which is constant IN A VACUUM, although you might google "vacuum" to see what physicists actually mean in terms of zero point energy), or the rate of mass creation; inside matter (depending on what you mean by that), vis a vis relativity, in which case in STR is interpreted as a light density, depending on (v/c)^2 .

    The idea that the speed of light changes in a medium is fundamental to the basic concept of refraction (a ray of light bending in a lens), D and H fields in matter (contrasted with E and B fields in vacuo), and optical spectra (change in energy through a lens at different wavelengths)

    Neverfly is either making a argument about a constant "c" as an abstract number or possibly related to STR for one particle at one wavelength only without any interactions whatever, in which c doesn't change by hypothesis (v=(v/c)c means v = v, a tautology, just like c = (c/v)v).

    The fact that the speed of light changes in a medium (e.g., a lens) is taught in every high school physics text on the planet; the fact that c changes in the presence of other photons (an energy/spin/polarization) is responsible for Einstein rings, red shift, and locally, experiments positing light against light to show photon on photon interaction ("gravity") - difficult to do because it involves tricky relations between source, path, sensor, and analysis....

    One can make a hypothesis of r = ct, where r is the radius of the universe, and t is some arbitrary "time", but it leaves a lot of stuff out of the analysis (dark matter you can't see, dark energy you can't sense) ; since one can't see the "matter" causing the effect of light in cosmological observation, such speculation is a fantasy, since proving it is a fools' errand, and unrelated to physics here on earth where c refers to "light" as electromagnetism with or without mass, depending on context.

    It is instructive to read about the Electromagnetic Field Tensor, keeping in mind the conditions on the vector 4-potential A... which allows one to specify the diagonal of the tensor as 0 - and compare THAT with the Pauli and Dirac matrices..... but first make sure you understand the relativistic unit circle in terms of and and its relation to the Lorentz transform.

    Of course, light on the earth's surface is basically light reflected from the sun (if earth were radiating light at that temperature, we wouldn't exist - which is the point of Stephen Hawking's anthropic principle - we are doomed to interpret the Universe in terms of our local physics in our roles as minor perturbations on the surface of the arth trying to play god (and especially trying to convince others to get research grants without having to make weapons) ....

    That means that philosophically, we process "information" in terms of light, which is Wheeler's point - the assumption that such information is ultimately linear (ignoring the molecules sloshing around in our brains that interpret the photon energy reaching them) is responsible for the "holographic principle" - which of course ignores the Uncertainty Principle if it applies to our imaginations as interpreters of sensory data....

    Note: the inverse square law only applies to solid angle of radiated energy (i.e., intensity), interpreted as radiation of E and B fields related by the Poynting vector in that model, it does not apply to individual (invariant) photon particles on a straight (non-interacted) geodesic in the case where there are no other photons - e.g., "observers" in addition to the one riding on the photon (that is, me, trust me).

    I.e., the photon is moving in one dimension on a straight line from the source (at the present origin between past and future - which for sure is me, but I'm not altogether sure about Thee) - to another "observer"? Of course, the observer may not send a photon directly back to you once he receives it.... if there is another observer somewhere, some when.....

    But I know I'm here - send beer and pizza if you want me to verify it...
    Last edited by BuleriaChk; 11-10-2016 at 03:57 PM.
    _______________________________________
    "Flamenco Chuck" Keyser
    The Relativistic Unit Circle 03/28/2017 07:40 AM PST
    Proof of Fermat's Last Theorem Updates 03/19/2017 8:23 PM PST
    Ignore List -The Peanut Gallery.

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