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Thread: C and time?

  1. #1
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    C and time?

    The speed of light is constant, in what ever direction, that's not disputed. Now in relativity that as I understand light speed constant C is bound up with time, eg faster you go faster time pass for an outside observer but stays the same in your field of reference. Or to put it another way the faster you go slower time passes for you with reference to an out side observer So is there a constance for time or is time a produce of light speed?

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    One of the 2 postulates of special relativity is that the speed of light in vacuum as measured by an inertial (not accelerating) observer is constant. The other postulate is that the laws of physics are the same to all inertial observers. The speed of light (c) is not "bound up with" time except in the trivial sense that c is a change in distance divided by a change in time like all speeds. The speed of light just appears in the equation for time dilation along with te velocity of an observer relative to another observer. We could say that time dilation is a product of the 2 postulates of SR and the velocity of an inertial observer.

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    Sorry, Reality Check, I'd beg to differ on 'The speed of light (c) is not "bound up with" time except in the trivial sense that c is a change in distance divided by a change in time like all speeds'. c pops up in the standard forms of the invariant spacetime interval as the scaling factor that relates spatial to temporal intervals. Generally S = +/- ( c^2 (t1-t0)^2 - (x1-x0)^2 - (y1-y0)^2 - (z1-z0)^2 ). c also pops up in the inequalities that define the causal structure of GR and other theories. So in that sense it is fundamental to our definition of how time is arranged.

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    I'm no graduate, but its funny to see such arguments based on mathematics and theories, when the only true answer is,, no one really knows. Not long ago earth was the center of the universe, Earth was flat. The pope warned physicist Stephen Hawkings "NOT " to probe for answers near the singularity, or big bang, cause thats the hand of God. I think Time is irrelevant and only has meaning to us because we are such primitive life forms, so limited n our knowledge. I don't think time has anything at all to do with the speed of light except as a measuring tool for a limited species. The discovery of Higgs Bosen just about blows the whole "time/space" theory right out the window. We now know it can instantaneously appear where ever it wants, with no limit of speed or time. Its instantaneous. Light is obviously NOT the fastest thing we know of, if we can simply admit that what we call gravity is obviously fast enough to catch and stop it. I suspect light proves to be one of the slowest forms of energy in the not too distant future. We only think its fast because it is all we have learned to detect and interact with. Im sure it will be considered a waste product of much greater forces in the not so distant future. like the smoke from an in-efficient fire.

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    That is correct. The speed of light c does appear in SR and GR.
    However "C is bound up with time" in the OP seems to be about time itself, i.e. the time coordinate in Minkowski spacetime, not time intervals.

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    uh-oh. Time coordinate? Don't knock yourself out, just point in the right direction. Thanks.

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    Quote Originally Posted by DanielAShinerock View Post
    I'm no graduate, but its funny to see such arguments based on mathematics and theories, when the only true answer is,, no one really knows.
    You mean stop doing science? Sorry, but on a science forum with a lot of amateur and professional scientists posting on it that is a stance that is unlikely to gain many fans.

    Quote Originally Posted by DanielAShinerock View Post
    Not long ago earth was the center of the universe, Earth was flat.
    And it was arguments based on theories that overturned these idea. Because the theories could be tested.

    Quote Originally Posted by DanielAShinerock View Post
    The discovery of Higgs Bosen just about blows the whole "time/space" theory right out the window. We now know it can instantaneously appear where ever it wants, with no limit of speed or time. Its instantaneous.
    Not true. Unless you think that water also throws the whole time/space thing out of the window because when you are on the ocean, wherever you look, there is water. No limits on speed or time, it is always there. The Higgs Boson is a manifestation of a background field. I have no idea what your claims about its behaviour are based on.

    Quote Originally Posted by DanielAShinerock View Post
    Light is obviously NOT the fastest thing we know of, if we can simply admit that what we call gravity is obviously fast enough to catch and stop it.
    GR describes gravity as warped spacetime. It has no need to chase after light to affect it. Plus more generally in field theories things interact via fields, which are local. The image of a body shooting out gravitons that have to catch photons is not accurate.

    Edit to add: This is a sidetrack to the main topic of this thread, though. I'm hoping Reality Check and my answers will spawn some more questions/thoughts from Speach so lets give space for that to happen rather than derail into something else.
    Last edited by Shaula; 2017-Apr-05 at 06:28 AM.

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    I'm confused, Time isn't anything, there is no waves of time or particals of it, so it's a product of light. Gravity can't go faster than light, or else the event that LIGO detected would have past by along long time ago, as for this by DanielAShinerock The discovery of Higgs Bosen just about blows the whole "time/space" theory right out the window. We now know it can instantaneously appear where ever it wants, with no limit of speed or time. It can't just appear that would mean making something out of nothing. Which again would mean that god is real and that is clearly a preposterous claim. (and it's spelt Boson)
    But to get back to time what is it? Is an affection to measure going round the sun, no. But it must be something or the light from a star galaxy etc. would be here at the same instance it left.

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    Quote Originally Posted by speach View Post
    But to get back to time what is it?
    It is a dimension; in other words, one of the coordinates you need to specify an event. For example, if you are meeting someone you need to specify the place (3 dimensions) and the time (the 4th).

    The speed of light can be used as a "scaling factor" between the space and time dimensions, but I don't think there is any more fundamental connection.

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    Quote Originally Posted by speach View Post
    I'm confused, Time isn't anything, there is no waves of time or particals of it, so it's a product of light....
    As Strange says it is a dimension, like the spatial ones. It has a set of relationships that relate it to spatial dimensions and together they have a causal structure related to the speed of light. What do you feel is left out of this description of it?

    But it must be something or the light from a star galaxy etc. would be here at the same instance it left.
    Only in the same way space 'must be something' otherwise the light from the distant galaxy would be here at the same instance it left because here would also be there.

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    The stuff of the universe is what it is and does what it does, which includes changing. As I see it, time is one of those concepts by which we evaluate the changes, and I cannot find a way to define it literally without getting into circular reasoning.

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    Quote Originally Posted by DanielAShinerock View Post
    I'm no graduate, ..
    Lots of irrelevant musing. What you get wrong:
    1. The "only true answer" in science is that we do really know based on the evidence that we have.
      We know more than we knew yesterday. We will know more in the future.
    2. The Higgs boson was found in spacetime and so confirms spacetime !
      The Large Hadron Collider exists at a point on the surface of the Earth (space) and has been running for years (time).
      QM includes space and time and was used to predict that Higgs boson.
    3. The Higgs boson does not "instantaneously appear where ever it wants".
    4. The Higgs boson does not have "no limit of speed or time".
    5. The recent 2 detections of gravitational waves show that the speed of gravity is the speed of light.

    You may also want to read Myth of the flat Earth. The Earth was generally accepted as spherical by scholars since about 330 BC when Aristotle provided evidence for the spherical shape of the Earth on empirical grounds.
    Spherical Earth
    The earliest reliably documented mention of the spherical Earth concept dates from around the 6th century BC when it appeared in ancient Greek philosophy[1][2] but remained a matter of speculation until the 3rd century BC, when Hellenistic astronomy established the spherical shape of the Earth as a physical given. The paradigm was gradually adopted throughout the Old World during Late Antiquity and the Middle Ages.[3][4][5][6] A practical demonstration of Earth's sphericity was achieved by Ferdinand Magellan and Juan Sebastián Elcano's expedition's circumnavigation (1519−1522).[7]
    Last edited by Reality Check; 2017-Apr-06 at 01:07 AM.

  13. #13
    Quote Originally Posted by Hornblower View Post
    The stuff of the universe is what it is and does what it does, which includes changing. As I see it, time is one of those concepts by which we evaluate the changes, and I cannot find a way to define it literally without getting into circular reasoning.
    Nothing wrong with circular reason per se, providing the initial assumption(s) are valid. If they are, the circular nature of the reasoning potentially provides a proof for the reasoning leading back to the valid assumptions started with. It's a loop, but loops are necessary things. Personally, I go one step further in regarding them "good" things, provided you are aware of the loop.
    Last edited by Canis Lupus; 2017-Apr-08 at 09:17 PM.

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    Quote Originally Posted by Canis Lupus View Post
    Nothing wrong with circular reason per se, providing the initial assumption(s) are valid. If they are, the circular nature of the reasoning potentially provides a proof for the reasoning leading back to the valid assumptions started with. It's a loop, but loops are necessary things. Personally, I go one step further in regarding them "good" things, provided you are aware of the loop.
    I am having a hard time making sense of that post. Can you illustrate your line of thought specifically as it would apply to time?

  15. #15
    Quote Originally Posted by Hornblower View Post
    I am having a hard time making sense of that post. Can you illustrate your line of thought specifically as it would apply to time?
    No, sorry. I decline on two grounds.

    1. I don't understand how it works in relation to time.
    2. Therefore, to provide further explanation and examination of the idea in some depth would effectively hijack this thread.

    I made the observation with the primary purpose that you would not be discouraged in providing a definition to the OP's question based on your reluctance to engage in circular reasoning. It was a general assertion in response to your general assertion. At that level, it seems to interfere little with the thread's purpose.

    I've found reading the answers interesting. I wanted it explored in some depth, as much for myself as the OP.

    That stated, I have no doubt this will come up again. In preparing some diagrams which effectively show this, I have realised it would be advantageous for members here to eventually suggest improvements. In doing so they would assist in refining these diagrams. If that occurred I would be extremely grateful.

    As far as I am concerned, please feel more than welcome to return to the point of the thread, and kindly overlook my intervention for the purposes of encouragement.
    Last edited by Canis Lupus; 2017-Apr-09 at 12:36 AM.

  16. #16
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    Quote Originally Posted by speach View Post
    I'm confused, Time isn't anything, there is no waves of time or particals of it, so it's a product of light. Gravity can't go faster than light, or else the event that LIGO detected would have past by along long time ago, as for this by DanielAShinerock The discovery of Higgs Bosen just about blows the whole "time/space" theory right out the window. We now know it can instantaneously appear where ever it wants, with no limit of speed or time. It can't just appear that would mean making something out of nothing. Which again would mean that god is real and that is clearly a preposterous claim. (and it's spelt Boson)
    But to get back to time what is it? Is an affection to measure going round the sun, no. But it must be something or the light from a star galaxy etc. would be here at the same instance it left.
    It is very clear to me that speach is asking what time is, so my mention of the challenge of defining it literally is very much on topic. My take on it is that time is analogous to the point, line and plane as presented in my high school version of geometry. The authors presented them as undefined terms which are conceptually self-evident. They went on to define space as the set of all points for the purpose of building the logical system in which the fundamental terms and the postulates which were also taken as self-evident formed a foundation.

    Suppose I define time as the dimension by which we analyze how fast or slow changes are. How do we define fast and slow without referring to time?

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    Quote Originally Posted by Hornblower View Post
    It is very clear to me that speach is asking what time is, so my mention of the challenge of defining it literally is very much on topic. My take on it is that time is analogous to the point, line and plane as presented in my high school version of geometry. The authors presented them as undefined terms which are conceptually self-evident. They went on to define space as the set of all points for the purpose of building the logical system in which the fundamental terms and the postulates which were also taken as self-evident formed a foundation.

    Suppose I define time as the dimension by which we analyze how fast or slow changes are. How do we define fast and slow without referring to time?
    Yes that is what I'm asking. In away it's like light in that it has no negative length/dimension. I can see that it's a measurement but only in the positive. So to my mind light and time are for ever entwined, Space time continuum?

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    Quote Originally Posted by DanielAShinerock View Post
    I'm no graduate, but its funny to see such arguments based on mathematics and theories, when the only true answer is,, no one really knows. Not long ago earth was the center of the universe, Earth was flat. The pope warned physicist Stephen Hawkings "NOT " to probe for answers near the singularity, or big bang, cause thats the hand of God. I think Time is irrelevant and only has meaning to us because we are such primitive life forms, so limited n our knowledge.
    Eratosthenes provided a very decent estimation of the circumference of the Earth over 200 years before the birth of Christ, because the Ancient Greeks were very well aware that the Earth was a sphere - it's simply not correct that "everyone thought the Earth was flat". Notwithstanding that point, we have emerged from such ignorance because of science. We are not close to knowing it all, but we are a long way closer than we would be without it. It always strikes me as fascinating that people who rail against science tend to do so on their computer... if they wanted to be true to their arguments, they should probably provide them on parchment with a goose feather quill, or in ochre on a cave wall. But I digress.

    And what do you suggest is an acceptable alternative? Your post seems to suggest that we shouldn't bother trying to find things out, or else we should placidly accept "the Truth" from some appointed (or anointed) authority. Frankly, neither approach is particularly palatable.

    Science (in the language of mathematics) has provided an indication that space and time are inextricably woven together, and the speed of light is 'the mediator' between them. We know that cannot be the complete answer because Relativity & QM don't mesh - but I'm far more comfortable that we are at the (incomplete) point we are than if we just hadn't even bothered to ask the questions at all.
    Last edited by AGN Fuel; 2017-Apr-10 at 03:40 AM.

  19. #19
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    In special relativity, time is simple.

    Imagine a right angle triangle with sides X, Y, and S. Let S be the hypotenuse, X be the space coordinate, and Y be the time coordinate. We know that S2 = X2 + Y2 . If you measure the separation of two events, then S is constant. For light, S=0. Here I've used Y=ict, where c is the speed of light and t is measured time(called proper time). I put the imaginary number in there for fun. All it does is avoid a minus sign.

    Done.

    The first event could be lightning striking a tree, and the second event could be you seeing and hearing this from 2 miles away. For the light which travels from the tree to your eye, S=0. It doesn't matter who measures it, where they are, and how fast they're moving. S=0.

    Now for the sound, it will take a few seconds to travel to your ears. So we'll have t=10 seconds and x=3200 meters. Now it does matter who measures it, and how fast they're going. We will all get the same S, but we won't agree on the mix of X and Y.

    It's not so crazy to treat time on an equal footing with space.

    Unfortunately, when you try to go beyond special relativity, things aren't so neat and easy to visualize.
    Last edited by ShinAce; 2017-Apr-10 at 06:38 AM.

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    Quote Originally Posted by speach View Post
    Yes that is what I'm asking. In away it's like light in that it has no negative length/dimension.
    No more or less than do the spatial dimensions. Of course, you can choose an origin such that there are negative distances but the same is true of time (see "years BC", for example).

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    Light -- and other massless particles, if there are any -- has a
    simpler relationship to time than anything else has. You can
    say how far a massless particle has travelled just from how
    much time has gone by. Everything else has all sorts of other
    complicating factors. That's the only way in which I agree that
    there is a likeness or similarity between time and light.

    -- Jeff, in Minneapolis
    http://www.FreeMars.org/jeff/

    "I find astronomy very interesting, but I wouldn't if I thought we
    were just going to sit here and look." -- "Van Rijn"

    "The other planets? Well, they just happen to be there, but the
    point of rockets is to explore them!" -- Kai Yeves

  22. #22
    Quote Originally Posted by Jeff Root View Post
    Light -- and other massless particles, if there are any -- has a
    simpler relationship to time than anything else has. You can
    say how far a massless particle has travelled just from how
    much time has gone by. Everything else has all sorts of other
    complicating factors. That's the only way in which I agree that
    there is a likeness or similarity between time and light.

    -- Jeff, in Minneapolis
    Quantum loops (entanglement) suggest there are massless particles which have nothing to do with time.

    Opens the door a little to such ideas as the single electron theory proposed originally by John Wheeler to Richard Feynman in 1940. Potentially, a looped electron might travel faster than light i.e. instantaneously anywhere it need be. Un-entanglement, as occurs during nuclear fusion IMO, may create a mass or a massless particle(s) travelling at the speed of light as a byproduct before or at the moment of further entanglement ("re-entanglement") into the higher element.
    Last edited by Canis Lupus; 2017-Apr-13 at 11:59 AM.

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