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Serious Question on Clocks & Time

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Comments

  • Registered Users, Registered Users 2 Posts: 3,457 ✭✭✭Morbert


    dadvocate wrote: »
    Could that be due to the want of some physical constant that is not known thus far?

    Instead of thinking of the spring that drives a mechanical clock, consider the battery that powers the digital watch.

    Let's say the mass of the battery is 2 grammes and it is rated at 200 mA/H.

    If the watch is accelerated to 0.5 c, a stationary observer can calculate a new apparent mass, according to his own FoR, which would be 2 grammes plus some value that appears due to momentum, right?

    What I'm wondering is, from that same FoR, would the observer have calculate a new value for the rating of that batterry?

    Is the 200 mA/H modified in any way due to momentum?

    It seems to me that the battery would 'appear' to last longer in a watch travelling at high speed.

    How is potential energy in a battery, or a wound up spring for that matter, effected by momentum, as a result of velocity, from the point of view of a stationary observer?

    The duration of the battery is lengthened as defined by the Lorentz transformations. This is not due to an increase in mass or a hidden constant, however. It is instead due to the Lorentz invariance of the laws of physics. So any system, independent of mechanism or property, will be affected by time dilation by the same amount.


  • Banned (with Prison Access) Posts: 95 ✭✭dadvocate


    Morbert wrote: »
    The duration of the battery is lengthened as defined by the Lorentz transformations. This is not due to an increase in mass or a hidden constant, however. It is instead due to the Lorentz invariance of the laws of physics. So any system, independent of mechanism or property, will be affected by time dilation by the same amount.

    Which seems to imply that the current consumption of the watch is Lorentz transformable; that a travelling electronic device consumes less current?

    I hope you don't mind me picking your brain this way but I find this whole thing intriguing.

    Could we speak a little about the notion of a straight line?

    I suppose 'geodesic' is probably a more apt term.

    If I accelerate along a line on the earth then at a certain speed, escape velocity, I will no longer be confined to the earth's surface. If I continue to accelerate, then I could escape the gravitational pull of the earth altogether.

    Let us suppose that I am travelling along a line of latitude, say the equator. While I am bound to earth, although I am travelling in what 'feels' like a straight line, I am in fact travelling along a curve and ultimately, I am simply completing a circle.

    Until I achieve escape velocity at which point the earth's gravity reduces its effect on the curve along which I travel.

    The earth itself is effectively travelling along a geodesic path too and the curvature of its path is due to the sun's gravity. It is as if the surface of the sun is 93 million miles from its centre and the earth is rolling along describing a kind of imaginary equator.

    Now, when I am travelling at a speed that prevents gravity from affecting the curvature of my path then, I think, I would be travelling along a geodesic path that represents the curvature of space and this would 'feel' like a straight line too.

    And the faster I travel, the flatter the curvature of my path through space becomes.

    Could I think of the speed of light as being the escape velocity with regard to the curvature of space and thence, in the same way as gravity is overcome as I accelerate along the earth's surface, the effect of spacetime is overcome as the curvature of my path becomes 'flatter' than the curvature of space?

    In this way I can imagine how a mass travelling at high velocity can become somewhat 'disconnected' from spacetime.

    Do you see where I'm coming from with this? Am I barking up the right tree?

    And, it occurs to me, any further increase in velocity is manifest as further flattening of the curvature which further disconnects the travelling mass from the qualities of existence that come about from the physical characteristics imbued by spacetime.


  • Registered Users, Registered Users 2 Posts: 3,457 ✭✭✭Morbert


    dadvocate wrote: »
    Which seems to imply that the current consumption of the watch is Lorentz transformable; that a travelling electronic device consumes less current?

    I hope you don't mind me picking your brain this way but I find this whole thing intriguing.

    Could we speak a little about the notion of a straight line?

    I suppose 'geodesic' is probably a more apt term.

    If I accelerate along a line on the earth then at a certain speed, escape velocity, I will no longer be confined to the earth's surface. If I continue to accelerate, then I could escape the gravitational pull of the earth altogether.

    Let us suppose that I am travelling along a line of latitude, say the equator. While I am bound to earth, although I am travelling in what 'feels' like a straight line, I am in fact travelling along a curve and ultimately, I am simply completing a circle.

    Until I achieve escape velocity at which point the earth's gravity reduces its effect on the curve along which I travel.

    The earth itself is effectively travelling along a geodesic path too and the curvature of its path is due to the sun's gravity. It is as if the surface of the sun is 93 million miles from its centre and the earth is rolling along describing a kind of imaginary equator.

    Now, when I am travelling at a speed that prevents gravity from affecting the curvature of my path then, I think, I would be travelling along a geodesic path that represents the curvature of space and this would 'feel' like a straight line too.

    And the faster I travel, the flatter the curvature of my path through space becomes.

    Could I think of the speed of light as being the escape velocity with regard to the curvature of space and thence, in the same way as gravity is overcome as I accelerate along the earth's surface, the effect of spacetime is overcome as the curvature of my path becomes 'flatter' than the curvature of space?

    In this way I can imagine how a mass travelling at high velocity can become somewhat 'disconnected' from spacetime.

    Do you see where I'm coming from with this? Am I barking up the right tree?

    And, it occurs to me, any further increase in velocity is manifest as further flattening of the curvature which further disconnects the travelling mass from the qualities of existence that come about from the physical characteristics imbued by spacetime.

    Light can't escape the curvature of spacetime. In fact, light beams trace out the "null cone structure" of spacetime, and the null cone structure represents the curvature of spacetime. This is what allows things like gravity lenses to exist ( https://en.wikipedia.org/wiki/Gravitational_lens ). In fact you can eve get photons travelling in an orbit. ( http://en.wikipedia.org/wiki/Photon_sphere ).


  • Registered Users, Registered Users 2 Posts: 1,169 ✭✭✭dlouth15


    dadvocate wrote: »
    In this way I can imagine how a mass travelling at high velocity can become somewhat 'disconnected' from spacetime.

    Do you see where I'm coming from with this? Am I barking up the right tree?

    And, it occurs to me, any further increase in velocity is manifest as further flattening of the curvature which further disconnects the travelling mass from the qualities of existence that come about from the physical characteristics imbued by spacetime.
    You say earlier:
    Now, when I am travelling at a speed that prevents gravity from affecting the curvature of my path then, I think, I would be travelling along a geodesic path that represents the curvature of space and this would 'feel' like a straight line too.

    And the faster I travel, the flatter the curvature of my path through space becomes.

    Reading over your post, I think where you're going wrong is mixing up space and spacetime. Consider two objects making their way between points A and B in space under gravity. Both leave point A at the same time. The second is traveling faster than the first. Since they both leave at the same time a single point (or event) in spacetime can be used. But they don't arrive at point B at the same time so two events are necessary for the ends of the journeys.

    The two objects' geodesics are fully determined by the curvature of spacetime but the apparent paths through space can be radically different.

    If you stand on the earth and throw a ball vertically upwards it will land back in your hand at the same point later. There's a geodesic fully based on the curvature of spacetime that connects the two spacetime events. If you through the ball faster there's another geodesic that connects the two events. They are the same points in space but different events in spacetime. Spacetime is curved in exactly the same way for both throwings but the geodesic through spacetime is different and hence we get a different path for the ball though space and time. It goes further up in space and arrives back at your hand some time later.

    There are also geodesics that take the ball to an infinite distance in space away from your hand and never return. The minimum initial velocity to achieve this, then, would be the escape velocity.

    But the curvature of spacetime is the same in all cases. The geodesics are simply going through different regions of it.

    I would be interested in Morbert's opinion on this answer. I'm just trying to get my head around this stuff at the moment.


  • Registered Users, Registered Users 2 Posts: 491 ✭✭Justice


    if ye dont mind i'm jumping in to the end of this conversation.

    Atomic clocks esentially measure the emitted energy output from the an excited cesium atom (by excited i mean energy is added to the atom, not sure if its electric or magnetic).

    The wavelengh of the emitted light is constant for all atoms of cesium (regardless of where in the universe or when its checked).
    A second is defined as a fixed number of wavelengts of energy emitted by the cesium atom.
    Since the speed of this energy release is the speed of light and is constant everywhere in the universe and the number of wavelenghs is also constant the exact lenght of a second can be determeined anywhere in the universe.

    relativity shows us that 2 different clocks in 2 different relativistic situations calculate the lenght of a second DIFFERENTLY from eachother, but that is the effect of relativity, not time. if the same two clocks are in the same relativistic situation they will calculate the same time for one second.

    i think relativity means that their is no such thing as a "universal" time. that is not the same thing as saying their is no such thing as a "universal method of calculating time". so your two clocks (mechanical or electrical) travewlling at two different speeds will not calculate the same time value as eachother, but they are both still right, but only for the relative situation each is in.

    obviously the choice of 1 second being the lenght of time it is, is based on the sun travelling around the earth. however scientists calculated the number of wavelengs cesium emmitted in the old standard "1 second". this number was then used to make a new definition of time.

    in fact distance "the meter" is now also defined in similiar terms. a meter is the length of distance light will travel in "x" number of wavelengts of sesium.

    i happened to watch a tv program last night with all this info.
    Precision: the measure of all things


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