# What is time??

Discussion in 'Science & Society' started by Shadow1, Feb 5, 2011.

1. ### Big ChillerRegistered Senior Member

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I mean as you have mentioned the young have very little experience from which to draw upon unlike an adult which is why they need to observe the world in order to gain info about the details which is the reason for experiencing time slower but not the reason how.

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3. ### hansdaValued Senior Member

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TIME plays two kinds of roles in the physical activities . First , it measures the interval or duration of time for any physical action . Second , time moves all the physical objects from past to present to future .

TIME as we know , understand and experience in our day to day life ; is one continuum . The name given to this continuum is "TIME" . A part of this continuum , which actually is 'interval of time' ; is also given the name "TIME" . This same naming for the 'whole' and its 'part' is creating all the confusions about time . For example , consider the case of "black-holes" . Time does not exist in black-holes yet black-holes exist in the present . That means :"Time(1) does not exist in black-holes ." --- this is true . " Time(2) moves the black-holes from past to present to future . " --- this is also true . So , these two time's ( time(1) and time(2) ) are of different kinds . Thats why i said there are two types of time and they can be named as 'int-time' and 'flow-time' .

Last edited: Aug 17, 2011
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5. ### hansdaValued Senior Member

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Absolute-Static FoR , at this stage is just an assumption to understand time . As per the assumtion : (1) Speed of Light with relative to the absolute-static is constant . (2) TIME is uniform with relative to the absolute-static . So , if we can find some existence which is unaffected by space and from where all the space-activities can be observed and if with relative to that existence (1) speed of light is constant and (2) time is uniform ; then we can say that , that existence is absolute-static .

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7. ### hansdaValued Senior Member

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We know relativity happens . But, do we know ; why relativity happens ? If we can know this perhaps our idea of TIME will be much more clear .

8. ### OnlyMeValued Senior Member

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Relativity, is the result of the limitations of our ability to observe change in the universe. It is that simple. We are limited by when we "see" things happen that are separated in space.

The sun light hitting our face is "now" as a part of our experience. It is the past, by approximately 8.3 light minutes from the sun's frame of reference, where it began its trip to us.

So the answer to your question is yes, we do know why relativity happens. It is because the exchange of information from one place to another has a speed limit, the speed of light.

In a sense this is an artifact of time, but as time as we perceive it is a measurement of change and our measurement and experience of change is limited by how fast information of that change can reach us.

Think of lightening and thunder.
If you are near where it occurs you see the flash and hear the thunder at what appears to be the same time. (Think of this as one frame of reference, FoR.)

If you are far from where it happens you see the flash and then some seconds latter hear the sound of the thunder. (And this as a second frame of reference.)

Each FoR experience the events in a different order. Both can understand how the other experiences the flash and sound differently. This is what relativity does for events that occur over far greater distance and a velocities that distort how events are observed even to a greater degree than the example.

Relativity is really a very simple concept, which unfortunately leads to some very complex relationships when attempting to compare and understand the order of events on large scales and at great velocities.

We cannot really at present fully explain why there is a speed limit. That must currently accept as an observed and experimentally confirmed, phenomena.

9. ### hansdaValued Senior Member

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We know due to the effect of relativity either space expands or space gets compressed . Do we know , why due to the effect of relativity either space expands or gets compressed ? This answer may tell us about the true nature of time .

10. ### OnlyMeValued Senior Member

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Why is always that \$64,000.00 question. (Which should be closer to a few million in today's dollars.)

To the best of my knowledge Einstein never gave a reason for why the presence of mass alters the shape of space. He just described the relationship and its relationship to what we experience as gravity. There have been attempts to explain how or why. Most of those have been flawed in one way or another.

Time in some ways is even more elusive than gravity. At present, as a matter of experience and the inherent limitation of perception, time is a construct of our perception of change and thus completely subject to the principle of relativity.

Would those events that result in our experience of change occurring in a linear fashion, continue in our absence? I am pretty sure a tree falling in the forest makes a sound even when it goes unheard. So yes! However, since at present it is something that happens only outside of our ability to perceive it, we can only present hypothesis and conjecture as to its fundamental nature and what an understanding transcending our present limitations might tell us.

11. ### hansdaValued Senior Member

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" Why space expands or contracts due to the effect of relativity ? "

I have a guess for the answer to this question . This guess is as follows :

Light and Sound play pivotal role in the dynamics of physical objects. Light travels through space and Sound travels through air . Medium of sound is air and medium of light is space . Sound can not exist without air ; similarly light can not exist without space . Whenever an object( mass ) travels at a speed towards the speed of sound ; behaviour of air( medium of sound ) changes . Air becomes comressible . Similarly , whenever an object(mass) travels at a speed towards the speed of light ; behaviour of space ( medium of light ) changes . Space becomes compressible . Thus high speed of the moving mass towards the speed of light , causes expansion or contraction of space ( medium of light ) .

12. ### hansdaValued Senior Member

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Is it moving mass or static mass ? If presence of any mass alters the shape of space , then path-of-light will also alter accordingly . In that case , there will be no obstacle to our vision . There will be no darkness . There will be Light and only Light everywhere .

13. ### DywyddyrPenguinaciously duckalicious.Valued Senior Member

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Wrong.

Based on a false premise. See above.

14. ### OnlyMeValued Senior Member

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While in a technical sense you are right. I believe that hansda's intent is correct in that sound does require a meter al medium. It does not propagate through empty space.

While in the early 1800s a comparison between the propagation of sound and light was logical, the knowledge of today demonstrates too many dissimilarities for any reasonable comparison.

That said I am hard pressed to understand how light can exist without "empty" space.

I believe that the comparison of sound and light is based on a false premise here and yet the basic statements hansda made are to some extent individually accurate. The propagation of sound requires a material medium such as air - a gas, water - a liquid or a solid and the propagation of light requires the emptiness or vacuum of space.

This is where the similarities seem to diverge, from my perspective. While the velocity of light in a vacuum is constant, the velocity of sound varies significantly, increasing as the density of the medium increases.

15. ### OnlyMeValued Senior Member

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I don't completely understand your meaning here.

As far as how mass affects the shape of space..? This is a question that remains unanswered. It would be difficult to even say whether it involves "moving mass or static mass", since we cannot establish that there is any known mass that involves no intrinsic motion. There is no observable preferred frame of reference we can say is at rest, so there is also nothing we can say is not in motion.

How you associate light with mass and the shape of space requires an even a more difficult "leap of faith". Light has no known "rest mass". A great deal of what we know about the universe, depends on a description of the photon that is massless. And a description of gravity that involves mass. The two light and gravity do not in that sense seem to be causally related. While space appears to be required for the propagation of light, photons (light) are emitted by atoms no empty space.

Since the path of a photon is influenced by the shape of space, I cannot say with certainty that light has no reciprocal affect on space itself. This is however, not consistent with some of the fundamental aspects of how we understand the universe to function.

16. ### hansdaValued Senior Member

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What i mean to say is that , Light travels through space . Space is the medium of light . If shape of space is not altered or distorted , light will travel in a straight line through the space . If in this straight line of space , a mass is kept and this mass alters the straight line of space to a curved line around the mass ; then light will also follow this curved line around the mass . In that case , there will be no obstacle to light . So , there will be no darkness and there will be only light throughout the space .

17. ### wellwisherBannedBanned

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5,160
If you look at energy, photons/waves, energy has one foot in C and one foot in finite reference. It occupies two time frames at the same time.

Light moves at C, which is independent of reference. This one foot is not dependent on reference. The visual output of light, which we see, is connected to the wavelength and frequency. These two parameters will change with reference, such as via the doppler shift. One foot stays at the time reference of C, while the other foot is in the finite tub of space-time adjusting to the warm and cool waters of space-time.

The uncertainty principles makes use of these two time references. If you assume one reference, their will be an uncertainty effect since this ignores the integrated time potential of two connected references. This excess time potential that is ignore will show up as uncertainty in distance. it is sort of what one would expect if you realize two references.

18. ### hansdaValued Senior Member

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We know space is required for light to propagate . In this path-of-light if a mass is placed , the change of shape of space around the mass can be judged by the path-of-light around the mass . If the mass is static or at low speed with relative to space , light gets reflected from the mass . If the mass is at high speed ( with relative to space ) to cause the effect of relativity , the light may bend over the mass and not reflect back . Thus only moving mass at high speed can change the shape of space . So any mass can not change the shape of space . Static mass ( with relative to space ) does not change the shape of space . Only moving mass ( with relative to space ) can change the shape of space .

In this case , the concept of space-time continuum is also contradicting the concept of reflection-of-light .

19. ### DywyddyrPenguinaciously duckalicious.Valued Senior Member

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19,227
Not really.

Also specious rubbish.

Wrong.

Also wrong.
Please go away and learn something. Anything.

Very probably. But this "concept of space-time continuum" is wrong.

20. ### OnlyMeValued Senior Member

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I don't think that the general intent of the above quote is true.

The recent conclusion of the GP-B experiment confirmed or reconfirmed both the geodetic and frame dragging effects. Mass both distorts space geodetically, which could be viewed as a relatively static effect and dynamically, as demonstrated by frame dragging, which involves the angular momentum of the involved mass relative to space.

Neither of these effects involve relativistic velocities. And taken together they suggest that mass, changes the shape of space both by just being there and as a function of its angular momentum. An added note is that even though frame dragging involves angular momentum, the fact that it has been confirmed to exist, suggests that any relative motion of mass in space, should produce a similar drag on space consistent with the involved motion.

How light or the path of light is affected by any of these changes in the shape of space, becomes a bit more complicated. The velocity of light is constant at least locally, where in this case locally can be defined as from the frame of reference of the involved mass, and we have no evidence that any gravitationally significant mass exists anywhere, with any locally significant relativistic velocity. Light relative to all gravitationally significant bodies, has a velocity of c and the non-relativistic velocity of the involved mass, is of no significance. While frame dragging may add an angular component to already established gravitational lensing, any similar drag on space resulting from linear motion should be insignificant as far as light is concerned.

Whether light or a photon, is absorbed by, reflected by or passes by the involved mass is determined by the initial trajectory of the photon, the composition of the object and the magnitude of its gravitational field and potentially some possible contribution from frame dragging.

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22. ### Misty155Registered Senior Member

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Time means our life is very short.

23. ### river

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17,307
wrong

your biology dictates how long you live

it has nothing to do with " time "