Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Brian Martell on 27/11/2011 14:01:02
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Brian Martell asked the Naked Scientists:
Hi,
I was wondering the other day,
If Einstein declared that when an observer is near very dense matter object such as a neutron star or black hole, that time will actually appear to slow down for the observer near that object.
Makes sense to me.
Now, if you do the opposite, by going to an area of the Universe where there is not any matter, like the voids in between the Galaxies. Would not time be running there at a faster rate than if you were in a galaxy on a planet.
What I'm asking is this:
Could the real "rate of time" for clocks be the time measured in the, "void areas between galaxies", and the time that we observe today be changed or slowed down by the gravity of our own Milky Way galaxy and it's component stars and planets?
Would that give an explanation as to why the Universe's expansion rate is increasing because the voids between the galaxies are getting older faster than the galaxies themselves?
There would be no need for Dark Matter or dark energy components.
Just a thought...
What do you think?
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This question needs a bit of logical analysis because it is based on a bit of poor thinking
Firstly in order to be aware of time passing it is essential to have some sort of "clock" an empty space by definition contains no material and a clock can not be made out of nothing. This implies that in truly empty space the passage of time cannot be measured.
Secondly for anything to "age" it must change in some measurable way as time passes both empty space and stable subatomic particles are therefore ageless. Note this does NOT imply that a clock cannot be made out of assemblages of stable particles using other oscillatory properties that they have. Individual unstable particles decay randomly so no passage of time can be inferred from the decay of an individual particle. Large numbers of similar unstable particles and atoms can measure time by the statistical process of their half lives. Both the rate of decay and the total number of particles or products could be used but a knowledge of the situation at an earlier time is essential and only the passage of time measured.
Thirdly with all these clock problems the clock where the observer is, is always working normally and counting the same passage of time as a similar clock elsewhere in a different environment for example moving at velocities significant with the velocity of light or in an area with a different gravitational potential (near to a dense gravitating body). Note good clocks must work uniformly in and during any stresses in moving to a different environment.
It is only when one observes one clock in one environment from a clock in a different environment either moving or gravitational or possibly compares the passage of time indicated by a pair of clocks that have been subjected to different journeys and then return to the same place that any time difference could be observed.
This means that the possible explanation of increased expansion rate that you are suggesting could not be valid because it is based on first principles that are in error.
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As Soulsurfer writes.
With one addendum. There is 'gravity' existing, and theoretically you can define any patch of gravity as giving you a different 'clock rate' relative your own 'local clock'. But it also has to do with how you define times arrow. As something needing 'change' to exist, or as something 'existing' in itself.
Einstein's definitions treats 'time' as a dimension, same as the other three (length, width and height). Defined that way 'times arrow' should exist everywhere as I see it. But if you define it through 'change' itself, then it belongs to the exact 'particles, fields' etc, and their changing, as measured by you.
Which one is right? Entropy seems to prefer the later interpretation as I understands it. The theory of relativity prefers the first as it involves gravity as a measure of changing a clock rate relative your local definition, again as I see it.
Locality here means that you send a light signal from a source that also will be your 'clock' measuring a 'time rate'. As that light signal bounce from another mirror, at a by you defined distance, to return to your original 'source', now becoming your detector it will give you a 'speed', defined purely by that very local clock embedded in your 'source/detector'. And that's a very lovely way of defining 'locality', and 'c', that Einstein used. This type of measurement will always give you a 'constant for lights speed in a vacuum, whether it is done in a accelerating spaceship, or at the same ship moving uniformly.
Introducing 'gravity' lights speed in a vacuum, divided in its smallest, meaningful, 'splits', is defined as making one Plank length in one Planck time. That, combined with using radiation as your 'ideal clock', will give you a 'frame of reference' (using clocks as the definition) relative all other 'ideal clocks', measured as one Plank length (ideally, not practically).
So gravity will give you a 'time dilation', which also means, if we assume that this is right, that all parts of you constantly is 'time dilated' relative each other, if taken to its extreme. But then you also have HUP (Heisenbergs Uncertainty Principle) stepping in on a greater scale, around atom size, or maybe even bigger?