Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: ianhutt on 11/09/2008 10:08:05
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Ian Hutt asked the Naked Scientists:
From our perception time always flows at a constant rate irrespective of our
speed.
Is it possible to ascertain whether time has remained constant throughout the life of the universe or if it is possible that it has varied since it was created by the Big Bang.
Thank you
What do you think?
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I think you have to think carefully about what you mean by time. In human terms we may perceive time to pass slowly or quickly; it may be something to do with how many operations our brains are carrying out in each second. Our perception is related to us and not to time itself. We can define time as how long it takes the earth to rotate on its axis (a traditional way) which is good for our everyday activities.
The second is defined now in relation to the metre length and the constancy of the velocity of light. If everything scales in the same way you can postulate that all dimensions started at zero and that space-time grew simultaneously. This is one of several ideas but really, nobody knows for sure. There is thought to be quantisation of time with a minimum unit of Planck time which is about 5.4x10^-44 sec.
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Everything that exists within the universe exists within it's own space-time frame, which is itself affected by everything else in the universe. For example, a photon that has existed since the very early stages of the BB should have experienced no time passing due to relativistic time-dilation, whilst us folks here on Earth see it running at nearly it's full rate (We're in a gravity well so we experience some time-dilation but the amount is very small).
In summary: the rate of time depends upon the conditions of the observer. However, it can only be slowed down but never increased or reversed.