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ryan albery
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Are there any theories or thoughts that view spacetime as 'having' a coefficient of thermal expansion... analogous to the CTE of water? An inflection with density in regards to temperature?
ryan albery said:Are there any theories or thoughts that view spacetime as 'having' a coefficient of thermal expansion... analogous to the CTE of water? An inflection with density in regards to temperature?
Vanadium 50 said:No. How would you measure such a thing?
I can understand how 'space' itself doesn't have any ponderable properties, but spacetime, I think even Einstein came to think of 'it' as a thing.
In SR, if you move along at a constant velocity, your time ticks off at a steady pace. Not so in GR...Proper time along a path [called a worldline] is an observable but it is not 'ticks at a steady pace'...
The proper time, tau, along spacetime trajectories cannot be used as an independent variable either, as tau is a complicated non-local function of the gravitational field itself. Therefore, properly speaking, GR does not admit a description as a system evolving in terms of an observable time variable. ...
This weakening of the notion of time in classical GR is rarely emphasized: After all, in classical
GR we may disregard the full dynamical structure of the theory and consider only individual solutions of its equations of motion. A single solution of the GR equations of motion determines “a spacetime”, where a notion of proper time is associated to each timelike worldline...
But in the quantum context a single solution of the dynamical equation is like a single “trajectory” of a quantum particle: in quantum theory there are no physical individual trajectories: there are only transition probabilities between observable eigenvalues. Therefore in quantum gravity it is likely to be impossible to describe the world in terms of a spacetime, in the same sense in which the motion of a quantum electron cannot be described in terms of a single trajectory.
A thermal expansion coefficient of spacetime is a measure of how much spacetime expands or contracts in response to changes in temperature. It is similar to the concept of thermal expansion in materials, where an increase in temperature causes the material to expand.
The thermal expansion coefficient of spacetime is measured by observing the changes in the fabric of spacetime in response to changes in temperature. This can be done through experiments and observations of celestial bodies and their movements.
The thermal expansion coefficient of spacetime can be affected by various factors such as the mass and energy density of the universe, the distribution of matter and energy, and the presence of gravitational waves.
A high thermal expansion coefficient of spacetime could indicate that the universe is expanding at an accelerated rate, which could have significant implications for our understanding of the origins and fate of the universe.
Yes, the thermal expansion coefficient of spacetime can change over time as the universe evolves and its properties change. This is why ongoing research and observations are crucial in understanding the nature of spacetime and its expansion.