Our objective is to formulate questions about time in their true setting — cosmology. Even to formulate these questions one needs a theory. But, for cosmology, the available theories are unsatisfactory and the slender empirical evidence admits a diversity of interpretations.
We review the evidence for an expanding, finite-age cosmos, using general relativity and in relation to questions about the global structure of time. In interpreting the evidence we emphasize the implicit assumptions, which often go unstated.
We conclude by formulating a number of questions about time. Is there a proper clock? What is the exact relationship between the time asymmetries? Is time asymmetry imperfect? Could it be local? Is the notion of an asymmetry conceptually adequate to capture a sufficient variety of structures of time?
KeywordsDark Matter Cosmological Time Closed Timelike Curve Time Asymmetry Foucault Pendulum
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Notes and References
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