Talk:Cosmic time

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Want to help write or improve articles about Time? Join WikiProject Time or visit the Time Portal for a list of articles that need improving. -- Yamara 04:47, 13 January 2008 (UTC)[reply]

Merge with Timeline of the Big Bang?

Cosmological timeline forwards to Timeline of the Big Bang. Should this page as well? 72.244.203.5 (talk) 13:27, 25 October 2009 (UTC)[reply]

Nature of time

This writing is interesting because of different time concepts of cosmos and relativistic spacetime.

GR's spacetime is an abstraction, mathematical theoretic model. There ain't any common reference time (like UTC in earth) for all possible observers and simultaneity is observer dependent subjective experience. Spacetime is missing unambiguous simultaneity, common now-moments cannot be defined.

Universe by contrast is a physical existing entity, and has in principle common reference timeline, started from Big Bang and to some extent measurable from cosmic background radiation's (CBR) release moment. In practice, it's time units are coarse, as term "cosmic epoch" indicates. Smallest measurable time units measured from CBR could be something from hundreds to ten thousands of years for the present. So a clock based on CRB wouldn't be very practical. Maybe in far future would?

Essential point is that in principle universe defines a common timeline, hence it could sometime in far future define sufficiently exact basis for simultaneity, what is missing from GR's abstract spacetime.

So this writing could underline this principal viewpoint to general nature of time, what seems not to become apparent elsewhere.

Cosmological time

@Markus Pössel:, is it the same? Should one redirect it here? Wikisaurus (talk) 12:00, 7 May 2020 (UTC)[reply]

@Wikisaurus:: Yes, I believe cosmological time should redirect to cosmic time, not to the chronology of the universe. Markus Pössel (talk) 21:39, 7 May 2020 (UTC)[reply]