Change shows time {time, physics}. Time orders changes.
direction
Time flows forward, not backward. Time changes are never symmetric. Locally, time changes can be almost symmetric if no change happens.
isosynchrony
Because universe is homogeneous, time flows almost the same everywhere.
physical laws
Physical laws are time-symmetric now, except for neutral kaon decay. Physical laws are always parity-charge-time symmetric. Reasoning works the same in both time directions.
imaginary time
Space-time has real time, which has direction. Space-time can have imaginary time {imaginary time}, which has no direction. If time has imaginary-number component, time is complex number and can have more than one dimension. Real-number time always increases, but imaginary-number time can be decreasing or increasing, just like spatial dimension. Real-number time is always positive, but time measured by imaginary numbers can be negative or positive. Having imaginary-number time dimension does not change physical laws. Having imaginary-number time dimension allows time to stand still. It also allows space not to have singularities.
origin
How did time arise? What causes number of time dimensions? Perhaps, time and space result from object interactions. Perhaps, motion necessity and nature create and require one long-range time dimension. More than one time dimension provides too many possibilities and cannot be stable. Less than one time dimension causes immobility. Perhaps, space and time result from induction.
origin: symmetry
Perhaps, the only allowable or most probable universes are asymmetric in time, though physical laws are symmetric in time. Perhaps, only asymmetric universes support life or intelligent life.
Physical Sciences>Physics>Time
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Date Modified: 2022.0224