A chronometric singularity (also called a temporal or horological singularity) is a point at which time cannot be measured or described.
An example involves a time at a coordinate
singularity, e.g.a
geographical pole
A geographical pole or geographic pole is either of the two points on Earth where its axis of rotation intersects its surface. The North Pole lies in the Arctic Ocean while the South Pole is in Antarctica. North and South poles are also define ...
. Since time on Earth is measured through longitudes, and no unique longitude exists at a pole, time is not defined uniquely at this point. There is a clear connection with
coordinate singularities, as can be seen from this example. In relativity, similar singularities can be found in the case of
Schwarzschild coordinates In the theory of Lorentzian manifolds, spherically symmetric spacetimes admit a family of ''nested round spheres''. In such a spacetime, a particularly important kind of coordinate chart is the Schwarzschild chart, a kind of polar spherical coordi ...
.
Stephen Hawking once compared by a talk-show guest's question about "before the beginning of time" to asking "what's north of the north pole".
What is Cosmology?
wiseGEEK.com. Accessed 15 Feb 2013. In a related discussion, he mentions this again
; accessed 15 Feb 2013.
See also
*Coordinate singularity A coordinate singularity occurs when an apparent singularity or discontinuity occurs in one coordinate frame that can be removed by choosing a different frame.
An example is the apparent (longitudinal) singularity at the 90 degree latitude in sph ...
* No-boundary proposal and imaginary time
Imaginary time is a mathematical representation of time which appears in some approaches to special relativity and quantum mechanics. It finds uses in connecting quantum mechanics with statistical mechanics and in certain cosmological theories.
...
*Spacetime singularity
A gravitational singularity, spacetime singularity or simply singularity is a condition in which gravity is so intense that spacetime itself breaks down catastrophically. As such, a singularity is by definition no longer part of the regular sp ...
*Time
Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, to ...
References
Geodesy
Timekeeping
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