# Chronometric singularity

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{{short description|Point at which time cannot be described mathematically}}
{{refimprove|date=April 2013}}

In [theoretical physics](/source/theoretical_physics), a '''chronometric singularity''' (also called a '''temporal''' or '''horological''' singularity) is a point at which [time](/source/time) cannot be measured or described.

An example involves a time at a [coordinate singularity](/source/coordinate_singularity), e.g. a [geographical pole](/source/geographical_pole). 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](/source/Theory_of_relativity), similar singularities can be found in the case of [Schwarzschild coordinates](/source/Schwarzschild_coordinates).

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".<ref>[http://www.wisegeek.com/what-is-cosmology.htm What is Cosmology?], wiseGEEK.com. Accessed 15 Feb 2013. In a related discussion, he mentions this again : [http://www.hawking.org.uk/the-beginning-of-time.html The Beginning of Time – Stephen Hawking] {{Webarchive|url=https://web.archive.org/web/20141006200729/http://www.hawking.org.uk/the-beginning-of-time.html |date=2014-10-06 }}; accessed 15 Feb 2013.</ref>

==See also==
*[Coordinate singularity](/source/Coordinate_singularity)
*[No-boundary proposal](/source/No-boundary_proposal) and [imaginary time](/source/imaginary_time)
*[Spacetime singularity](/source/Spacetime_singularity)
*[Time](/source/Time)

==References==
{{reflist}}

Category:Geodesy
Category:Timekeeping

{{geodesy-stub}}

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Adapted from the Wikipedia article [Chronometric singularity](https://en.wikipedia.org/wiki/Chronometric_singularity) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Chronometric_singularity?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.