Entropy
Entropy was a thermodynamic quantity representing the unavailability of a system's thermal energy for conversion into mechanical work.

In 2370, Jadzia Dax discovered local entropy readings in a protouniverse had decreased 12% in the previous 58 minutes, indicating there was life within the protouniverse. ()

In an alternate 2379, The Doctor exposed Kes to a biotemporal field in order to push her s back to an earlier stage of entropic decay and thereby extend her life. Instead it reactivated dormant chronitons in her body, taking her out of temporal sync and back in time. ()

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physics