Chronological Order
 Tampan, Paminggir people. Lampung region of Sumatra, circa 1900, 49 x 53 cm. From the library of Darwin Sjamsudin, Jakarta. Photograph by D Dunlop.

Consider a particle P that is described by the chain of events

$\Psi ^{\sf{P}} = \left( \sf{P}_{1} , \sf{P}_{2} \: \ldots \: \sf{P}_{\it{k}} \: \ldots \right)$

where the phase of events is given by

$\delta _{\theta} \, \left( \sf{P}_{ \it{k}} \right) = (-1)^{\it{k}} = \pm1$

so that $\delta _{\theta}$ alternates back and forth between plus and minus one for consecutive events along the chain. Definition: if a chain of events like this is also in historical order, then we say it is in chronological order.

Sensory interpretation: If the Earth is used as a reference frame, and the brightness of daily events on Earth determines the phase, then $\Psi$ is a chain of events that alternates between day-time and and night-time incidents in the same order as the calendar date.
 Next step: other clocks.

Related WikiMechanics articles.

 Summary
 Adjective Definition Chronological Order $\delta _{\theta} \, \left( \sf{P}_{ \it{k}} \right) = (-1)^{\it{k}} = \pm1$ 6-24
page revision: 140, last edited: 08 Oct 2017 13:12