An atomic watch is just a wrist away . . .

American scientists discovered a way to reduce the size of an atomic
clock, which measures time using a ray of light to count vibrations,
to the size of a grain of rice.
The new clock only uses about 73 Mili-Watt's and can reach an accuracy
of being off by a second every 300 years.
The estimated, initial, retail price for such watches is 100 USD;
about the price of a quartz watch.