Now a flea can have a wristwatch.
NIST researchers have demonstrated a minuscule atomic clock with inner workings about the size of a grain of rice and potential applications in atomically precise timekeeping in portable, battery-powered devices for secure wireless communications, more precise navigation, and other applications. The "physics package" of the clock, believed to be the smallest in the world, is about 1.5 millimeters on a side and about 4 millimeters tall, consumes less than 75 thousandths of a watt, and has a stability of about one part in 10 billion, equivalent to a clock that would neither gain nor lose more than a second in 300 years.
NIST researchers are also demonstrating the potential to fabricate and assemble the physics package using the low-cost, mass-production techniques used to make semiconductor devices, which should eventually lead to a complete atomic clock about 1 cubic centimeter in size (about the size of a pencil eraser) powered by a battery. Such miniature atomic clocks are not intended to compete for accuracy and stability with the world’s most accurate atomic clocks such as the NIST-F1 cesium fountain atomic clock, but could make dramatic improvements in the many consumer and military electronic devices that rely on stable and accurate timing for wireless communications, navigation, and other applications.
My mind is blown. That is a clock. An itty bitty clock. Amazing. Just think where we'll be in twenty years, or fifty.