At this point the scientifically acute in the crowd might raise their hands and say, “Yeah, but isn’t the universe itself only 13.8 billion years old?” Correct. And the multiplexed clock in question loses one second every 300 billion years, i.e. 22 times the length of the universe’s current age. Some might wonder, then: “What’s the point? Isn’t my super cool quartz Swatch enough?” Sure, timekeeping methods like quartz are far more accurate than straight-up mechanical timekeepers. Quartz vibrates over 32,000 times per second when conducting electricity, which is why quartz clocks regulate mechanical clock parts so precisely. NASA says that the best quartz clocks lose only one billionth of a second every hour.
Such a loss in accuracy doesn’t matter on Earth. But up in space? The slightest loss of time in communication between a spacecraft and Earth means errors of hundreds of kilometers in navigation, as NASA explains. This is why the agency is developing its Deep Space Atomic Clock — which adds mercury molecules to a quartz clock — to help ships navigate. When struck by microwaves, the electrons in these molecules jump to different energy shells that produce varying wavelengths. Measuring these wavelengths gives us a clock that only loses one second every 10 million years.
Optical clocks are even more accurate than atomic clocks because they shoot quartz with light instead of microwaves. And the new University of Wisconsin-Madison clock? It’s made of six interlocking optical clocks.
