The clock was developed by JILA, a joint institute of the National Institute of Standards and Technology (NIST) and the University of Colorado Boulder. Its new capabilities are reported in a paper published Tuesday in Nature Communications.
Here's lead researcher Jun Ye describing the clock back in 2009, when it was a measly 200 million years of accuracy we were talking about:
The clock works around several thousand atoms of the element strontium. Intense laser lights form what's called an optical lattice, creating a 30-by-30 micrometer column to hold the atoms in. The clock then uses a stable red laser to make the atoms switch between two different energy levels. In theory, every "tick," or switch between energy levels, should be exactly the same, making these atoms much more accurate "pendulums" than the ones that swing in regular clocks.
To make the clock more accurate (meaning that it represents the actual time that it takes a strontium atom to "tick") and stable (meaning that its ticks are all alike), the researchers have worked to reduce the influence of heat from the clock's surrounding environment, which can affect the speed at which the atoms respond to the laser.
The new clock is so accurate that, as NPR reported last year, it actually makes it difficult to know what time it even is. It's accurate enough that it picks up on the slight differences in the passage of time at different heights (thanks, relativity), so it raises the question of whether the whole Earth can really have one standard, super-accurate clock that speaks for us all. Should we tell time by our highest points or our lowest? It's kind of mind-boggling.
Want more science? Give these a click: