With the end of the Cold War, and with telecommunications technology advancing rapidly, surplus stores and eBay have filled up with discarded precision time equipment once beyond the reach of all but governments. Cesium clocks, rubidium clocks and even the occasional hydrogen maser can be had for less than a decent laptop. A recent search on eBay turned up an HP 5061B cesium standard for sale for $2,000, and you can get a telecom surplus rubidium standard for less than $400. Some of this equipment costs upwards of $50,000 new.

Their access to once-forbidden technology lets the time hackers play in a realm of precision that underpins the modern technological world. A select few, like Van Baak, have started exploring the underpinnings of the universe.

Amateur Time Hackers Play With Atomic Clocks at Home