Worth Reading: A Brief History of Network Time Instead of taking the earth’s rotation as a reference, the CGPM resolved a second should be defined using an extremely stable property of the caesium-133 atom where one of its resonance frequencies is precisely 9,192,631,770 times per second. Atomic clocks were developed that used this property to measure time to an unprecedented level of accuracy [see note below]. Related ← Worth Reading: ACC-Turbo mitigates pulse-wave DDoS attacks using programmable switchesWorth Reading: Management interfaces — attack surface hidden in plain sight →