Atomic clocks keep time better than any other clock. They even keep time better than the rotation of the Earth and the movement of the stars. Without atomic clocks, GPS navigation would be impossible, the Internet would not synchronize, and the position of the planets would not be known with enough accuracy for space probes and landers to be launched and monitored.
Elprime Clock Pro can synchronize your computer time with a large number of atomic clock servers around the world:
You can connect to atomic time server to test time at server to check your clock accuracy as well as instantly synchronize your computer clock with atomic clock.