Atoms vibrate at consistent rates. International time - standard clocks regulated by atomic vibrations are accurate to 1 second in 80 million years.
كَمَا أَنَّ ٱلْكَوَاكِبَ وَٱلنُّجُومَ تَتْبَعُ فِي حَرَكَتِهَا تَوْقِيتًا دَقِيقًا لِلْغَايَةِ .‏