Kalpa

Kalpa is a period of time measurement used in Indian astronomy equal to 4,32,00,00,000 years.

A kalpa is 1000 times longer than the mahāyuga, within which are contained the four ages (including our own age, Kaliyuga). The mahāyuga, of course, being 4,32,00,000 years.

Two Kalpas were considered one day-and-night for Brahmā. The Sūrya Siddhānta says it "brings about the destruction of all that exists".