Most naturally occurring nuclides on earth are beta stable. Nuclides that are not beta stable have half-lives ranging from under a second to periods of time significantly greater than the age of the universe. One common example of a long-lived isotope is the odd-proton odd-neutron nuclide 19 K, which undergoes all three types of beta decay (β, β and electron capture) with a half-life of 1.277 × 10 years.