Isotopes of helium a thousand times lower than helium-4 (2.17 K). This difference is explained by quantum statistics, since helium-3 atoms are fermions, while helium-4 atoms are bosons, which condense to a superfluid more easily. The most common isotope, , is produced on Earth by alpha decay of heavier radioactive elements; the alpha particles that emerge are fully ionized nuclei. is an unusually stable nucleus because its nucleons are arranged into complete shells. It was also formed in enormous quantities during Big Bang nucleosynthesis. Terrestrial helium consists almost exclusively (99.99986%) of this isotope. Its boiling point of 4.2 K is the lowest of
Boiling Springs, Pennsylvania States Census Bureau, the CDP has a total area of , of which is land and , or 0.49%, is water. Boiling Springs gets its name from the natural artesian well springs located in and around the town. Boiling Springs ranks seventh in size of springs in the Commonwealth of Pennsylvania. About of water flows per day from a total of 30 springs dotted across approximately . The impression of "boiling" does not result from the temperature of the water, which stays at year-round, but rather from a unique hydrogeological feature. Two vertical diabase dikes, made up of highly impermeable