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
The Sky Has Fallen the gnarliest films I have seen in recent history," adding that it was "on par with Raimi’s "The Evil Dead"." Mark Miller of "Ain't It Cool News" wrote that it was "genuinely creepy and downright scary." Brian Kirst of "Horror Society" said it was "a visual marvel" that "creates both a sympathetic point of view and a world of oozing horror as well." Bella Blitz of "The Horror Honeys" pointed out that the film has "elements of revenge, monsters, slasher, and splatter genres combined." The Sky Has Fallen The Sky Has Fallen is a 2009 American horror film written and