© Ken McGee/U.S. Geological SurveyPlumes of steam rise up from many spots along the Firehole River in Yellowstone National Park.
Yellowstone National Park's geysers, hot springs, fumaroles and other
hydrothermal features spew out a collection of
gases from deep within the Earth - steam, carbon dioxide, methane, neon, argon and helium. There's not enough of that last one, helium, for the park to start selling balloons or for visitors to sound like
chipmunks, but there's plenty for scientists to study.
Helium can bubble out of volcanic rocks that drive hydrothermal activity, but that's not where most of Yellowstone's helium is coming from, it seems. The park's gas originates deep in rocks where it's been stored for hundreds of millions of years, U.S. Geological Survey scientists
report today in
Nature.
Helium is the second-most abundant element in the universe - it's formed by the nuclear fusion of hydrogen atoms, a process that
powers stars - but it's pretty rare here on Earth. Lucky for birthday-party goers and clowns (and modern
medicine), helium can be extracted from reserves of
natural gas underground.
Helium on Earth can be found in
two main forms: Nearly all occurs as helium-4 (named thus because it has two protons and two neutrons), which can be produced during the
radioactive decay of heavy elements such as uranium. A tiny fraction (about one in a million) occurs as
helium-3 (two protons and one neutron), most of which has been present on Earth since the planet's formation and is a vestige of material that originally formed the planet.
Comment: There is evidence that these environmental events may be caused by a companion star to the Sun:
"Check out the Wikipedia page on the so-called 'Nemesis' hypothesis. (And see here for additional resources.) It was introduced in 1984 by two teams of astronomers (Whitmire & Jackson, and Davis, Hut & Muller) to explain the periodically spaced extinction events observed in the earth's fossil record. The idea was that a companion sun passing through or close to the spherical Oort cloud would send a death-dealing swarm of comets in earth's direction every 26 million years or so. Its presence may also help explain the non-random trajectories of certain long-period comets, as well as the strange and unexpected elliptical orbit of the recently discovered transneptunian object Sedna."
You can read more here: The Cs Hit List 07: Sun Star Companion, Singing Stones and Smoking Visions