Helium
hideHelium (pronounced /ˈhiːliəm/) is the chemical element with atomic number 2, and is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert monatomic gas that heads the noble gas group in the periodic table. Its boiling and melting points are the lowest among the elements and it exists only as a gas except in extreme conditions.
An unknown yellow spectral line signature in sunlight was first observed from a solar eclipse in 1868 by French astronomer Pierre Janssen. Janssen is jointly credited with the discovery of the element with Norman Lockyer, who observed the same eclipse and was the first to propose that the line was due to a new element which he named helium. In 1903, large reserves of helium were found in the natural gas fields of the United States, which is by far the largest supplier of the gas. Helium is used in cryogenics, in deep-sea breathing systems, to cool superconducting magnets, in helium dating, for inflating balloons, for providing lift in airships and as a protective gas for many industrial uses (such as arc welding and growing silicon wafers). Inhaling a small volume of the gas temporarily changes the timbre and quality of the human voice. The behavior of liquid helium-4's two fluid phases, helium I and helium II, is important to researchers studying quantum mechanics (in particular the phenomenon of superfluidity) and to those looking at the effects that temperatures near absolute zero have on matter (such as superconductivity).
Helium is the second lightest element and is the second most abundant in the observable universe, being present in in the universe in masses more than 12 times those of all the other elements heavier than helium combined. Helium's abundance is also similar to this in our own Sun and Jupiter. This high abundance is due to the very high binding energy (per nucleon) of helium-4 with respect to the next three elements after helium (lithium, beryllium, and boron). This helium-4 binding energy also accounts for its commonality as a product in both nuclear fusion and radioactive decay. Most helium in the universe is helium-4, and was formed during the Big Bang. Some new helium is being created presently as a result of the nuclear fusion of hydrogen, in all but the very heaviest stars, which fuse helium into heavier elements at the extreme ends of their lives.
On Earth, the lightness of helium has caused its evaporation from the gas and dust cloud from which the planet condensed, and it is thus relatively rare. What helium is present today has been mostly created by the natural radioactive decay of heavy radioactive elements (thorium and uranium), as the alpha particles that are emitted by such decays consist of helium-4 nuclei. This radiogenic helium is trapped with natural gas in concentrations up to seven percent by volume, from which it is extracted commercially by a low-temperature separation process called fractional distillation.
For more information about Helium, read the full article at
Wikipedia.
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News tagged with helium
Proton's party pals may alter its internal structure
Nov 18, 2009 |
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A recent experiment at the DOE's Thomas Jefferson National Accelerator Facility has found that a proton's nearest neighbors in the nucleus of the atom may modify the proton's internal structure.
Two Earth-sized bodies with oxygen rich atmospheres found -- but they're stars not planets
Nov 12, 2009 |
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(PhysOrg.com) -- Astrophysicists at the University of Warwick and Kiel University have discovered two earth sized bodies with oxygen rich atmospheres - however there is a bit of a disappointing snag for anyone ...
WISE Is Chilling Out
Space & Earth / Space Exploration
Nov 11, 2009 |
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(PhysOrg.com) -- Engineers are busy cooling the science instrument on NASA's Wide-field Infrared Survey Explorer, or WISE. The spacecraft is scheduled to blast into space from Vandenberg Air Force Base in ...
A bubbling ball of gas (w/ Video)
Space & Earth / Space Exploration
Nov 11, 2009 |
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The Sun is a bubbling mass. Packages of gas rise and sink, lending the sun its grainy surface structure, its granulation. Dark spots appear and disappear, clouds of matter dart up - and behind the whole thing ...
High-performance plasmas may make reliable, efficient fusion power a reality
Nov 02, 2009 |
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In the quest to produce nuclear fusion energy, researchers from the DIII-D National Fusion Facility have recently confirmed long-standing theoretical predictions that performance, efficiency and reliability ...
Dark Matter in a Galaxy
Oct 30, 2009 |
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(PhysOrg.com) -- Stars, the most familiar objects in the night sky, make up only a tiny percentage of the total amount of matter in the universe -- about 2%.
LHC now colder than deep space
Oct 20, 2009 |
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(PhysOrg.com) -- The LHC (Large Hadron Collider) is once again colder than deep space as it is prepared for experiments to resume in late November.
MIT Student Takes Pictures from Space on Less Than $150 (w/ Video)
Oct 02, 2009 |
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(PhysOrg.com) -- When we think of taking pictures of the earth from space, we assume that a great deal of money has to be spent on high-tech equipment and complex vehicles to get the camera up there. But, ...
The Hot Saturn Exoplanet
Oct 02, 2009 |
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(PhysOrg.com) -- Of the roughly 350 known exoplanets (i.e., extrasolar planets), the one orbiting the star HD149026 is unique.
Prototype Method Detects and Measures Elusive Hazards
Chemistry / Analytical Chemistry
Sep 08, 2009 |
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(PhysOrg.com) -- A chemist at the National Institute of Standards and Technology has demonstrated a relatively simple, inexpensive method for detecting and measuring elusive hazards such as concealed explosives ...
Particle collider: Black hole or crucial machine?
Aug 07, 2009 |
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(AP) -- When launched to great fanfare nearly a year ago, some feared the Large Hadron Collider would create a black hole that would suck in the world. It turns out the Hadron may be the black hole.
Restart of Large Hadron Collider now November
Jul 30, 2009 |
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(AP) -- Repairs to two small helium leaks in the world's largest atom smasher will delay the restart of the giant machine another month until November, a spokesman for the operator said Thursday.
Scientists bid adieu to plucky solar probe
Space & Earth / Space Exploration
Jun 30, 2009 |
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US and European scientists were Tuesday bidding farewell to the tenacious solar probe Ulysses which has been recording data around the sun for more than 18 years, four times longer than planned.
Scientists Create Smallest Ever Droplet of Acid, Solve Ozone Puzzle
Chemistry / Analytical Chemistry
Jun 25, 2009 |
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(PhysOrg.com) -- In its atomic form, chlorine can destroy vast quantities of ozone. But exactly how chlorine is created in the ultracold conditions of the stratosphere has puzzled scientists. Now, a team of ...
Researchers putting a freeze on oscillator vibrations
Jun 17, 2009 |
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University of Oregon physicists have successfully landed a one-two punch on a tiny glass sphere, refrigerating it in liquid helium and then dosing its perimeter with a laser beam, to bring its naturally occurring mechanical ...
