Helium is the second-most common element in the universe, but it’s comparatively rare on Earth. It also fulfills a surprising role in everything from space exploration to quantum computing.
New discoveries, everyday mysteries and the science behind the headlines — all in about 10 minutes, every weekday. Short Wave is science for everyone, using a lot of creativity and a little humor. Subscribe to the podcast, and follow @NPRScience on Twitter.
Short Wave is celebrating the 150th anniversary of the periodic table with profiles of some of its favorite elements. Here are five things you may not have known about helium.
Helium is the only element on the planet that is a completely nonrenewable resource.
On Earth, helium is generated deep underground through the natural radioactive decay of elements such as uranium and thorium. “It takes many, many millennia to make the helium that’s here on the Earth,” says Sophia Hayes, a chemist at Washington University in St. Louis. The helium seeps up through the Earth’s crust and gets trapped in pockets of natural gas, where it can be extracted.
Like hydrogen, its immediate predecessor on the periodic table, helium is lightweight. But unlike hydrogen, it doesn’t readily combine with other elements. So, once helium reaches the surface, it can easily escape the Earth’s gravitational pull.
Other resources, such as oil and gas, may turn into pollution or be difficult to recycle. But only helium physically disappears from the planet. “It’s the one element out of the entire periodic table that escapes the Earth and goes out into outer space,” Hayes says.
America once thought helium would turn the tide of war.
During World War I, aviation was still in its infancy, and dirigibles were considered cutting-edge weapons of war. German zeppelins were the strategic weapons of their time, drifting over civilian targets and dropping bombs from their gondolas.
But zeppelins had a critical vulnerability: They were filled with highly flammable hydrogen. After a few zeppelin raids over London, British troops developed incendiary bullets that would “light up the hydrogen in the dirigibles,” says David Aubin, a professor for the history of science at Sorbonne Université in Paris.
Meanwhile, American scientists had just discovered large helium deposits in natural gas fields in places like Kansas. Aubin says the government quickly nationalized its nonflammable helium supply and rushed it to Europe to fill attack blimps.
The helium was not used before the war ended, Aubin says, but “they had thousands of cylinders filled, on the docks at New Orleans ready to be shipped to Europe in November of 1918, so it would have been used very soon.”
In fact, in March of 1919, Assistant Secretary of the Navy Franklin D. Roosevelt told The New York Times: “If the war had lasted until next spring, the British and American Governments would have sent helium-filled rigid airships over strategic points in Germany, each capable of dropping a ‘total of 10 tons or more of high explosives.”
The U.S. continued to control the world’s helium supply after the war (this is why the famous German zeppelin Hindenburg was filled with hydrogen when it exploded in 1937). And the military continued to experiment with airships until World War II, when it became clear that fixed-wing aircraft provided numerous advantages.
Helium was essential to the first missions to the moon.
A rocket is basically two very big tanks: In one tank is the fuel, and in the other, is the oxidizer, usually oxygen. As the fuel and oxidizer flow out of the tanks, they leave a vacuum behind, which can cause the fuel to stop flowing.
The solution is injecting another gas to push the fuel out. That gas should be lightweight, highly compressible, so it doesn’t take up much space, and unreactive, so it doesn’t mess with the fuel. Helium turns out to be perfect for the job.
Helium was used in the giant Saturn V rockets that carried Apollo astronauts into space. It was also used in the command and service module that went to the moon and in the lunar lander that carried Neil Armstrong and Buzz Aldrin to and from the surface.
The helium used in the Apollo program actually came from the Strategic Helium Reserve outside of Amarillo, Texas. The reserve was started toward the end of World War I, as part of a government effort to maintain a strategic supply of helium.
Today, helium is high-tech
Helium is in demand today, but for very different reasons than it was in the last century. This time around, much of the demand has to do with helium’s ability to liquefy at very low temperatures — just 4.2 degrees Kelvin (−452.1 F).
“Sometimes my astrophysics colleagues tell me that the temperature of outer space is 3 Kelvin,” Hayes says. “So it’s just one degree different than the temperature of outer space, that’s how cold it is.”
Hayes runs a laboratory that uses very special materials called superconductors. Electricity can flow through these materials with no resistance at all. “That creates very, very large magnetic fields,” she says.
Hayes uses those fields to study chemical processes, but they are also used in medicine to image the human body. Magnetic resonance imaging, or MRI, technology uses superconductors cooled by liquid helium.
Hannah Benet /Google
And that’s not the only application. Superconducting bits are also at the heart of some of the most advanced quantum computers currently being developed. Google recently said one computer it developed had beaten the world’s fastest conventional computer when conducting a specialized calculation. Such “quantum supremacy,” if it continues to develop, could eventually allow intelligence agencies to crack virtually any code.
Helium in its gaseous form is also used in the fabrication of conventional electronics, and it continues to be used in rockets by cutting-edge companies like SpaceX.
But it’s also in short supply.
The world’s helium supply is still located in just a handful of countries: The United States, Algeria and Qatar. If any one of those countries experiences a problem with production, the price of helium can spike, Hayes says.
The constant volatility in helium prices is forcing researchers to reconsider how they use the gas, she says. In fact, she has been forced to mothball some of her superconducting magnets because the price is too high. She worries that unless the price volatility can be brought under control, research in a variety of important areas will be curtailed or even abandoned.
Other nations, including Russia and South Africa, are mulling getting into the helium production business, which may help alleviate the periodic shortages. Until they do, should average people give up their helium balloons? Hayes says no: “I am not a balloon denier. The helium that’s used in party balloons gets everybody to care about this resource.”
This is a syndicated post. Read the original post at Source link .