Scientists in Denmark have made a curious and awesome discovery - cooled down, solid laughing gas can contain an enormous electric field.
The discovery occurred when physicists at Aarhus University were observing how electrons travel through nitrous oxide, or 'laughing gas', frozen to minus 233 degrees Celsius. When brought down to this temperature, the gas formed a thin, solid film, about one tenth of a micron thick, hovering over a strip of gold.
It was supposed to be a routine experiment, but the team soon realised something was amiss. A potential of around 14.5 volts appeared spontaneously on the film, which in turn produced an enormous electrical field of more than 100 million volts per metre. Based on widely accepted notions in physics, there should have been no electric current whatsoever.
"They came upstairs and knocked on my door, saying ‘David, there's something not right’. At first we thought the experiment had gone wrong, because it wasn't supposed to be possible for a current to pass through the film and be detected. No external voltage was applied,” physicist David Field told Lise Brix at ScienceNordic.
Further testing confirmed that what they’d found is a brand new electrical phenomenon, which Field is calling ‘spontelectric’. The team has published their findings in the journal Physical Chemistry Chemical Physics.
The scientists looked for spontelectric events on other common substances, such as carbon monoxide, toluene, propane, and methyl formate. They cooled them all down to temperatures below minus 200 degrees Celsius and looked for an electric field.
Sometimes they needed to apply many layers above their gold strip before they would see the electric field appear. "When the experiment is conducted with toluene at 75 Kelvin, minus 198 degrees Celsius, more than a hundred layers are necessary for the effect to occur,” Field told Brix.
"This is the first time since the 1920s that anyone has discovered a new electrical form of solid material,” he adds. "The incredible thing is that work has been done on thin layers of materials - including laughing gas films - for more than half a century. Even so, no one has discovered this powerful electrical phenomenon."
Exactly why or how it happens remains a bit of a mystery, but the team suspects it has to do with laughing gas being made up of dipolar molecules, which act sort of like magnets. Each one tries to arrange itself so its south pole is facing the north pole of its neighbouring dipole molecule, which will do the same, and so on. This means the molecular structure of laughing gas will end up with slightly more negative charge on one end than on the other.
But when the electric field spontaneously occurs, it does something weird to these individual molecules. They do the opposite of what they’d normally do.
“The laughing gas molecules in the upper layer will arrange themselves in such a way that the positive end of the molecule pokes up towards the surface,” reports Brix at ScienceNordic, "creating a voltage on the surface of the film."
According to Brix, Field is hoping to use the discovery to learn more about how stars form. He says that star-forming clouds are super-cold in the middle, which means there’s a possibility that spontelectric carbon monoxide could be present inside them, and may induce the process of star creation.
Only science can take us from laughing gas to actual stars because of a chance discovery in the lab. And thats why we love it.