Short answers, pulled from the story.
Lord Rayleigh and Sir William Ramsay discovered argon in 1894 at University College London. They identified the gas after stripping air of oxygen, carbon dioxide, water, and nitrogen to find an unreactive substance.
Argon-40 makes up 99.6% of natural argon found on our planet. This isotope forms from the decay of potassium-40 in rocks over billions of years.
Industrial facilities extract roughly 700,000 tonnes of argon every year from liquid air. Cryogenic fractional distillation separates this gas from nitrogen and oxygen inside massive separation units.
Researchers at the University of Helsinki finally created argon fluorohydride in August 2000. The resulting molecule remained stable only below minus 256 degrees Celsius or 17 kelvins.
Liquid argon serves as the target material for neutrino experiments searching for dark matter particles. Detectors like ICARUS and MicroBooNE use time projection chambers to image three-dimensional neutrino interactions within the liquid.