The creation of materials without resistance was thought to be impossible, but a Dutch physicist by the name of Heike Kamerlingh Onnes (1853-1926) proved it was possible in 1911. Onnes lowered the temperature of different metals, including mercury, close to absolute zero. He then measured the electrical resistance of the materials at such low temperatures and found that mercury, at only 4.2 kelvin (-277.2°C), had zero resistance to electrical current.