Absolute Zero The Race to the Coldest Place in the Universe

Heat seems to have no ceiling. Stars burn at millions of degrees, and the core of a collapsing star goes higher still. Cold is different. Cold has a floor, a temperature below which nothing can go because there is nothing left to take away. Physicists call it absolute zero, and it sits at minus 273.15 degrees Celsius, or minus 459.67 Fahrenheit.

To feel how far away that is, consider the most punishing cold that people have actually lived through. A century ago, Antarctic explorers pushed toward the South Pole, where temperatures can plummet to around minus 80. That is a cold that cracks teeth and freezes breath into the beard. It is also nearly two hundred degrees warmer than the floor. The explorers were racing across the ice. The physicists who came to chase absolute zero were racing across something stranger, a scale of temperature that gets harder to descend with every step.

This is the story of that descent. It starts with a French instrument maker staring at a column of air, passes through a Scottish lord with a gift for turning a vague idea into a law, and runs through the long struggle to turn gases into liquids. Along the way it uncovers metals that carry current forever, liquids that climb out of their own containers, and finally clouds of atoms so cold they stop behaving like individual things at all. Every step toward the floor revealed that matter, left with almost no heat, does things nobody had thought to expect.