Alex Kehagias

A black hole has three laws, just like an ideal gas. The first: energy is conserved. The second: the horizon area never decreases. And the third, the most finicky, demands that at zero temperature the entropy (a measure of disorder) tend to zero or a universal constant.

A fussy thermometer shows different temperatures depending on who is looking at it. A black hole behaves much the same way: its thermal properties, entropy and temperature, depend on how we describe the information hidden inside.

In the shaft leading to the Large Hadron Collider, an unusual tenant may soon move in: a hundred-meter vertical tube where clouds of strontium atoms will be dropped. Each cloud is cooled to near absolute zero, so the atoms move slowly and in sync, like dancers in slow motion.