Absolute zero is the lowest temperature theoretically possible. At absolute zero atoms have the minimum amount of vibration (i.e., motion) possible. Although this state cannot be achieved physically, the temperature has been extrapolated from experimental data beginning with observations correlating decreasing pressure and temperature in gases. This temperature is -459.69°F, or 0K on the Kelvin scale (-273.16°C, 0°R on the Rakine scale).

Heat is actually the motion of atoms. The hotter something seems to be, the faster its atoms are moving, vibrating back and forth. If the vibrations become frenzied enough, phase transitions can occur, such as when boiling water changes to steam. Conversely, when vibrations slow, cooling takes place, as when water freezes to ice. Just as the velocity of objects can approach but never reach the speed of light, however, neither can atoms be absolutely motionless. At this...