What is absolute zero?

Absolute zero is defined as the lowest possible temperature that can be achieved, theoretically at 0 Kelvin or -273.15 degrees Celsius. At this temperature, the motion of atoms and molecules is minimal, to the point where they occupy their lowest energy state. This state signifies that there is no thermal energy left in the system, and molecular motion effectively comes to a halt, highlighting the fundamental nature of thermal energy and temperature.

The concept of absolute zero is crucial in the field of thermodynamics and quantum mechanics, as it sets a baseline for the temperature scale and allows scientists to explain various physical phenomena, including the behavior of gases and the properties of matter at extremely low temperatures.