Absolute zero is the lowest possible temperature that can be achieved, at which all molecular motion ceases. It is equivalent to 0 Kelvin or -273.15 degrees Celsius.
At absolute zero, atoms have no thermal energy and are in their ground state, meaning they are at their lowest possible energy level. This causes them to stop vibrating and moving, resulting in a loss of atomic bonds and a decrease in atomic size.
At higher temperatures, atoms have more energy and are in a constant state of motion. This causes them to vibrate, rotate, and move around, resulting in chemical reactions and physical changes. However, at absolute zero, the atoms are frozen in place and do not exhibit any of these behaviors.
Studying atoms at absolute zero allows us to understand the fundamental properties and behaviors of matter. It also helps us to develop new technologies, such as superconductors and quantum computers, which rely on controlling atoms at extremely low temperatures.
It is theoretically impossible to reach absolute zero, as it would require removing all energy from a system. However, scientists have been able to cool atoms to within a few billionths of a degree above absolute zero, allowing for further research and understanding of this extreme temperature.