Absolute zero is the lowest temperature in thermodynamics, but it is the lower limit value that only exists in theory. The unit of thermodynamic temperature scale is Kelvin (k), and absolute zero is the zero point defined by Kelvin temperature scale. 0K is about -273. 15 degrees Celsius, which is -459.67 degrees Fahrenheit. The temperature of matter depends on the kinetic energy of atoms, molecules and other particles in it. According to Maxwell-Boltzmann distribution,

The higher the kinetic energy of particles, the higher the temperature of matter. Theoretically, if the kinetic energy of particles is as low as the lowest point of quantum mechanics, the matter will reach absolute zero and cannot be lower. But absolute zero can never be achieved, only infinitely close.

Because there must be energy and heat in any space, and they are constantly transforming each other without disappearing. So absolute zero does not exist unless there is no energy and heat in space from the beginning.