Why does absolute zero correspond to …

• Absolute zero is the lowest possible temperature where nothing could be colder and no heat energy remains in a substance.
• Absolute zero is the point at which the fundamental particles of nature have minimal vibrational motion, retaining only quantum mechanical, zero-point energy-induced particle motion.
• By international agreement, absolute zero is defined as precisely; 0 K on the Kelvin scale, which is a thermodynamic (absolute) temperature scale; and –273.15 degrees Celsius on the Celsius scale.
• Absolute zero is also precisely equivalent to; 0 degrees R on the Rankine scale (also a thermodynamic temperature scale); and –459.67 degrees F on the Fahrenheit scale.
• While scientists can not fully achieve a state of “zero” heat energy in a substance, they have made great advancements in achieving temperatures ever closer to absolute zero (where matter exhibits odd quantum effects).
• In 1994, the NIST achieved a record cold temperature of 700 nK (billionths of a kelvin).
• In 2003, researchers at MIT eclipsed this with a new record of 450 pK (0.45 nK).

Therefore, absolute zero corresponds to the level of zero energy.

At absolute zero, all motion comes to a standstill. A lower temperature is not feasible because there is no velocity smaller than zero and no energy content less than nothing. Energy in this instance means only the energy that can be taken away from the particles and does not include the rest mass or quantum mechanical zero-point energies for confined particles.That's why it corresponds to zero energy. Absolute zero corresponds to –273 degrees Celsius and –460 degrees Fahrenheit.

Temperature: it is a measure of the energy content of matter. When air is hot, the molecules move fast and they have high kinetic energy. The colder the molecules are, the smaller their velocities are and, subsequently, their energy.