As well as being an accurate description of your bank balance, absolute zero is a term that is bandied about the science and technology world from time to time. So, what is so absolute about this zero? Absolute zero basically refers to 0K (zero degrees Kelvin) or 273.15°C. It is at this temperature that all (or pretty much all) motion in an object ceases. Temperature is basically just the excitation of atoms. The "hotter" something is, the more the atoms in it move around and the "colder" something is, the less they move. As absolute zero is the point at which the particles stop moving altogether, it is impossible for anything to be any colder, it is the absolute lower limit of temperature.* Scientists have been attempting to cool objects to absolute zero for quite some time, but it's basically impossible due to something called Heisenberg's Uncertainty Principle, you may have heard of it. Put simply, the Uncertainty Principle is a law in quantum mechanics that states that it is impossible to know both a particle's momentum and exact position at the same time. If you cooled a particle down to the point where its momentum was zero, you would know both, which is impossible. So you can't get right down to 0K, but you can get close enough to produce some pretty amazing effects. Supercooled materials can become superconductors, meaning that they can conduct electrical currents without resistance. These superconductors can be used in everything from supercomputers to MRI scanners. *Well, until you get into the quantum world, where all bets are off. Incidentally, a sub-absolute-zero quantum gas behaves remarkably like dark energy, so perhaps it's all coming together?
