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An object's absolute temperature therefore describes how much warmer the object is than absolute zero. While temperature is a measure of the heat of an object, heat itself is simply a highly abstract consideration of the kinetic energy of the molecular particles of the object. At absolute zero, we have reached the baseline. The absolute temperature measures the movement among the particles of an object by comparing it to the state of an object at absolute zero.
Absolute zero was first calculated by using the Ideal gas law, and sometimes absolute zero is defined as the temperature at which an Ideal gas has no volume and exerts no pressure. The problem with this definition is that an ideal gas does not exist, as an ideal gas does not liquefy. All known gases will liquefy before getting to 0 K.
According to the kinetic theory there would at absolute zero be no movement of individual particles and thus any material at this temperature would be solid. This has been proven false and it's better to describe absolute zero as the temperature where no further energy may be extracted. For the case of free atoms at temperatures approaching absolute zero, most of the energy is in the form of translational motion and the temperature can be measured in terms of the speed of this motion, with slower speeds corresponding to lower temperatures. In fact because of quantum mechanical effects, the speed at absolute zero is not precisely zero, but depends, as does the energy, on the size of space within which the atom is confined. At absolute zero the molecules and atoms in a system are all in the ground state (i.e. the lowest possible energy state) and the system has the least possible amount of kinetic energy allowed by the laws of physics. This minimum energy corresponds to the zero-point energy encountered in the quantum mechanical particle in a box problem. As mentioned above, the lowest possible energy is not necessarily zero energy, due to the ramifications of quantum theory.
It can be shown from the laws of thermodynamicsThermodynamics is the physics of energy, heat, work, entropy and the spontaneity of processes. Thermodynamics is closely related to statistical mechanics from which many thermodynamic relationships can be derived. While dealing with processes in which sys that the temperature can never be exactly absolute zero; this is the same principle that ensures no system may be 100% efficient, although it is possible to achieve temperatures arbitrarily close to it. At very low temperatures in the vicinity of absolute zero, matter exhibits many unusual properties including superconductivity, superfluiditySuperfluidity is a phase of matter characterised by the complete absence of viscosity. Thus superfluids, placed in a closed loop, can flow endlessly without friction. Superfluidity was discovered by Pyotr Leonidovich Kapitsa, John F. Allen, and Don Misene, and Bose-Einstein condensationA Bose-Einstein condensate is a gaseous superfluid phase formed by atoms cooled to temperatures very near to absolute zero. The first such condensate was produced by Eric Cornell and Carl Wieman in 1995, using a gas of rubidium atoms cooled to one twenty-. In order to study such phenomena, scientists have worked to obtain ever lower temperatures. As of 2004, the lowest temperature Bose-Einstein condensate achieved was 450 pKTo help compare different orders of magnitude this page lists temperatures between 1 picokelvin (10-12 K) and 1 nanokelvin (10-9 K). Temperatures lower than 1 pK 250pK (2. 5 × 10-10) Lowest temperature ever produced , during an experiment on nuclear magne, or 4.5 ×10-10 K. This was performed by Wolfgang Ketterle and colleagues at the Massachusetts Institute of Technology (A Leanhardt et al. 2003 Science 301 1513). [1]. The coldest temperature ever produced was 250 pK [2] during an experiment on nuclear magnetic ordering in the Helsinki University of Technology's Low Temperature Lab.
The Boomerang nebula has recently been discovered to be the coldest place known outside a laboratory, being only -272 degrees Celsius (1 kelvin). The nebula is 5,000 light-years from Earth (in the constellation Centaurus). [3]
For some special systems and specific definitions of temperature, it is possible to obtain a negative temperature. A system with a negative temperature is not colder than absolute zero, rather it is - in a sense - hotter than infinite temperature.
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