What is Absolute zero?
[[File:CelsiusKelvin.svg|thumb|right|150px|Zero kelvin (−273.15&nbsp;°C) is defined as absolute zero.]] '''Absolute zero''' is the [[temperature]] at which the [[particles]] of [[matter]] ([[molecule]]s and [[atom]]s) are at their lowest energy points. Some might think that at absolute zero particles lose all energy and stop moving. This is not correct. In [[Quantum mechanics|quantum physics]] there is something called zero point energy, which means that even after all the energy from particles has been removed, the particles still have some energy. This is due to [[Heisenberg's uncertainty principle]], which states that the more that is known about a particle's position, the less that can be known about its momentum, and vice versa. Therefore, a particle cannot be completely stopped because then its exact position and momentum would be known. Some people have created temperatures very close to absolute zero: the record temperature was 100 pK (one hundred [[pico]]kelvin, equal to 10<sup>−10</sup> kelvin) above absolute zero.<ref>reported in the Helsinki University of Technology in 2000.</ref> Even getting close to absolute zero is difficult because anything that touches an object being cooled near absolute zero would give heat to the objects. Scientists use [[lasers]] to slow atoms when cooling objects to very low temperatures.<ref>{{Cite web |url= http://www.cosmosmagazine.com/features/online/2176/verging-absolute-zero |title= Verging on absolute zero |work= cosmosmagazine.com |accessdate= February 2, 2011 |archive-date= November 22, 2008 |archive-url= https://web.archive.org/web/20081122144155/http://www.cosmosmagazine.com/features/online/2176/verging-absolute-zero |url-status= dead }}</ref> The [[kelvin]] and [[Rankine]] temperature scales are defined so that absolute zero is 0 kelvin (K) or 0 degrees Rankine (°R). The [[Celsius]] and [[Fahrenheit]] scales are defined so that absolute zero is −273.15&nbsp;°C or −459.67&nbsp;°F.<ref name=sib2115>{{cite web | title=Unit of thermodynamic temperature (k