"Absolute zero" is 0 Kelvins or -273.15°C. Since the lowest recorded temperate on Earth was warmer than -100°C (see http://www.answerbag.com/c_view.php/132#q_2389 ), this temperature has never been reached naturally here on Earth. Triton, a moon of Neptune, is said to be the coldest place in our solar system with a temperature of -235°C or 38K. This still warmer than "absolute zero". Outer space has been said to have a temperature of 2.73K or -270.42°C. This is close to "absolute zero" but not close enough. Liquid helium has a temperature of around 1.3K or -271.85°C. An apparatus called a "dilution refrigerator" manages to use a rare helium isotope (3He) to reach 0.002 K or -273.148°. Still not cold enough, but getting very close. While we have artificially come very close to reach absolute zero, it has not happened naturally. As well, apparently the third law of thermodynamics prevents us from reaching absolute zero. For more information on absolute zero, visit http://www.sun.rhbnc.ac.uk/~uhap057/LTWeb/Absolute.html

It can never be at absolute zero. Basically, the reason is that in order to cool something down, you have to have an object that is colder, to move the heat to. As it is (by definition) impossible to get colder than absolute zero, it can never be reached.

Temperature is a measure of the energy of motion of particles of matter (approximate defintion). Absolute zero is defined by a state where the basic matter particles have no motion and hence no energy of motion. I have heard the opinion expressed that even the motion of electrons would have to cease to reach absolute zero, but I do not know if this is minority speculation or concensus. I also doubt this could be verified without controversy. It may not be possible to cool matter to absolute zero. The temperature of perfect vacuum would theortetically be absolute zero because there is no matter to have motion energy, but it is believed that even in intergalactic space there are hydrogen atoms bouncing around with some energy. They can't really settle down because there is background radiation and other energy passing through that vacuum so if you tried to measure the energy level in the vacuum, you would end up seeing something... You do not need something colder than absolute zero to use as a heat sink to get there. You need some means of extracting energy from the atoms and molecules. Theoretically you could use a magnitic or electric field that adjusts constantly to stop the motion of particles. Or perhaps shooting electrons "head-on" at things to slow them down. It might be like stopping a moving, spinning spacecraft by bouncing tennis balls off the faces that are moving/spinning toward you. Neither you nor your tennis balls have to be standing still to get the thing to stop. I don't believe we can measure atoms and molecules fast or accurately enough nor shoot electrons accurately enough to do this, but I don't see any mechanical or physical reasons why it should not be possible.

Temperature measures comparative energy per molecule of a substance. You can choose a temperature scale such that zero temperature means zero energy per molecule. The Kelvin scale is an example. "Absolute zero" is 0 Kelvin or -273.15°Celsius. (and these two scales increase at the same rate, so that 273.15 K is 0°C) Quantum mechanical effects prevent the energy from becoming exactly zero: there is always a residual energy which cannot be extracted, but modern experiments have approached very close. Silver nuclei have been cooled to 280 pK at the Helsinki University of Technology, Finland (a pK, or "picokelvin", is one millionth of one millionth of a Kelvin)

As the temperature decreases, the pressure of a gas also decreases. When a graph is drawn with temperature in celcius scale on x-axis and pressure of the gas on y-axis,it will be a straight line which when extended touches the temperature axis at -273.16 celcius which is called ABSOLUTE TEMPERATURE. Here,the graph is drawn for limited number of temperatures and extended to give the absolute temperature.But some scientists believe that the graph is a straight line upto a certain temperature and it changes it's slope after that temperature. So its value may be even lesser than -273.16 celcius. It has never been achieved before. But scientists are reaching nearer to it.

Absolute zerro is the tempature where all molecular motion stops. The coldest place in the universe is in Cornell University (and now many others colleges) where lasers are being used to trap atoms. The atoms are being held motinless in a gas . A Nobel prize was awarded to Caral W. for developing this technique. Albert Einstein ( finger in every pie) predicted a property for matter at these low tempatures . (A few thousands from absolute zerro). Free space is a hot-bed compared to the tempatures in these trapped (Rubudium) gass. But Hey, what do I know