It's cold. Very cold. The coldest theoretical temperature is absolute zero on the Kelvin scale or -273.15 Celsius ( -459.67 Fahrenheit). At absolute zero all movement at the molecular level stops.* Empty space is believed to be on average 3 degrees Kelvin, so almost down to the coldest there is. You wouldn't want to go there without a jacket.

By comparison, the coldest natural temperature ever recorded on Earth was a balmy 184.00 Kelvin (-89.00C, -128.60F) in Vostok, Antarctica - July 21, 1983

However, recently scientists at CERN were able to get a section of the Large Hadron Collider (LHC) cooled to a chilly 1.9K. So that indeed is the coldest place we have ever measured.

The cold sector is 3.3 km long, and has over 200 of the big 2-in-1 superconducting dipole magnets in it. These are the magnets that will keep the particles going in a circle 27 km in circumference. This cooling operation has taken several months, starting in January 2008, with many successful checks and tests along the way.

During the first phase, the sector was cooled to around 80 K, slightly above the temperature of liquid nitrogen. As of 5 March, the teams were well into the second phase, cooling the sector to 4.5 K with the help of enormous refrigerators. The final phase, which began in mid-March, required a sophisticated pumping system in a bath of boiling helium that lowered the pressure to 15 millibars and cooled the magnets to 1.9 K. At this low temperature helium becomes superfluid, flowing with virtually no viscosity and allowing greater heat transfer capacity.

Story by Steven Hopstaken

*Okay, for you nick pickers out there, technically, absolute zero is physically unrealizable as matter possess quantum mechanical zero-point energy. It is theorized that at absolute zero all molecular motion does not cease, but does not have enough energy for transference to other systems, it is therefore correct to say that at 0 Kelvin molecular energy is minimal.

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