In an underground laboratory in Italy, an international team of scientists has created the coldest cubic meter in the universe. The cooled chamber - roughly the size of a vending machine - was chilled to 6 milliKelvin or -273.144 degrees Celsius in preparation for a forthcoming experiment that will study neutrinos, ghostlike particles that could hold the key to the existence of matter around us. Read more
It may sound less likely than hell freezing over, but physicists have created an atomic gas with a sub-absolute-zero temperature for the first time. Their technique opens the door to generating negative-Kelvin materials and new quantum devices, and it could even help to solve a cosmological mystery. Read more
Ultracold science finds new method to get even colder
Researchers have developed a clever way to achieve the coldest temperatures ever recorded on Earth. Achieving such temperatures is necessary to study fundamental properties of matter and the strange effects caused by quantum mechanics. The new method relies on "optical lattices" of atoms from which only the hottest atoms are selectively removed. Read more
Chill things close to the lowest possible temperature and weird things start to happen. New Scientist takes a look at the coldest objects in the universe.
The curious things that happen at low temperatures keep on throwing up surprises. Last week, scientists reported that molecules in an ultra-cold gas can chemically react at distances up to 100 times greater than they can at room temperature. Read more
Absolute zero is the temperature at which entropy reaches its minimum value. As implied by the laws of thermodynamics, absolute zero cannot be reached by artificial or natural means because this would require a system to be fully removed from the rest of the universe. A system at theoretical absolute zero possesses quantum mechanical zero-point energy. Read more
By international agreement, absolute zero is defined as precisely 0 K on the Kelvin scale and as -273.15° on the Celsius scale.