TORONTO – Scientists have broken a record for the coldest temperature ever recorded in a laboratory, achieving a trillionth of a trillionth of a degree below absolute zero by dropping the freezing, magnetic gas at the bottom of a 120-meter-tall tower.
The exact temperature scientists measured was 38 trillionth of a degree above -273 °C – the lowest ever measured in a laboratory to absolute zero.
Absolute zero in Kelvin, a temperature considered impossible for anything in the universe to reach, is -273.15 °C.
This feat was achieved when German researchers were aiming to study the wave properties of atoms to gain a better understanding of quantum mechanics, a discipline of science that examines how the world functions at the subatomic level. Where particles can exist in two places simultaneously.
Researchers from the Laboratory of the Center for Applied Space Technology and Microgravity at the University of Bremen created one of the “coldest places in the universe” for a few seconds. A German press release on the research.
Although no thermometer can actually measure that low temperature, scientists were able to calculate the number by observing the motion of the atoms in the newly-cooled gas. Temperature is actually a measure of the kinetic energy of the particles that make up an object or space, allowing researchers to calculate how cold the gas was.
Atoms and other particles have the unique property of acting in extremely strange ways in extremely low temperatures. In fact, extremely low temperatures can create what some call the fifth state of matter: a Bose–Einstein condensate (BEC), which occurs when a gas composed of bosons, a fundamental particle, cools to near absolute zero. is done.
At this temperature, these individual particles begin to act as a quantum entity with the same wave function, which was predicted by Albert Einstein nearly a century ago based on physicist Satyendra Nath Bose’s quantum formulation .
Studying BECs allows scientists to get a better picture of the behavior of subatomic particles.
The researchers used the Drop Tower at the University of Bremen – a microgravity lab where scientists use free fall to study objects at nearly weightlessness – to extend the duration of the BEC for longer than usual.
They gave off a magnetic field and as the BEC atoms collapsed to slow down, allowing the researchers to create the slowest diffusing BEC, and also the coolest yet.
According to the release, the slow expansion of the BEC allowed the researchers to observe it for up to two seconds.
The research is described in a paper published in Journal Physical Review Letters at the end of August.