Physicists from Germany have recently conducted an experiment where they achieved a temperature measuring 38 trillionths of a degree above absolute zero, making it the coldest temperature ever recorded on Earth.
As reported by NewAtlas, this totally different experiment had specific processes which involved dropping quantum gas and applying a magnetic field by switching it on and off, so as to make its atoms complete standstill.
Absolute zero (-273.15 °C or -459.67 °F) is the only possible coldest temperature on the thermodynamic scale and is the point where there’s no atomic motion or heat at all. However, scientists can’t achieve that mark as it is not possible to displace all kinetic energy from atoms in a system (for now).
However, a team of German scientists has now achieved a temperature of just 38 picoKelvin or 38 trillionths or 0.038 billionths of a degree above absolute zero. To achieve this extremely chilly feat, the team began with a cloud of 100,000 rubidium atoms placed in a vacuum chamber with a magnetic field to trap it.
Then it is made to cool down from a quantum gas called a Bose-Einstein Condensate (BEC), where atoms respond like a complete one big atom, due to which weird and unknown quantum effects can be seen on the macro scale. The team observed two billionths of a degree above absolute zero but that was not cold enough.
So, the team started the experiment at the Bremen Drop Tower research facility, where they dropped the BEC trap from 120m (393.7 ft). In the period of this free fall, the team continuously switched magnetic fields on and off. When the magnetic field is off, gas begins to expand, and the magnetic field switches on, and the gas contracts forcefully.
This switching process slows the expansion of gas almost to a complete halt and also diminishes this molecular speed effectively reducing the temperature.
The experiment achieved this coldest temperature ever recorded for only two seconds. But later it was observed that it can be maintained for up to 17 seconds in a weightless environment.