Absolute Zero — A Wild Goose Chase?
Absolute Zero, or 0K on the Kelvin scale, is the theoretical lowest temperature matter can possibly reach. The curious reader may ask, is it possible for physicists to reach absolute zero? Alternatively, is this endeavor merely wild goose’s chase?
Temperature
Temperature is defined as the average kinetic energy of particles. Hotter objects have particles with higher speeds, while colder objects have particles with lower speeds. In other words, temperature and the average speed of particles are directly proportional.
The Kelvin Scale
The Kelvin Scale of Temperature is mostly used in the realm of science. In 1848, British mathematician and scientist William Thomson (aka Lord Kelvin) asserted that it was vital for the temperature scale to start at 0. Thus, the Kelvin Scale was created.
Absolute Zero
Absolute zero or 0K corresponds to -273.15°C, and is the lowest temperature that can be possibly achieved. That is, the particles in a substance at 0K are motionless, and can not be slowed down even further.
Fruitful Pursuit or Futile Efforts?
Unfortunately, absolute zero has been proven to be impossible to reach
Firstly, for something to cool down, thermal energy must be transferred to another system or object that is colder. That is, the hotter or faster moving particles need to collide with cooler particles and so that kinetic energy is lost and temperature decrease. Thus, In order to cool something to absolute zero it would have to be surrounded by something that is colder than absolute zero, which is impossible.
Nonetheless, scientists have came up with solutions to combat this problem. Laser cooling can decrease the temperature of objects without having them come in contact with a cooler object.
Breaking the Record
Nevertheless, determined scientists have strived to approach absolute zero. The closest to anyone has reached is around 150 nano Kelvin (150 x 10^-9 K). The 1997 Nobel Prize in Physics was awarded to the group which also proved the existence of the Bose-Einstein condensate.
In 2021, scientists just broke the record for the coldest temperature ever. These German scientists achieved the temperature of 38 trillionths of a degree above absolute zero by dropping magnetized gas 120 meters down a tower.
The world around us is filled with infinite possibilities, and nothing is definite. Perhaps physicists in the future can break the laws of thermodynamics and reach absolute zero. I look forward to learning about the new discoveries in physics.
