Pretty darn close, but it will be impossible to ever reach it.
Absolute zero is the lowest possible temperature in the universe. It’s defined as zero kelvin, or -273.15 degrees Celsius, or -459.67 degrees Fahrenheit.
At this point, atoms and molecules have no kinetic energy, meaning they can’t vibrate or move around.
They’re basically frozen in place.
But here’s the thing: absolute zero is impossible to reach in practice.
Why?
Because of the laws of thermodynamics, that’s why.
- The first law says that energy can’t be created or destroyed, only transformed.
- The second law says that entropy, or disorder, always increases in an isolated (closed) system.
- The third law says that entropy approaches a constant value as temperature approaches absolute zero.
If we cool something down to absolute zero, we need to remove all the heat from it.
But heat is a form of energy, and you can’t get rid of it completely. You can only transfer it somewhere else. And as you do that, you increase the entropy of the system, making it harder to reach the lowest possible entropy state.
Quantum physics also throws a wrench in the works.
You see, at very low temperatures, matter behaves in weird ways. It can exist in superposition, meaning it can be in two or more states at once.
It can also entangle with other particles, meaning they share information and properties across space and time.
These phenomena are called quantum effects, and they prevent matter from reaching a definite state at absolute zero.
So like I said earlier scientist have came close.
The current record holder is a team of researchers from MIT and Harvard who cooled a cloud of sodium atoms to 500 nanokelvin in 2023 .
That’s 0.0000005 kelvin, or -273.1499995 degrees Celsius, or -459.6699991 degrees Fahrenheit, colder than outer space.
But even at this ultra-low temperature, the atoms were still moving and interacting with each other through quantum effects.
They formed a state of matter called a Bose-Einstein condensate (BEC), where they acted like one giant super-atom with weird properties.
So they were not really at absolute zero, just very close to it.
