From a philosophical standpoint, how much energy is actually in one Joule is hard to determine. The way I see it is, we have trouble understanding what energy really is, so we reconcile that by using concepts like a Joule to be able to measure and calculate with.

Temperature is movement. Movement is frequency. Frequency generates heat. Heat is energy.
Frozen means no movement (frequency of vibration).
When things are freezing they are slowing down. When things are heating they are speeding up.
Science says the absolute lowest temperature that is theoretically possible is -273.15 C. That temperature is known as Absolute Zero (AZ).
We know Bosons exist. We know the Boson has a spin. If the Boson spins, it is moving. It is part of the Fermions of Matter.

Real Absolute Zero would be when even the spins of Fermions have stopped. Only then could matter be completely frozen. It may be at -1000 deg C or -273.18 C.
Any matter that has a cycle of movement cannot be AZ. If a particle of matter somewhere in the Universe cycles only once in 14 billion years it still has movement, thus has heat.

Imagine a Universe where every Fermion spin has stopped. All matter is at AZ. Nothing moves anywhere at any scale. It may remain that way forever or a split nanosecond.
Now, introduce movement to that. A Down Quark starts to spin.
At that point heat is generated, very little heat but heat all the same. That movement reacts with the frozen Fermions in its vicinity and starts more movement. Soon, the particle is moving, then the next and the next and so on. The reaction spreads in all directions faster and faster. It looks like an explosion, it grows hotter and hotter as the movement increases. We have ourselves a Big Bang, folks.
Eventually, all the matter that is moving will slow. As it slows, it cools. It continues to slow until all matter is once again at Absolute Zero. We have a Big Freeze, folks.

Science can't achieve True Absolute Zero because we are within a current expansion of movement of all matter. The thing about AZ that makes it so difficult to replicate is that we can't isolate a particle of matter from all movement. Even if we could, we would not be able to study the particle because to detect the particle it must move something to be detectable from nothing. Detection is isolating one thing from another. Imagine trying to detect a black dot in the middle of a black square.

On the human scale, Think about what happens when you see something. Light reflects off the item and enters your eyes. When a photon strikes a particle it is absorbed and reflected. The frequencies of light that are absorbed causes heat in the particle. The frequencies that are reflected cause movement in the particle that translates to heat. (Think Solar Sail, yes light can affect matter)

Science has transported a particle quantumly. So, even quantumly, matter has movement. AZ also includes frequencies quantumly affected. Which means, To achieve AZ, the quantum properties of the particle must also be controlled. Does the Spin of a W Boson also have a quantum state?

This brings me to Energy. The spin of Fermions requires energy to make it move. Is energy heat? Energy generates heat by moving matter. Heat is a product of Energy. It is theorized that there is such a thing known as Vacuum Energy or Zero Point Energy (ZPE).

ZPE implies that in a true vacuum, energy erupts into matter and antimatter that annihilate each other in a constant percolation of minute explosions both structurally and quantumly. When the annihilation is not completed, a particle and antiparticle are created. Those particles and antiparticles drift in the vacuum until they meet another, then bond or annihilate. When they bond, over time, they bond with more particles and eventually dust is formed. The gathering process continues, creating all matter in the Universe.

To achieve Absolute Zero with any particle, even the ZPE will need to be isolated from the particle both actually and quantumly.
When the Universe ends for this phase, all Energy, Including the ZPE will cease to affect matter. All matter in the Universe will stop moving until ...something...causes a movement. Then it will explode into a new Universe of movement for a time.

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