Editing Absolute zero

[[Category: Physics]]
== Explanation ==
Absolute zero is the minimum theoretical temperature at which the entropy of a system reaches its minimum where most of the motion ceases. Or in other words, absolute zero is the lowest scale of [[temperature]] (0 K) where the [[internal energy]] of any system will be recorded at its minimum. It is impossible for a matter to reach zero energy state due to the quantum fluctuations that can be explained by the [[uncertainty principle|Heisenberg’s uncertainty principle]]. The system would still have [[zero-point energy]]. Hence, reaching absolute zero is not possible (Third law of thermodynamics).
== Frequently Asked Questions ==
=== Why can’t we reach absolute zero? ===
At absolute zero, any system would theoretically have minimum internal energy with the quantum zero-point energy in play, which makes it impossible for such a state to exist. Also, to transfer heat from one system to another, one would need a lower energy system (a heat sink) to transfer to. Such energy states don’t exist, making it impossible for reaching an absolute zero state.
=== What is the lowest temperature ever recorded? ===
As of July 2016, the record for the lowest temperature ever recorded by humans in a laboratory is around 0.45 nK in 2003 at MIT. The lowest naturally recorded temperature on Earth is around 184 K at Antarctica on July 21, 1983.
=== How cold is space? ===
2.7 K, which is the temperature of the [[cosmic microwave background|cosmic microwave background radiation]].
=== How zero-point energy affects reaching a zero energy state? ===
For a system to have zero energy, both its position and [[momentum]] will be zero. But uncertainty principle states that if the position of a particle is known accurately, then the momentum of the particle will not be known precisely. So for a system not to violate the uncertainty principle, it always has a minimum amount of energy. This minimum amount of energy is commonly known as the zero-point energy.