Zero Kelvin is the lowest possible temperature in the thermodynamic temperature scale. It is equivalent to -273.15 degrees Celsius and is considered the point at which all thermal motion in a system stops.
In theory, yes, it is possible to achieve zero Kelvin in a system. However, it is nearly impossible to reach this temperature in practice due to the laws of thermodynamics.
If a system were to reach zero Kelvin, all thermal motion in the particles of the system would cease. This would lead to the complete absence of energy and a state of absolute stillness.
The potential effects of achieving zero Kelvin in a system are still largely unknown and are a topic of ongoing scientific research and speculation. It is hypothesized that at this temperature, quantum effects and phenomena such as superconductivity and superfluidity may occur.
No, achieving zero Kelvin is not necessary for most scientific experiments. Many experiments can be conducted at much higher temperatures, and the equipment and resources required to reach zero Kelvin are extremely complex and expensive.