The concept of a "lower temperature" that could cause the end of the universe is not well-defined in the current understanding of physics. The lower limit of temperature in the universe, as described by the Kelvin temperature scale, is absolute zero, which is 0 Kelvin (0 K) or approximately -273.15 degrees Celsius. At this temperature, the thermal motion of particles ceases, and no further decrease in temperature is possible.
Approaching absolute zero is not inherently dangerous, but it can have significant effects on certain materials and systems. As temperature decreases, various substances undergo changes in their physical properties. For example, materials may become more brittle, electrical conductivity may change, and phase transitions may occur. These effects can be harnessed in scientific and technological applications, such as in superconductors and cryogenics.
However, achieving temperatures very close to absolute zero requires sophisticated cooling techniques and specialized equipment. It is important to handle cryogenic substances and equipment with proper safety precautions, as extreme cold can cause injury, damage, or malfunction if not handled properly.
In summary, there is no defined "lower temperature" that could cause the end of the universe, and approaching absolute zero is not inherently dangerous but requires careful handling and specialized equipment.