Answered by: James Kriz, Biology Undergrad, Wayne State College, Wayne, NE
The lowest POSSIBLE temperature is absolute zero, which defines 0 degrees Kelvin (-273.15
degrees C. or -459.67 degrees F.) If by 'nature' you mean ANYWHERE outside a laboratory,
intergalactic space would probably offer the lowest temperatures in the known Universe.
Temperature measures the average kinetic energy of any object's molecules or atoms. Since by
definition it contains no matter, the vacuum of space itself has NO temperature. Atoms,
molecules, and dust particles floating in in, however, would reach an equilibrium
temperature with the cosmic background radiation left over from the Big Bang. That has been
measured at a low of 2.724 K (-270.426 degrees C. or -454.767 degrees F.)
Answered by: Paul Walorski, B.A., Part-time Physics Instructor
'As long as men are free to ask what they must; free to say what they think; free to think what they will; freedom can never be lost and science can never regress. '