Here's why:
* Fahrenheit is not the standard scale for absolute zero. Absolute zero, the point where all molecular motion theoretically ceases, is defined on the Kelvin scale.
* -273 degrees Fahrenheit converts to -170 degrees Celsius. The actual temperature of absolute zero is -273.15 degrees Celsius, which is equivalent to 0 Kelvin.
So, while -273 degrees Fahrenheit is a very low temperature, it's still not quite cold enough to reach absolute zero.