What is the temperature known as absolute zero expressed in Celsius?

Absolute zero is defined as the point at which the motion of atoms theoretically comes to a minimum, and it is considered the lowest possible temperature in the universe. This temperature is equivalent to -273.15 degrees Celsius.

In scientific terms, absolute zero is the point where the entropy of a perfect crystal approaches zero, effectively marking the end of thermal motion. When expressed in Celsius measurements, it is rounded to -273 degrees Celsius for simplicity in many contexts, which aligns perfectly with the provided answer.

This understanding is crucial in fields such as physics and chemistry, where temperature scales play a significant role in thermal dynamics and phase changes of matter. The other options represent temperatures that either do not correlate with the concept of absolute zero or are standard points of reference in Celsius that are much higher than absolute zero.