Haile's radius

Haile's radius is a measure of how far a heated object can radiate heat. To find out this haile's radius, an experiment is needed, and the name of the experiment is haile's experiment, and the research is like this: placing a hot object in a closed box and allowing the heat to emit through the air in the box until the end, and waiting for a certain time (this means the temperature of the object and the temperature of the air) (i.e. waiting a certain amount of time for it to equalize) but in this experiment the box does not necessarily have to emit heat.