Physics: why is it cold in space?
Self-tutoring about thermodynamics: the tutor imagines the temperature in space and why it’s meant to be so cold.
The temperature in space, away from any heat-producing features, is meant to be around 2.7K. By comparison, 0°C is 273K.
Temperature, as I’ve been taught since grade 10 physical science, is a measure of the kinetic energy of the resident particles. With no resident particles, how can one achieve a temperature? Moreover, why does “no temperature” mean “cold”?
A post at physics.stackexchange.com explains that an area’s temperature can be thought of as its impact on the temperature of a body that enters it. Therefore, space is cold because anything that enters it will radiate heat until it’s cold.
Source:Oracle Tutoring by Jack and Diane, Campbell River, BC.