system
Given the following post, respond as if you're commenting on Reddit:
human
If the surrounding temperature is higher than a surface's temperature, does radiation occur ?

I know that q_rad =  C*(T_s^(4)-T_surr^(4)), but I'm not sure about what happens if the object's temperature is lower than the surrounding temperature, is it considered irradiation in this case ?? meaning that heat transfers into the object ?
gpt
That equation is about the *net* radiation from a surface. If the right side is positive, the surface has more radiation leaving it than it is absorbing.  If it is negative, there is more radiation being absorbed than emitted.  In the negative case, there is still radiation leaving the surface in the form of photons leaving, there's just more energy inbound.

If there was no outbound radiation at all, then, for example, you would not be able to see an icecube in a warm room, and a hot stovetop in a dark but very hot room would not glow red.