Yes, in fact it's dependent on Temperature to the fourth power. More specifically it which depends on the emissivity of the surface, a perfect blackbody radiator has an emissivity 1.0, while highly polished gold has an emissivity of 0.02. The level of total energy transmission is directly proportional to the emissivity of the surface.The Annoyed Man wrote:Steve133 wrote: And my second question is: was I wrong in believing that, given temperatures high enough to radiate visible light, the steel of the barrel would dissipate that heat more rapidly than at lower temperatures where no visible light radiates? In other words, is the rate of heat dissipation constant, regardless of the temperature, or does it dissipate on a curve as it decreases?
List of emissivities: http://www.infrared-thermography.com/material.htm" onclick="window.open(this.href);return false;
The emissivity of a material not only dictates how much energy it radiates when heated, but also how much energy is absorbed with something hot is around it. Gold foil was used on the lunar landers as an insulation material since it would not absorb much heat from the much higher intensity solar radiation, but would also not emit heat as fast when the surface was facing the "coldness" of space.
This secondary part of the radiation equation is why a lot of infrared thermometers and most FLIR cameras aren't really accurate at telling you what the real temperature is, unles you can adjust the emissivity value to closely match the surface that you're measuring. (Yes, I have been known to look up the value for anodized aluminum and adjust the emissivity value in my infrared thermometer to get the most accurate temperature). Humans are around e=.98, which I always found interesting.