The graphs on the heating the robot page do not show this difference-we have made the scale of the intensity axis adjust itself for each temperature change, but you should be aware of this feature of blackbody radiation. The intensity difference between the peak of curve for the robot at 30,000 K and the peak of the curve for the robot at body temperature, is a factor of 10 billion-meaning, a star at 30,000 K puts out more energy by a factor of 10 billion than does a human at body temperature. So it is not easy to show both of these blackbody curves together on the same graph without using logarithms. This aspect of blackbody radiation will be highlighted in a forthcoming addition to Star Light, Star Bright. Electromagnetic radiation, or light, is a form of energy.
Visible light is a narrow range of wavelengths of the electromagnetic spectrum.
By measuring the wavelength or frequency of light coming from objects in the universe, we can learn something about their nature. Since we are not able to travel to a star or take samples from a galaxy, we must depend on electromagnetic radiation to carry information to us from distant objects in space. The human eye is sensitive to a very small range of wavelengths called visible light. However, most objects in the universe radiate at wavelengths that our eyes cannot see. Computer techniques then code the light into arbitrary colors that we CAN see.