The Sun's radiation peaks in the optical, at around 5000 A. People however, are much colder. Most of our thermal radiation is emitted as infrared radiation. Neutron Stars are strong X-ray emitters because they have extremely high temperatures.
In a MATHEMATICAL sense, the Stefan-Boltzmann Law looks like this:
By using this equation, we can determine just how
BRIGHT (in an absolute sense) the thermal object is, that is,
how many Watts / m2 of light (power) is coming from
this object. As the temperature INCREASES, the power INCREASES. But
it does so very rapidly: by the FOURTH power of the
temperature. As you turn UP the temperature even just a little bit on the
stove, it also gets much much brighter.
A few thought exercises:
- What is the temperature of your stove, if you can see it glowing at very, very red wavelengths (about 0.9 microns)? Do you really think its that hot?
- If I increase the stove to twice the temperature, how much brighter is the infrared light coming from it?