Q.  Does everything give out electromagnetic radiation?

A.  Yes. And its wavelength varies with the temperature of the thing emitting.

Q.  For example?

A.  Very hot stars emit light of short wavelength, such as blue, cooler stars emit light of longer wavelength, such as red. Cooler objects, such as people, emit at infrared wavelengths, perceived as heat.

Q.  How about planets and asteroids very distant from a sun?

A.  They emit at far infrared and microwave wavelengths.

Q.  For a given object, at a given temperature, is all its radiation at a fixed wavelength?

A.  No, the formulas give the peak temperature of a curve -- emissions at lower intensity spread out on either side of the peak.

Q.  If an object is emitting energy, why doesn't it get cooler?

A.  Because the object is also receiving emissions from the rest of the Universe. However, these are a mixture, not at a specific wavelength.

Q.  Where is there more on this?

A.  See P3: Living In The Universe .