"hot" end ...

Beyond the two ends we have infrared and ultraviolet. Infrared radiation converts easily to heat when absorbed by dark objects. I suspect this is what you're referring to, although as "light" it's invisible to the human eye. (Hmm. I guess you said that.)

Helicopters use infrared to observe the heat given off by living creatures on the ground.

Hi

But did I understand it correctly, namely that: It records images appearing at the "hot" end of the light spectrum.

Yes. You're right.

I shouldn't have said that infrared and ultraviolet are "beyond" the light spectrum. They're beyond the portion of the spectrum visible to the human eye. (Some animals can see it.)

Infrared radiation is not physically hot until it's absorbed by a dark object. (White tends to reflect it.) but it's correctly referred to as the hot end. It can sure give us

I think I understand. Thanks.

This graph shows how tiny the visible light band is compared to the infra red band:

http://www.lbl.gov/MicroWorlds/ALSTool/EMSpec/EMSpec2.html

Hi Avangi.

I've just checked the link you attached.

So is the "hot" end of the light spectrum invisible to the human eye at the end of this red band (where it's the reddest), close to this tiny yellow band where it's written "visible"? Is this the part the author was referring to by saying that it's the "hot" end of the light spectrum?

Yes, it is. It seems strange to speak of "invisible light," but that's exactly what ultra violet and infra red are. I guess it's just a matter of definition. (Ultra violet has some practical use in killing germs.)

Similarly, when we speak of "the speed of light," it applies to the entire electromagnetic spectrum, from radio waves to gamma rays, althought some of these waves are not co

Thanks for all the answer, Avangi. They were helpful.