All warm bodies emit electromagnetic radiation. Those, like the sun, that are extremely hot are incandescent and we can see them. Those bodies, like us, have a temperature close to 37 o
C emit only in the low infra-red region of the spectrum. The reason for this has to do with the physics relationship between temperature and radiation spectrum.
See: http://en.wikipedia.org/wiki/Black_body for some gory details.
Human eyes are pretty much insensitive to this kind of radiation. So, the answer to your question is no. However if you put 1000 people together in a room it could get very warm. A normal person emits about 100 Watts of heat.
Based on what you write, it sounds like if somehow you could get the light from all 10,000 people to come from the same direction, there would be just enough visible component to detect. However, the light comes in from different directions and lands on different parts on the retina and remins below threshold. Mike W.
(published on 07/26/09)