Together they constitute the "visual spectrum" (or "optical spectrum") because it is the part of the full spectrum that is seen with the human eye.
Stand outdoors to see and feel the radiation pouring from the Sun.
If with superhuman eyes you could see beyond red, you would encounter the "infrared" -- felt as heat on the skin -- which would merge gradually into the familiar "radio" portion of the spectrum.
I have integrated this web page on human evolution into an electronic text, " Nature's Holism - Holism.
A few examples of such lies are presented at the very bottom of this page.
For each dating or chronological method there is a link in the box at right to take you to that section of this page.
Buffon's Iron Sphere Experiments- On the basis of iron sphere cooling experiments, Frenchman Georges de Buffon estimated that the Earth would have needed 75,000 years to cool to its present temperature.
The quantitative approach is admirable, but Buffon's assumptions are flawed. Silicate minerals have lower heat conductivity than steels and are better insulators leading to slower cooling rates.