The culture of the U.S. military is such that human enhancement is accepted as a goal, taking people beyond the norm. There are so many resources going into that kind of research.
Life evolved under conditions of light and darkness, light and then darkness. And so plants and animals developed their own internal clocks so that they would be ready for these changes in light. These are chemical clocks, and they're found in every known being that has two or more cells and in some that only have one cell.
Before the advent of artificial light, we had 13, 14 hours in bed every night... and so what we experience now is about a 40% contraction of how we used to sleep, and I for one am glad of that - I don't want to spend 13 hours in bed.
