> On Sat, May 28, 2011 at 2:16 PM, Mark Iverson > <zeropo...@charter.net> wrote: > > > > It is widely known that the 'rod' cells in the retina, which > > are responsible for seeing in low light levels, > > Indeed, a single photon can cause a rod cell to fire.
I read in some magazine article that in a test, a flaring match could be seen at 14 miles.
