light

A few points that might be of general interest:

1. The dates: The date of Huygens' first written down material, which was orally presented to the French Academy of Sciences, is 1678---in contrast to the oft-quoted date of 1690. 1690 was the year of the first, French, publication of these notes (plus other material) in the form of a book.

Attached is an intriguing commentary on the scientific method through an example, written by my good friend, Luc Tartar. The specific example is that of trying to understand what 'light' might be, especially from a mathematician's point of view. The mathematician in this case is an extremely talented one, who also happens to actually understand a whole lot of physics and mechanics.

Via Physical Review Focus:

What you see is an optical fiber recoiling due to pulse of light flowing through it.  The abstract:

Phys. Rev. Lett. 101, 243601 (2008)

Observation of a Push Force on the End Face of a Nanometer Silica Filament Exerted by Outgoing Light