Talk:Solar sail

I'm apparently having difficulty with the wording of this bit:

The radiation pressure from the Sun against an absorbing sheet with a mass of 0.8 g/m² is equal to its weight with respect to the Sun's gravity, independent of its distance to the Sun. This mass/area ratio is doubled in the case of perfect reflection.

"doubled" in this case seems to mean that the radiation pressure from the Sun against a perfectly reflecting sheet of 1.6 g/m² is equal to its weight with respect to the Sun's gravity, whereas it should actually be 0.4 g/m² since reflecting photons gives twice the momentum that absorbing them would. So I changed it to "halved", and Patrick reverted with an explanation that seems to be in complete agreement with what led me to make the change in the first place. So I plead confusion. :) Bryan 00:45, 16 Sep 2004 (UTC)