Aerogel, Nanotechnology, Optics, Mathematics.
(Particle Size << 1/10 (λ)). In the case of silica aerogels, the most common light that enters the aerogel is sunlight, which has a wavelength of around 500 nanometers. 1/10 of 500 nanometers is around 50 nanometers, which perfectly matches our size of the aerogel particles, but remember, the size