The human eye can barely detect a star whose intensity at the earth's surface is \(1.6 \times 10^{-11} \mathrm{~W} / \mathrm{m}^{2}\). If the dark-adapted eye has a pupil diameter of \(7.0 \mathrm{~mm}\), how many photons per second enter the eye from the star? Assume the starlight has a wavelength of \(550 \mathrm{~nm}\).