You’re an astronomer studying the origin of the solar system, and you’re evaluating a hypothesis that sufficiently small particles were blown out of the solar system by the force of sunlight. To see how small such particles must be, compare the force of sunlight with the force of solar gravity, and solve for the particle radius at which the two are equal. Assume spherical particles with density 2 g/cm3 . Distance from the Sun doesn’t matter. Why not?