Small particles might be blown out of solar systems by the radiation pressure of sunlight. Assume that the particles are spherical with a radius r and a density of 0.5 g/cm3 and that they absorb all of the radiation in a crosssectional area of r2. The particles are a distance R from the Sun, which has a power output of 3.8 × 10Y^26 W. The speed of light is 3×10^8 m/s, the mass of the Sun is 1.99 × 1030 kg, and the gravitational constant is 6.67 × 10-11 N · m2/kg2
What is the radius r for which the radiation force of repulsion just balances the gravitational force of attraction to the sun?