1. Halley's comet orbits the sun roughly once every 76 years. It comes very close to the surface of the sun on its closest approach. Roughly how far our from the sun is it at its closest? Is it still 'in' the solar system? What planet's orbit is nearest when it is out there? [Hint: the mean distance in Kepler's third law is 1/2 the sum of the nearest and farthest distance from the sun. 2. (T1/T2)^2 = (R1/R2)^3 Any help is appreciated.