1. The problem statement, all variables and given/known data Halley’s Comet orbits the sun about every 75 years due to the gravitational force the sun provides. Compare the gravitational force between Halley’s Comet and the sun when the comet is at aphelion (its greatest distance from the sun) and d is about 4.5 x 10^12 m to the force at perihelion (or closest approach), where d is about 5.0 x 10^10 m. 2. Relevant equations F=GmM/d^2 (Not applicable because masses aren't provided?) 3. The attempt at a solution I wasn't sure where to begin considering the masses were not provided, but eventually I found that the distance from the sun at the furthest distance is 90x greater than when it is at its closest point. I then assumed that it wanted to me to use Newton's Law of Universal Gravitation that as the distance is doubled the force decreases by 1/4. But I'm not sure if where to go from here.