Comet Halley moves about the sun in an elliptical orbit with its closest approach to the sun being about 0.590 AU and its greatest distance from the sun being 35.0 AU (1 AU = the average Earth-sun distance). If the comet's speed at closest approach is 51.0 km/s, what is its speed when it is farthest from the sun. The angular momentum of the comet about the sun is conserved because no torque acts on the comet. The gravitational force exerted by the sun on the comet has a moment arm of zero.