Halley's comet travels faster as it approaches the sun, achieving speeds of approximately 40 miles per second. The velocity of the comet varies greatly due to its elliptical orbit.
Halley's comet takes 76 years to complete a single orbit. The velocity at which it travels varies depending on its distance from the sun. Halley's comet travels at its slowest speed once it has traveled to the point in its orbit farthest from the sun, a distance roughly as far away as Pluto. As it begins to fall back toward the inner solar system, Halley's comet begins to speed up due to the sun's increased gravitational pull.