• Question: How fast can comet go ?

    Asked by gummy bear to Laurence on 7 Mar 2016.
    • Photo: Laurence O'Rourke

      Laurence O'Rourke answered on 7 Mar 2016:

      Great question gummy bear + great name. Let’s compare speed just to give you an idea of how fast it goes. I drive to work at about 100km/hr. A satellite needs to fly at 11km/sec (44000 km/hr) in order to fly to another planet and escape earths gravity. Rosetta’s comet was flying at about 55,000 km/hr when we landed Philae on it but when it got in its closest point to the sun it was flying at 120,000 km/hour. But why the increase in speed? Well when comets are far from the sun they are still pulled by the Suns gravity so they are slow, as they get closer to the sun in their orbit the pull is greater so they go faster. And that’s just our comet. Other comets fly faster if they have an orbit closer to the sun than Rosetta’s one.