how fast are comets
When they are very far away from the Sun, their speeds can be as low as a few kilometers per second. Close to the Sun, they can get well into the double-digits. At about 40-70 km/sec they are actually 'interstellar' because the Sun's escape speed is of this size, and the comets must be in hyperbolic orbits.Copyright 1997 Dr. Sten Odenwald Return to Ask the Astronomer.lose to the Sun, they can get well into the double-digits. At about 40-70 km/sec they are actually 'interstellar' because the Sun's escape speed is of this size, and the comets must be in hyperbolic orbits. Copyright 1997 Dr. Sten Odenwald Return to Ask the Astronomer.