An effect in which the observed radiants for meteors appear closer to the zenith than their true position. It occurs because meteoroids impacting on the upper atmosphere are subject to the Earth's gravitational pull, which increases their geocentric velocities. The change in apparent orbital velocity is most marked for slow meteoroids. The effect must be corrected for when analysing positional observations to determine meteor shower radiants and heliocentric orbits.
Subjects: Astronomy and Astrophysics.