Every summer Earth passes cosmic rubble from Comet Swift-Tuttle. Known as the Perseid meteor shower, (after constellation Perseus – radiant point in north-east skies) reigning champion of annual meteor events. Dependable, prolific Perseid rarely disappoints. Between July 17-August 24, Perseid teases summer nights with previews of the main event – peak performance of 60-100 meteors an hour between August 9-13.
Comet Swift-Tuttle circles the Sun in an oblong 133 year orbit. At perihelion (closest orbital point to the Sun, last reached in 1992 ) solar energy melts ice (primary mass of most comets ) releasing trapped space bits which join the comet’s tail. Extending hundreds of thousands Km, debris shadows Swift-Tuttle’s solar orbit. Perseid showers when Earth’s orbit intersects the outer edge of Swift-Tuttle’s tail. Every so often Jupiter’s gravitational influence stirs Swift-Tuttle’s tail – this year happens to be an “every so often” event.
Bill Cooke, head of NASA’s Meteoroid Environment Office announced Jupiter’s gravity pulled three streams of comet tail closer to Earth’s orbit, making 2016 the first time since 2009 Perseid watchers can anticipate an outburst of activity. Courtesy of Jupiter, instead of skimming Swift-Tuttle fringes we’ll pass through freshly tugged regions of space dust – projected meteors per hour will double to 200,
Perseids in Aug. 2015, a composite image by Petr Horalek of Kolonica, Slovakia [more]