a comet orbit occurs usually once per 1000 years
short_period_comet is periodic_comet. periodic_comet is comet. comets has not set_orbits comets has set_orbits interstellar_comet is exosolar_comet. interstellar_comet is not exosolar_comet. long_period_comet is not periodic_comet. short_period_comet is not periodic_comet. periodic_comet is not comet. long_period_comet is periodic_comet.