Shooting Star The visible phenomenon resulting from the dust and debris of asteroids and comets plunging into the atmosphere, transformed into high-temperature plasma by the intense frictional heat of ultra high speeds of up to ~144,000km/h. The majority of debris is microscopic, weighing less than a gram. Normally, they burn up without reaching the ground. Large pieces of debris heavier than 10g shine brightly like fireballs. When the orbit of the Earth intersects the trajectory of a passing comet, the huge amount of debris scattered in the wake of the comet pours down, causing a meteor shower.