Meteor track. Time-exposure image of a night sky over trees showing a meteor track (a falling or shooting star) among many star trails. The meteor track is seen at lower centre, falling in a vertical plane. Falling stars are caused by tiny dust grains which enter Earth's atmosphere at speeds between 35 and 95 km/s; the air resistance incandesces the particles making them visible as streaks of light. By contrast, star trails are made by the movement of the stars through the sky as the Earth rotates. Different colours of the star trails reveal the variety of colours of the stars and their distances from the Earth.