Why Do Meteor Showers Return on the Same Dates Every Year? The Leonids Explained

Earth crosses the Leonid debris stream each November. The orbit explains the date, while the age and position of the dust help explain the spectacle. The comet need not be beside Earth for a grain to enter our atmosphere. Earth has its own orbit and takes about a year to return to the region where the two paths approach one another. The encounter sets the season of the shower. The amount of dust waiting at the crossing, the observer's location, the time of night and the condition of the sky help determine whether an individual sees a spectacle or spends half an hour looking at apparently motionless stars.