This Friday, February 29th, 2008 is Leap Year! Leap Years are necessary because: It takes the Earth almost 6 hours longer than an even 365 days to complete one full orbit around the sun! To keep things in sync, the Roman astronomer Sosigenes suggested adding one whole day to the calendar every four years. Julius Caesar liked that idea so much that he decreed the new and improved Julian calendar beginning in 45 B.C. There have been several modifications and exceptions made over the years.