A solar year is the time it takes for the Earth to complete one full orbit around the Sun. This period is approximately 365.25 days long, which is why we have a leap year every four years to add an extra day in February. The concept of a solar year is essential for creating calendars, as it helps us track the changing seasons. The Gregorian calendar, widely used today, is based on this solar year, ensuring that our months align with the Earth's position relative to the Sun throughout the year.