Fun facts about leap year
2020 is a leap year, a 366-day-long year. Every four years, we add an extra day, February 29, to our calendars. These extra days – called leap days – help synchronize our human-created calendars with Earth’s orbit around the sun and the actual passing of the seasons. Why do we need them? Blame Earth’s orbit around the sun, which takes approximately 365.25 days. It’s that .25 that creates the need for a leap year every four years.
During non-leap years, aka common years – like 2019 – the calendar doesn’t take into account the extra quarter of a day actually required by Earth to complete a single orbit around the sun. In essence, the calendar year, which is a human artifact, is faster than the actual solar year, or year as defined by our planet’s motion through space.
Over time and without correction, the calendar year would drift away from the solar year and the drift would add up quickly. For example, without correction the calendar year would be off by about one day after four years. It’d be off by about 25 days after 100 years. You can see that, if even more time were to pass without the leap year as a calendar correction, eventually February would be a summer month in the Northern Hemisphere.
www.earthsky.org
