Leap year 20223/23/2023 ![]() ![]() However - and this is an exception to the rule that came into effect in the year 2000 - if a year can be divided by 4 (leap year), 100 (not a leap year), but also 400, then it can be considered a leap year. In the Gregorian calendar, leap years are those that can be evenly divided by four - unless they can also be divided by 100, in which case they are not a leap year. The Gregorian calendar was then devised by Aloysius Lilius, an Italian astronomer and philosopher, (and named after Pope Gregory XIII) to replace the Julian calendar, with stricter criteria for leap years. Back then, leap years occurred every four years without fail. Leap years were introduced by that grand old Roman, Julius Caesar, in the Julian calendar. What's this about " almost " every four years? Leap years occur almost every four years, with some exceptions. Over time, the combination of common and leap years keeps us roughly in sync with the Earth's orbit of the sun. ![]() At 366 days, leap years are three-quarters of a day longer than a tropical year. Read more: A brief history of humanity's fascination for the summer solsticeĪ common year is 365 days, which is about a quarter of a day shorter than a tropical year. Failing to compensate for these "extra" hours would send us out of sync with the seasons - by about 24 days after only 100 years. So there's roughly a six-hour margin of error in every "common year." Leap years compensate for the extra 0.2422 of a day. That's 365 days, 5 hours, 48 minutes, and 46 seconds, or 365.2422 days to be precise. A true year - known as a tropical year, solar year, astronomical year or equinoctial year - is the time it takes the sun to pass from vernal (or spring) equinox to vernal equinox. ![]() We say it takes 365 days for the Earth to orbit the sun - but that's not strictly true. A calendar depicts a year, usually an imperfect year.Ī year is the time it takes for the Earth to orbit the sun. Read more: Stonehenge welcomes thousands for summer solstice It's an attempt at improving the accuracy of the Western-Christian calendar to keep it in sync with the Earth's rotations around the sun and "fixed" astronomical events, such as the equinoxes and solstices. In the Gregorian calendar, one of the most widely used calendars in the world, a common year is your standard "365-day" cycle. Hold on: what's the difference between a common year and a leap year? It seems fitting for a man who says he's "not interested" in birthdays that he should have the option of missing his three years out of (almost) every four.īut given my dad's talent for spinning yarns (he started his working life in markets), it's possible he wasn't even born in 1936, but in 1935, and that was just a bog-standard, "common" year. Family lore has it my father was born on Februa leap day in a leap year many moons ago. ![]()
0 Comments
Leave a Reply.AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |