Leap Year (2020, and more to come) – 90SS Ep. 6

Hello Everyone, and welcome back to 90ss, I’m Michael Tung I’ll be your host for today. Happy leap day everyone and assuming from the title and intro you already know we will be talking about leap year this month. On a “normal” year, there is 365 days, which because of the odd number results in every month having one more or less day in that month compared to the previous month (with the exception of August). However, how come in some years is there 366 days every 4 years. When the modern calendar was created, scientists had to round the number of days in a year, which happened to be rounding down to 365 days. Using dimensional analysis we can figure out that there should be 8760 hours in one year. However, in actuality, there are actually 8765 hours 48 minutes and 46 seconds in a year, making the calendar off by almost 6 hours. The calendar predicts that a year will happen faster than it actually will. You many think that the problem can be solved if we make each year 366 days but then the calendar would be off by 19 hours rather than 6 in the opposite direction. The solution that was created was the leap year. Add a day every 4 years to offset the faster time. However, adding it every 4 years is too often and will result it being at an error of 1 day per 100 years. To fix this problem, leap years on the century will be skipped (1900 was not a leap year). It’s better slightly too fast and will result in 1 day in 400 years. To fix this problem centuries divisible by 400 will be leap years. The error now is 1 day off in every 8,000 years which is good enough for most people.