When did leap years start? Who was the wise guy who figured out that it takes the earth 365.25??? days to travel around the sun? And how can we even figure the exact amount of time it takes to do that today? When are leap seconds and minutes accounted for? Will our seasons ever shift because of innacuracies in these round numbers of ours?
I found all of the answers by searching for “leap year”.
Search? You mean I can search for things on the internet? WOW!! They should also make a feature like that for this message board. Wouldn’t it be cool if we could search the internet and this message board.
This was reviewed by SDSTAFF CKDextHavn in the “Cecil’s Mailbox” section: Why do we have Leap Years?
As whitetho’s link described, we’ll keep fudging the calendar to make it work out.
It’s interesting that our standard calendar divisions that are based on astronomical phenomena (day, month, year) are not evenly divisible into each other.
It’s not that hard to do. Notice, from Dex’s column, that it was pretty much all figured out in 1582. That’s BC, before computers. Not much light pollution back then. No yard lights, or neon signs, or auto dealer search lights, or mall parking lots. Most people slept, but there’s always a few weirdos who can’t sleep–and what else did they have to do?
You should do your own research but I’ll make a suggestion that doesn’t even require you to hit the search button on your browser; go outside and look at the night sky. That’s all it takes to figure out the calender. You don’t need fancy telescopes or optics. You will need to make several years of observations so it’s not considered cheating to use research that others have done.
If you take the time to do a little star gazing you’ll find that the constellations of the “fixed” stars changes over the course of the year. Yes, they rotate around the north star once every 24 hours but if you observer Orion or Ursa Major’s position at midnight then observer again about six months later at midnight you’ll find they are on the other side of the axis.
The rest is left as an exercise for the reader but note that 365.25 is only a close approximation. The corrected Gregorian calender skips one leap day three of every four centuries in the year ending in double zeroes. 1700, 1800 and 1900 were not leap years but 2000 is. That gets the calendar really close but IIRC there is an additional correction that doesn’t come around until the year 4000.
Joe, don’t think of it in mathematical terms. Just remember that the rotation of the earth (the act of turning 360 degrees on its axis) and the revolution of the earth (the act of revolving 360 degrees around the sun) are two independent events. The mistake is to think that there are cosmic clockworks that sync the rotation of the earth with its revolution around the sun.
So we have two measuring units: the amount of revolutions expressed in years, and the amount of rotations expressed in days. To be accurate, there are 365.2422 days (rotations) in a year (revolutions). Saying there are 365 days in a year is like saying there are 2.5 centimeters in an inch; while on a small scale the comparison of two different measuring units is close enough, the ratio falls apart on a larger scale. To say there are 365 X 16 days in 16 years is about 4 days off, but it’s pretty close. But over the course of 100 years, you’re going to be off almost a month.
Since seasons are determined by the position of the earth around the sun (a certain time of the year), the seasons won’t shift just because days don’t divide evenly into years. Especially since they’re not supposed to.
Hanson said:
Actually, that’s one of the reasons for the shift from Julian to Gregorian calendar. The problem is that when the count for the number of days does not correct for the small errors, the days (and associated months) shift with regard to the seasons.
It is clear to see if you use 365 days/year. In four years, the Solstices and equinoxes shift one day. In 20 years, that’s five days. It’s not because the seasons are moving, it’s because we’re short the extra little bit of day, so our counting gets off.
>> It’s interesting that our standard calendar divisions that are based on astronomical phenomena (day, month, year) are not evenly divisible into each other.
If I had been present at the time of the creation of the universe I would have arranged things to be much simpler and better arranged. Why don’t people know when to consult with me?
Well, if anyone ever DOES ask, I have a whole list of things I’d like to see done better in the next universe. Let’s start with humans. If we aren’t supposed to eat them, why are they made out of MEAT? And that whole pi thing. Why isn’t it just ‘3.0000000000000000000000000000’?
Don’t get me started.