Why do the solar and lunar calendars have a similar number of days each month?

Is this an open miracle?

Depends how one defines open miracle, I suppose, but there are historic reasons, rather than just astronomic. Unless it's an open miracle that a solar year in days is almost divisible by twelve and if "close" counts not only in horseshoes but also in open miracles.

Huh? They don't!

The earth takes around 365 days to go around the sun.

The mon takes around 29 days to go around the earth.

Isn't it amazing that 365/26 is close to 12 months a year, so the lunar and solar calendars basically fit together, and the year covers the four seasons exactly?

Can someone clearly explain cause and effect here?

beautiful design is always awe inspiring.
and universal language is mathematics, which is where you'll garner understanding.

The lunar calendar doesn't fit to the solar calendar. If you take 12 synodical months, it almost fits. Close, but in astronomical terms, it's an astronomical difference. That's why the lunar calendar, even if you take 12 lunar months, is so far off from the solar calendar. Take for example the Hebrew calendar, which lunarly speaking is either 353-355 or 383-385 days. Even being off by 9 days, which is the smallest gap, is enormous. In a very short time, you're already off by a month, and the gap just keeps on getting bigger until you jump through hoops to make up for it. And even the corrected Jewish calendar is way off from the solar calendar, such that in the absence of the Sanhedrin, even the corrected Jewish calendar is off by by weeks, and Pesach continues to drift away from Tekufat Nissan, contrary to what the OPS may tell you. Right now Pesach always continues to be in tekufat nissan, but that's only because the definitions keep changing. And it's way off from the real vernal equinox.
In short, they do not fit together. Not in any way, shape or form, unless you jump through all sorts of artificial hoops to make the square peg fit in the round hole, and even then, there is no extant calendar of a major religion where there isn't drift over time.
ANd if you're talking about the secular civil calendar, then the analogy is to finding an arrow in a tree, drawing a circle around it, and exlaiming on the bullseye. Because they worked backwards starting from a solar year, and dividing it into units of lunar months, but it was way off by days, so they made each month one or two days longer. That is not being close. That is using a coincidence and making it fit artificially.

Thank you.

Google tells me that tekufat Nissan is the same thing as the vernal equinox, but you're saying that it's supposed to be the same thing but doesn't fall out on the same day any more? Is tekufat Nissan a season or a day?

In short, the solar year is 365.25 days, almost. So they just divided it by the days in a lunar month, came up with twelve, with a bunch of days left over. It's not close.


There are two types of "tekufat nissan", and you only know which you are talking about contextually. Tekufat Nissan is the entire spring season. Tekufat nissan is also the halachic equinox, what we consider in halachah to be the vernal equinox [sort of like how we consider 72 minutes to be astronomically when 3 stars are visible, even though astronomically it isn't, but that's how we consider it for halachic purposes].

So really the season Tekufat Nissan starts at the moment of Tekufat Nissan and extends to the moment of Tekufat Tammuz, which is about 90 days or so.

Tekufat Nissan has a halachic definition, but it's usually around April 9. But that is about a three week drift from the astronomical vernal equinox which is in March.

Similarly Tekufat Tammuz has a halachic definition, and this year it was last week, about an hour after the start of yom shelishi, which was last Monday night.

But there are two "tekufot nissan" [and the other three tekufot as well]. The above is according to Shmuel but it's different according to R. Adda. But for purposes of halachah [or minhag], we generally follow Shmuel, the only exception being the calendar, since pesach [or more correctly, midday of 16 Nissan] has to fall after tekufat nissan according to R. Adda.

Cause: 365/29
Effect: 12 months in year.
Correct?

Thank you. A little confusing but it makes sense.

You're still off by at least ten days - a Jewish lunar year is at least ten days off from a Jewish solar year. If it divided evenly, it could be cool, but it doesn't. A Jewish lunar year is 355 days at best, and a solar year is 365.25 days (at least according to Shmuel; according to R. Adda a solar year is a little less). Yes, you can ignore the quarter day, divide 365 by an integer and get something sort of close to a lunar month that's off by just a day. But it ends there. And that day difference accumulates very quickly to a significant error over time.

Call me thick headed, but isn't the whole reason for a leap year percisely because they are NOT simelar ?

I see. Thank you.

Oh. Right.

A word for calendar junkies: Enneadecaeteris

How is that pronounced?

I don't know. Maybe someone who knows Greek would know
http://smg.photobucket.com/albums/v336/mel...t=enneadeca.jpg

But I think the first two parts are any-ad and de-ka, which are Greek for 9 and 10, or 19, as in the 19-year cycle [same as in the Jewish calendar where the leap years are on a 19-year cycle, since it is universally known that every 19 solar years is just about 235 lunar months].
I don't know what eteris means.