There are more precise and fussy calculations, but the broad truth of things is this: In a rare treat, the Jewish month of Kislev is kissing Ramadan, the holy month of the Islamic calendar, this year--both have joined hands with the sighting of the new moon, around which both the Jewish and Muslim calendars revolve. December, and therefore Christmas, is also falling under the twin moons of Ramadan and Kislev. Kwanzaa is, too; and the first night of Hanukkah will begin the same day (December 21) as the Winter Solstice, a modern pagan holiday.

So there are wonderful coincidences. When Muslims complete their fast of Ramadan with the feast of Eid ul-Fitr, African-Americans who celebrate Kwanzaa will be observing their first day, and Jews will be lighting candles for the sixth night of Hanukkah. And it will be the day after Christmas. Christmas, Ramadan, Hanukkah, and Kwanzaa all overlap in a complicated dance of light and darkness, sun and moon. To add to the spectacle, on December 25, a rare partial solar eclipse will be visible, if the skies are clear, from nearly all regions of North America. A solar eclipse won't happen again on Christmas Day for more than three centuries.

The calendars of the three major Western religions, Judaism, Christianity, and Islam, have their amazing synchronicities and strange calculations (strange each to each). They differ on how they calculate time: The Christian and secular calendar is purely solar; the Islamic calendar is purely lunar; the Jewish calendar splits the difference--it is lunar and solar, or lunisolar.

The traditions differ on when a day begins (sunset to Jews and Muslims, midnight to Christians and seculars). They differ when the month begins--the new moon for Jews and Muslims, and no moon or no care for the phases of the moon in the Christian and secular calendars.

They even have the most extraordinary tiny differences where you think they might be the same; thus, the Jewish month of Kislev and the Muslim month of Ramadan both begin at the time of the New Moon but not on the same day. That's for lots of complicated reasons having to do with both calendars--but an important one is that by decree of the Prophet Muhammad, Muslims rely on a sighting of the thinnest crescent of the new moon viewed after sunset before officially declaring that a month has begun. And that sighting occurs at least 15 hours after the actual "astronomical" new moon-- and may take longer depending on atmospheric conditions and where you do the sighting. (It's wonderful to look on a website and see photographs of the moon--that bare crescent, symbol of Islam, detected by the visible eye--barely visible amid reddish clouds and a pinpoint of Venus. My favorite is Khalid Shakaut's www.moonsighting.com.)

This year is rare, because the month of Ramadan has come to visit--so to speak--and it will not return to this exact configuration any time soon. The Islamic calendar is purely lunar, 12 months of alternating 29 and 30 days--a year that comes approximately 11 days short of the solar year. So the month of Ramadan will drift 11 days (or so) back toward November next year, and another 11 days the year after that, leaving the season of winter beyond, moving toward autumn, then summer, then spring.

It will be 33 years before Ramadan comes back to December again. But that year, Ramadan and Chanukah will miss Christmas by a whisker--Chanukah will end on Christmas Eve in 2033. It looks like we'll have to wait until 2065 for this triple overlap to occur once again.

Ramadan is not a fast that is tied to a particular season--it is a fast for all seasons. But Hanukkah and Christmas are clearly winter celebrations, and they share a coincidental number: 25. Christmas, at least the Western Christmas of Catholics and Protestants, falls on the 25th of December. Hanukkah falls on the 25th of Kislev.

This number too may not be entirely a coincidence. According to the Encyclopedia Judaica, Hanukkah was declared on the 25th of Kislev in remembrance of--and triumph over--the decree of Antiochus, the Greek Syrian ruler who desecrated the Temple of Jerusalem, thereby sparking the Maccabeean revolt. Some scholars speculate that that date was a pagan celebration--that Antiochus was imposing pagan rites on Jerusalem. The Maccabees turned that around and used the same date to commemorate their cleansing of the Temple and its rededication. (Hanukkah means "dedication.")

Other scholars believe that the 25th of December was also a pagan holiday. According to Britain's great monk the venerable Bede, it was "mother's night." Others believe it was a pagan festival known as the "sun's birthday"--the sun was understood to be born during the darkest days of the year. If so, then the celebration of the birth of the Son was instituted to replace the birthday of the Sun. That's something to think about in this year of solar eclipse Christmas-- which will make the darkness even darker.

People all over the world have long celebrated a holiday to mark the solstice, the shortest day of the year, when the sun seems to have gone away forever and must be coaxed back. Ancient Northern European pagans had Yule; modern pagans celebrate Winter Solstice. The truth is, after the winter solstice, we enter the darkest and longest nights of the year. It is a season where light is most valued, most cherished, most symbolic. And so it is natural in this season to make light, whether the colorful thick candles of Kwanzaa, the twirly candles of Hanukkah, or the bright lights of the Christmas tree.

Chanukah is designed calendrically to plumb the darkness and open toward the light. That's because it's an eight-day holiday that begins on the 25th day of a lunar month. So every Chanukah contains a new moon night, a night when the moon can't be seen. And in years like this one, when Chanukah comes after the winter solstice, that means that the "New Moon" night of Chanukah--this year the night of December 26th--is arguably "the darkest night of the year," since it is the longest night of the year that's not illuminated by the moon. The candlelighting comes in counterpoint to this celestial action.

The rabbinic sages once debated, as rabbinic sages will, about which way to light the Hanukkah candles. Should we start with eight candles and work our way down to one? Or should we start with one and work our way up to eight? The sterner school of Shammai argued that since the festival commemorated a miraculous jar of one day's worth of oil that somehow burned for eight days, therefore Hanukkah should begin with eight candles, and each day, as the oil burned down, one candle would be removed. That way, as the holiday was celebrated, we would experience by analogy the gradual diminishment of the miraculous jar of oil as it burned out. This was extremely logical and appealed to the head. But the merciful school of Hillel said that, no, during these long nights of winter, we cannot stand this. We must grow the light each night, brighter and brighter, from one candle to eight, logic or historical analogy aside.

Both schools were right, say other rabbis, only Shammai's way is the way of the world to come. In that world of perfection, the miraculous order will be revealed to us constantly, so we won't need to add candles to remind us of its presence when the sky is dark. But here in this world, we need all the physical light we can get to remind us of the spiritual light that secretly surrounds us, so Hillel's rule holds sway.

To Jewish mystics, Hanukkah is the season of the miraculous order. It is a season of miracles when in darkness a light was shown. Christians feel exactly the same way. And Ramadan is also the month of the revelation of the Qur'an. So, let us be mindful together, Jews, Christians, and Muslims, of the small miracles of sunset and crescent moons, of short days and long nights--and of the need to add some light of our own during these blessed days. And let us share that light with each other, friends and neighbors, from one tradition to another: Happy Hanukkah! Merry Christmas! Happy and Blessed Ramadan! Merry Solstice! Joyous Kwanzaa!