This year, Hanukkah begins on the same day as Christmas is celebrated. If nobody steps in, we might someday celebrate Hanukkah with red, white and blue fireworks.
The reason for all this convergence? It’s because of calendars, wrote Ben Blatt for Slate the last time Hanukkah lined up with another holiday—2013, when it lined up with Thanksgiving. "The reason Hanukkah moves around the calendar so much has to do with the Earth’s orbit and the imperfections of our calendar systems," he writes. "It takes the Earth approximately 365 days, 5 hours and 48 minutes to orbit the sun." But the Gregorian Calendar used throughout most of the world doesn't work out to that exact length, and neither does the Hebrew Calendar.
These discrepancies mean that the summer solstice is slowly happening earlier and earlier in the Gregorian calendar. Over one million years, the solstice will occur earlier in June, then in May, then in April, eventually coming back to June 21. The Hebrew calendar only takes about 80,000 years to make the same journey, he wrote, which means “Jewish holidays are slowly revolving their way through the Gregorian Calendar.”
But it’s probable that lighting the menorah won’t coincide with planting an Arbor Day sapling anytime soon, he writes: Jewish laws about the time of year when certain holidays must be celebrated means that timekeepers will step in to restore order at some point.
Even if nothing is done, it will be almost 80,000 years before Thanksgivukkah happens again, Blatt writes. Christmas and Hanukkah happening at the same time, however, is a fairly frequent occurrence, writes Zachary Crockett for Vox. Since 1900, he writes, the first night of Hanukkah has been on Christmas Eve three times, making 2016 the fourth time. It has also started on Christmas Day four times over the same period. This is because Hanukkah always begins on the 25th night of the month of Kislev in the Hebrew calendar, he writes.
But although Hanukkah is usually associated with Christmas in the United States, writes Daniel Luzer for Pacific Standard, that fact is unusual in the Jewish world and even questioned by some. “The first major time that Hanukkah was celebrated in a Christmas-like manner was probably in America during the 1800s,” he writes. Around that same time, Christmas was also being re-invigorated as a holiday by department stores, and both holidays were used as a tactic to sell more.
“Many international Jews find this industry puzzling and see it as a contamination of Judaism,” he writes. One rabbi told him that Jews' “principal, focal time of year” should be on the new year, Rosh Hashanah, and Yom Kippur.
Which are also slowly revolving through the Gregorian calendar. Rosh Patrick’s Day, anyone?