CLOSE
ThinkStock
ThinkStock

Why is This The Last Time Hanukkah and Thanksgiving Will Occur on The Same Day?

ThinkStock
ThinkStock

We measure time by the way things rotate. It takes one day for the Earth to spin one full rotation on its own axis. It takes a little less than 28 days for the moon to rotate once around the Earth. It takes a little more than 365 days for the Earth to go around the sun. It would be nice if all this rotating was perfectly synced up, but it isn’t, and since we can’t control the motions of the planets, we are stuck with a messy calendar system that needs a bit of adjusting now and then.

Leap years are one way we correct for mismatches. Having months of varying lengths is another. In the calendar we use, the months are only roughly inspired by moon cycles. If we measured months by the moon and the year by the sun, the seasons would start to drift and eventually the Fourth of July would be in the dead of winter.

The Hebrew calendar, used to determine the dates of Jewish holidays, follows the cycles of the moon more closely. Months are 29 or 30 days, but complicated adjustments are made, including the addition of an extra month every so often, in order to ensure that certain holidays show up in the correct season. Hanukkah is supposed to start on the 25th of Kislev, which after drift and adjustment, ends up falling between the end of November and the end of December. This year it’s on November 28th, the earliest date it can be, which also happens to be Thanksgiving.

The 25th of Kislev will fall on November 28th again, but not when November 28th is also Thanksgiving (fourth Thursday of the month). Also, there is a tiny difference in the way adjustments to align the seasons are made in the two calendars, so tiny that they only matter after they accumulate for a few hundred years. By the time enough years have passed to get to the point where Hanukkah would fall on a November 28th that was also Thanksgiving again, that tiny divergence will have pushed Hanukkah over the line to the next day. And there’s no going back to the earlier date. The earliest date for Hanukkah will slowly keep getting later...

...unless another big adjustment by decree is made, which is what has happened every couple thousand years in the history of calendar keeping. If Hanukkah and Thanksgiving coincide again, it won’t be according to the systems as they are in place now, but through our improvised efforts to keep up with the sloppy, syncopated spinning of the spheres.

If you want more specific details on the adjustments, here is a more in-depth explanation of the numbers.

nextArticle.image_alt|e
iStock
arrow
Big Questions
What's the Difference Between Gophers and Groundhogs?
Gopher or groundhog? (If you chose gopher, you're correct.)
Gopher or groundhog? (If you chose gopher, you're correct.)
iStock

Gophers and groundhogs. Groundhogs and gophers. They're both deceptively cuddly woodland rodents that scurry through underground tunnels and chow down on plants. But whether you're a nature nerd, a Golden Gophers football fan, or planning a pre-spring trip to Punxsutawney, Pennsylvania, you might want to know the difference between groundhogs and gophers.

Despite their similar appearances and burrowing habits, groundhogs and gophers don't have a whole lot in common—they don't even belong to the same family. For example, gophers belong to the family Geomyidae, a group that includes pocket gophers (sometimes referred to as "true" gophers), kangaroo rats, and pocket mice.

Groundhogs, meanwhile, are members of the Sciuridae (meaning shadow-tail) family and belong to the genus Marmota. Marmots are diurnal ground squirrels, Daniel Blumstein, a UCLA biologist and marmot expert, tells Mental Floss. "There are 15 species of marmot, and groundhogs are one of them," he explains.

Science aside, there are plenty of other visible differences between the two animals. Gophers, for example, have hairless tails, protruding yellow or brownish teeth, and fur-lined cheek pockets for storing food—all traits that make them different from groundhogs. The feet of gophers are often pink, while groundhogs have brown or black feet. And while the tiny gopher tends to weigh around two or so pounds, groundhogs can grow to around 13 pounds.

While both types of rodent eat mostly vegetation, gophers prefer roots and tubers (much to the dismay of gardeners trying to plant new specimens), while groundhogs like vegetation and fruits. This means that the former animals rarely emerge from their burrows, while the latter are more commonly seen out and about.

Groundhogs "have burrows underground they use for safety, and they hibernate in their burrows," Blumstein says. "They're active during the day above ground, eating a variety of plants and running back to their burrows to safety. If it's too hot, they'll go back into their burrow. If the weather gets crappy, they'll go back into their burrow during the day as well."

But that doesn't necessarily mean that gophers are the more reclusive of the two, as groundhogs famously hibernate during the winter. Gophers, on the other hand, remain active—and wreck lawns—year-round.

"What's really interesting is if you go to a place where there's gophers, in the spring, what you'll see are what is called eskers," or winding mounds of soil, Blumstein says [PDF]. "Basically, they dig all winter long through the earth, but then they tunnel through snow, and they leave dirt in these snow tunnels."

If all this rodent talk has you now thinking about woodchucks and other woodland creatures, know that groundhogs have plenty of nicknames, including "whistle-pig" and "woodchuck," while the only nicknames for gophers appear to be bitter monikers coined by Wisconsin Badgers fans.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

nextArticle.image_alt|e
iStock
arrow
Big Questions
Why Does Santa Claus Give Coal to Bad Kids?
iStock
iStock

The tradition of giving misbehaving children lumps of fossil fuel predates the Santa we know, and is also associated with St. Nicholas, Sinterklaas, and Italy’s La Befana. Though there doesn't seem to be one specific legend or history about any of these figures that gives a concrete reason for doling out coal specifically, the common thread between all of them seems to be convenience.

Santa and La Befana both get into people’s homes via the fireplace chimney and leave gifts in stockings hung from the mantel. Sinterklaas’s controversial assistant, Black Pete, also comes down the chimney and places gifts in shoes left out near the fireplace. St. Nick used to come in the window, and then switched to the chimney when they became common in Europe. Like Sinterklaas, his presents are traditionally slipped into shoes sitting by the fire.

So, let’s step into the speculation zone: All of these characters are tied to the fireplace. When filling the stockings or the shoes, the holiday gift givers sometimes run into a kid who doesn’t deserve a present. So to send a message and encourage better behavior next year, they leave something less desirable than the usual toys, money, or candy—and the fireplace would seem to make an easy and obvious source of non-presents. All the individual would need to do is reach down into the fireplace and grab a lump of coal. (While many people think of fireplaces burning wood logs, coal-fired ones were very common during the 19th and early 20th centuries, which is when the American Santa mythos was being established.)

That said, with the exception of Santa, none of these characters limits himself to coal when it comes to bad kids. They’ve also been said to leave bundles of twigs, bags of salt, garlic, and onions, which suggests that they’re less reluctant than Santa to haul their bad kid gifts around all night in addition to the good presents.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios