CLOSE
Original image
ThinkStock

Has a U.S. River Run Backwards Before?

Original image
ThinkStock

The ongoing drought conditions wreaking havoc across large swaths of the country have driven the water in Lake Michigan an inch below its previous record low, and aren’t stopping. Last month, the U.S. Army Corps of Engineers announced that, if this continues and the lake water drops below the level of the Chicago River, the river could reverse course and begin flowing back towards its source. (Thankfully, there’s a series of locks separating the two, which will help prevent the less-than-clean river from flowing into the lake and the city’s source of drinking water.) Has an American river ever done an about-face like this before?

Right Back Where it Started From

Oh yeah. In fact, the Chicago has done it before. If the river does reverse course, it won’t be running backwards so much as running forwards again. 

When Europeans first settled in the Chicago area, the river drained into Lake Michigan, which was fine—except that settlers used the river to dump waste, and used the lake for drinking water. As the city grew, there were numerous outbreaks of typhoid and cholera because of contaminated drinking water, and something had to be done. 

In the late 1800s, the city decided to solve their problem with an ambitious engineering feat: They would reverse the flow of the river and send it away from the lake and towards the Mississippi River. The so-called “Chicago Diversion” worked: It not only diverted contaminated water away from the city’s drinking water, but also connected the Great Lakes and Mississippi River water systems and opened up the possibility of commercial travel and trade between them. 

It hasn't been just barges and haulers that could cross from one system to the other, though. Invasive Asian carp, introduced decades ago to southern fish farms as pond cleaners, have gradually made their way north, threatening native species and altering food webs as they go. With the fish nearing the Great Lakes, the idea of un-reversing (re-reversing?) the Chicago River has been kicked around, but now it looks like the river could take care of the problem itself. 

All Shook Up

The most famous of American Rivers, the mighty Mississippi, also might have gone backwards more than once. In 1811 and 1812, three earthquakes—the most powerful to ever hit the eastern U.S.—struck what was then a sparsely populated area of the Louisiana Territory. 

Eyewitness accounts from the quake read like Michael Bay scripts: The ground rippled and quivered; chasms opened up and swallowed livestock and wagons; sand and dirt exploded from the ground like volcanic eruptions and blotted out the sun; the Mississippi shook with such violence that the water ran backwards and boats were dragged upstream. 

One boatman, wanting to get away from the trees falling over on the river banks, put his boat out into the middle of the river and soon found, he claimed, that “the current changed, and the boat hurried up, for about the space of a minute, with the velocity of the swiftest horse,” fast enough that he had to hold on to his hat to keep it on his head. 

Gradually, the man said, the river returned to its normal course. Exactly how long that took is unclear, and various firsthand accounts have the river going backwards for anywhere from a few hours to a few days. Whether the river even reversed itself at all is questionable, and the United States Geological Survey says that ground uplifts and waves moving upstream may have just created the illusion that the water was moving backwards. 

What’s more certain is that the Mississippi reversed course for about 24 hours when Hurricane Isaac struck last year, and when Hurricane Katrina hit in 2005.

Original image
iStock
arrow
Big Questions
What is Duck Sauce?
Original image
A plate of Chinese takeout with egg rolls and duck sauce
iStock

We know that our favorite Chinese takeout is not really authentically Chinese, but more of an Americanized series of menu options very loosely derived from overseas inspiration. (Chinese citizens probably wouldn’t recognize chop suey or orange-glazed chicken, and fortune cookies are of Japanese origin.) It would also be unusual for "real" Chinese meals to be accompanied by a generous amount of sauce packets.

Here in the U.S., these condiments are a staple of Chinese takeout. But one in particular—“duck sauce”—doesn’t really offer a lot of information about itself. What exactly is it that we’re pouring over our egg rolls?

Smithsonian.com conducted a sauce-related investigation and made an interesting discovery, particularly if you’re not prone to sampling Chinese takeout when traveling cross-country. On the East Coast, duck sauce is similar to sweet-and-sour sauce, only fruitier; in New England, it’s brown, chunky, and served on tables; and on the West Coast, it’s almost unheard of.

While the name can describe different sauces, associating it with duck probably stems from the fact that the popular Chinese dish Peking duck is typically served with a soybean-based sauce. When dishes began to be imported to the States, the Americanization of the food involved creating a sweeter alternative using apricots that was dubbed duck sauce. (In New England, using applesauce and molasses was more common.)

But why isn’t it easily found on the West Coast? Many sauce companies are based in New York and were in operation after Chinese food had already gained a foothold in California. Attempts to expand didn’t go well, and so Chinese food aficionados will experience slightly different tastes depending on their geography. But regardless of where they are, or whether they're using the condiment as a dipping sauce for their egg rolls or a dressing for their duck, diners can rest assured that no ducks were harmed in the making of their duck sauce.

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

Original image
arrow
Big Questions
Can You Really Go Blind Staring at a Solar Eclipse?
Original image

A total solar eclipse will cut a path of totality across the United States on August 21, and eclipse mania is gripping the country. Should the wide-eyed and unprotected hazard a peek at this rare phenomenon?

NASA doesn't advise it. The truth is, a quick glance at a solar eclipse won't leave you blind. But you're not doing your peepers any favors. As NASA explains, even when 99 percent of the sun's surface is covered, the 1 percent that sneaks out around the edges is enough to damage the rod and cone cells in your retinas. As this light and radiation flood into the eye, the retina becomes trapped in a sort of solar cooker that scorches its tissue. And because your retinas don't have any pain receptors, your eyes have no way of warning you to stop.

The good news for astronomy enthusiasts is that there are ways to safely view a solar eclipse. A pair of NASA-approved eclipse glasses will block the retina-frying rays, but sunglasses or any other kind of smoked lenses cannot. (The editors at MrEclipse.com, an eclipse watchers' fan site, put shades in the "eye suicide" category.) NASA also suggests watching the eclipse indirectly through a pinhole projector, or through binoculars or a telescope fitted with special solar filters.

While it's safe to take a quick, unfiltered peek at the sun in the brief totality of a total solar eclipse, doing so during the partial phases—when the Moon is not completely covering the Sun—is much riskier.

WOULDN'T IT BE EASIER TO JUST TELL YOUR KIDS THEY WILL GO BLIND?

NASA's website tackled this question. Their short answer: that could ruin their lives.

"A student who heeds warnings from teachers and other authorities not to view the eclipse because of the danger to vision, and learns later that other students did see it safely, may feel cheated out of the experience. Having now learned that the authority figure was wrong on one occasion, how is this student going to react when other health-related advice about drugs, alcohol, AIDS, or smoking is given[?]"

This story was originally published in 2012.

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios