How Many Dimensions Are There?

iStock
iStock

Ask someone to name every dimension they know of and they'll likely list the following: length, width, and depth. They might also add time if they’re thinking outside the three-dimensional box. But asking a string theorist, “How many dimensions are there?” would elicit a very different response. According to this branch of theoretical physics, there are at least 10 dimensions of space, most of which are impossible for humans to perceive.

Dimensions are the metrics that physicists use to describe reality. Sounds broad, right? Let's start with the three dimensions most people learn in grade school. The spatial dimensions—width, height, and depth—are the easiest to visualize. A horizontal line exists in one dimension because it only has length; a square is two-dimensional because it has length and width. Add depth and we get a cube, or a three-dimensional shape.

These three coordinates are used to pinpoint an object's location in space. But space isn’t the only plane we exist on; we also exist in time, which is where the fourth dimension comes in. Once we know a dot's altitude, longitude, latitude, and position in time, we have the tools needed to plot its existence in the universe as we know it.

But some physicists who subscribe to string theory argue there’s more to reality than the observable universe. String theory, also known as "superstring theory," aims to unify two main theories describing how the universe works: general relativity (which applies to very large objects) and quantum mechanics (which applies to very small ones). In a four-dimensional universe, this theory wouldn’t be possible, but once scientists tweaked the math to include 10 dimensions—11 including time—their equations worked.

After coming up with a theory that hinges on the existence of 10 space dimensions, string theorists then had the job of explaining where those new dimensions were hiding. Their answer: They are just as real as the "big" dimensions we can see, but the extra dimensions are curled up so tightly that they're too small for us to notice directly.

Our basic understanding of physics makes this hard to process, but string theorist Brian Greene does a great job of framing the concept in terms most people can understand. In his 2005 TED Talk, Greene compares these invisible dimensions to the cables connected to telephone poles: From a window, a wire looks like a one-dimensional line. But if we were to study it up close we'd see that the cord is actually round, making it three-dimensional. No analogy comparing unobservable dimensions to objects in the observable world can ever be perfect, but this illustrates how something so fundamental to reality could be hiding in plain sight.

String theory states there must be at least 10 dimensions of space plus one dimension for time, but there are physicists who argue that there are more. Some posit a universe composed of 11 space dimensions. But to really blow someone's mind when they ask how many dimensions there are, say 26: That's the magic number according to Bosonic string theory, and it's as high as mainstream physicists are willing to go for the time being.

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Looking to Downsize? You Can Buy a 5-Room DIY Cabin on Amazon for Less Than $33,000

Five rooms of one's own.
Five rooms of one's own.
Allwood/Amazon

If you’ve already mastered DIY houses for birds and dogs, maybe it’s time you built one for yourself.

As Simplemost reports, there are a number of house kits that you can order on Amazon, and the Allwood Avalon Cabin Kit is one of the quaintest—and, at $32,990, most affordable—options. The 540-square-foot structure has enough space for a kitchen, a bathroom, a bedroom, and a sitting room—and there’s an additional 218-square-foot loft with the potential to be the coziest reading nook of all time.

You can opt for three larger rooms if you're willing to skip the kitchen and bathroom.Allwood/Amazon

The construction process might not be a great idea for someone who’s never picked up a hammer, but you don’t need an architectural degree to tackle it. Step-by-step instructions and all materials are included, so it’s a little like a high-level IKEA project. According to the Amazon listing, it takes two adults about a week to complete. Since the Nordic wood walls are reinforced with steel rods, the house can withstand winds up to 120 mph, and you can pay an extra $1000 to upgrade from double-glass windows and doors to triple-glass for added fortification.

Sadly, the cool ceiling lamp is not included.Allwood/Amazon

Though everything you need for the shell of the house comes in the kit, you will need to purchase whatever goes inside it: toilet, shower, sink, stove, insulation, and all other furnishings. You can also customize the blueprint to fit your own plans for the space; maybe, for example, you’re going to use the house as a small event venue, and you’d rather have two or three large, airy rooms and no kitchen or bedroom.

Intrigued? Find out more here.

[h/t Simplemost]

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Who Was Jim Crow?

Wikimedia Commons, Public Domain
Wikimedia Commons, Public Domain

The name Jim Crow appears throughout many U.S. history books. It's used in reference to both the laws that segregated Black and white Americans in the Southern United States and the region itself during the period when these laws were enforced. Jim Crow Laws and the Jim Crow South were very real from the late 19th through the mid-20th centuries, but a real person named Jim Crow never existed. The name comes from a fictional character used to perpetuate racist stereotypes before the Civil War.

According to Ferris State University, a white performer named Thomas Dartmouth Rice originated the Jim Crow caricature in the 1830s. Rice, known as "the Father of Minstrelsy," would don blackface and affect an exaggerated African American dialect while performing his musical act. Jim Crow was meant to be a racist stereotype of an enslaved person: Like many minstrel personas that came after him, the character was portrayed as a clumsy buffoon.

Though Rice didn't invent minstrelsy, his success helped popularize the stage show format. Inspired by Rice, other minstrel actors borrowed his Jim Crow routine, and soon whites were using the name as a derogatory term for African Americans.

Even after slavery was abolished and minstrel shows faded into obscurity, the Jim Crow character lived on as a label. According to History, the first Jim Crow laws were passed in the Reconstruction Period as a way to limit the rights and resources of newly freed Blacks in the South. Such laws imposed literacy tests on Black voters, segregated public schools, and made it legal for businesses to segregate their customers by race.

How exactly these laws became associated with Jim Crow is unclear, but the phrase Jim Crow Laws was being used by the late 19th century. An 1892 article from The New York Times used the wording when reporting on Louisiana's segregated railroad cars.

Though most people may not be aware of the name's origins, Jim Crow still comes up today when discussing this dark period in U.S. history and its lasting effect on the country.

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