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5 Strange Facts About the Planet Earth

by Alex Carter

You know what it’s like: You live somewhere all your life but never realize just how great it is until someone comes to visit. While it’s just a shame we don’t get any visitors to marvel at all the peculiarities of our home planet, here are five facts you might still appreciate.

1. EARTH'S A GIANT DYNAMO.

The core of the Earth is a solid lump of nickel and iron, rotating in a sea of molten iron and nickel. This rotation functions the same way winding up a hand-held generator does, giving Earth an enormous magnetic field that extends up to 50,000 kilometers out into space. This magnetic field is crucial for life on Earth, as without it we would be exposed to the full force of the Sun’s radiation. As well as causing cancers and other radiation-aggravated conditions, the radiation's sheer force would blow our atmosphere into space, as happened with Mercury, and to a lesser extent, Mars. Instead, charged particles are (mostly) harmlessly deflected away, giving rise to the auroras.

It’s not all good though: Any particles that hit the Earth head-on tend to get trapped in the field and can’t get out. These so-called Van Allen Radiation Belts can pose a hazard for astronauts who leave low Earth orbit.

2. IT'S THE DENSEST PLANET IN THE SOLAR SYSTEM.

While Earth may not be the biggest planet in the system, it is the biggest rocky planet in the solar system, and also the densest. Therefore, Earth has by far the highest surface gravity of any terrestrial object in the solar system. This is both a blessing and a curse.

The reason for the high density is the large deposits of heavy elements in the Earth’s makeup. Elements such as lead and uranium are much rarer on other worlds, which gives us a huge advantage in the amount and variety of construction materials available here on Earth. The high gravity has also demanded that humans develop the reflexes and endurance necessary to cope with such gravity, meaning we are far more durable than the potential delicately boned, sloth-like creature we could be had we evolved in low gravity.

Unfortunately, that high gravity makes Earth the worst place in the solar system for space exploration. The sheer cost of overcoming Earth’s gravity during every launch has been the single biggest barrier to space travel. To put it into perspective, if the Earth only had the same gravity as the Moon, a typical airplane would be fast enough to get into orbit. The human race might have explored much more of the solar system using present day technology if we had lower gravity—although, of course, the weakness of low-gravity humans might have proven to be an equal barrier.

3. THE MOON IS DISPROPORTIONATELY HUGE.

Most planets in the solar system have moons, and our moon may not be the biggest of them, but in comparison to Earth's size, it's enormous. Most scientists think that rather than coalescing on its own like the other large moons, it was violently shorn off Earth billions of years ago by a collision between Earth and another planet. The impact—with a planet about the size of Mars—liquified Earth in the heat, and the Moon broke off, gradually cooling into a ball of rock. New research suggests that not just one but multiple collisions may be responsible for its formation.

The Moon’s size and distance are a giant cosmic coincidence, allowing us on Earth's surface to experience total eclipses, annular eclipses, and partial eclipses, all from the comfort of our own planet. If the Moon were smaller or farther away, we wouldn't see any sort of eclipse at all.

The Moon is also an important tool for scientists trying to better understand Earth's composition. Starting with all the same raw materials, except for the magnetic field, the Moon cooled, geological activity stopped, and the solar wind blew away what atmosphere there was. Now, the surface is littered with craters which could not be healed, like scars. And the razor sharp soil sticks to everything, even the radiation coming in from the Sun. (Seems like we got the better end of that deal.)

4. WE LIVE ON A GIANT NUCLEAR FURNACE.

Take a spade to many points on the Earth’s crust and you might dig up a selection of radioactive elements. While we might think of the Earth’s magnetic field as protecting us from radiation, it does little to protect us from what’s right under our feet.

Most of the radioisotopes on Earth reside in the core, where the heat from their decay keeps the core molten, the tectonic plates moving, and the dynamo deep in the Earth rotating. If it weren’t for radioisotopes, the core would cool, the magnetic field would disappear, and the Earth would slowly become uninhabitable. There is another consequence of all these radioactive elements, though. In Oklo, Gabon, it was discovered that the uranium mines contained significantly less uranium-235 (the kind used in nuclear reactors and weapons) than the other isotopes. The startling conclusion was that the reserves had been used over millions of years in a naturally occurring nuclear reactor.

5. IT IS THE ONLY PLANET KNOWN TO HAVE LIFE.

Despite current attempts to find other habitable planets, Earth is the only place in the universe we can be sure that there is life. With liquid water, oxygen, and plenty of sunlight, we really lucked out. But with recent findings of water on Europa and Callisto, Jupiter's moons, we have new hope that someday we'll find another planet capable of supporting life.

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Animals
New Plankton Species Named After Sir David Attenborough Series Blue Planet
John Phillips, Getty Images for Tourism Australia
John Phillips, Getty Images for Tourism Australia

At least 19 creatures, both living and extinct, have been named after iconic British naturalist Sir David Attenborough. Now, for the first time, one of his documentary series will receive the same honor. As the BBC reports, a newly discovered phytoplankton shares its name with the award-winning BBC series Blue Planet.

The second half of the species' name, Syracosphaera azureaplaneta, is Latin for "blue planet," likely making it the first creature to derive its name from a television program. The single-cell organisms are just thousandths of a millimeter wide, thinner than a human hair, but their massive blooms on the ocean's surface can be seen from space. Called coccolithophores, the plankton serve as a food source for various marine life and are a vital marker scientists use to gauge the effects of climate change on the sea. The plankton's discovery, by researchers at University College London (UCL) and institutions in Spain and Japan, is detailed in a paper [PDF] published in the Journal of Nannoplankton Research.

"They are an essential element in the whole cycle of oxygen production and carbon dioxide and all the rest of it, and you mess about with this sort of thing, and the echoes and the reverberations and the consequences extend throughout the atmosphere," Attenborough said while accepting the honor at UCL.

The Blue Planet premiered in 2001 with eight episodes, each dedicated to a different part of the world's oceans. The series' success inspired a sequel series, Blue Planet II, that debuted on the BBC last year.

[h/t BBC]

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5 Ways You Do Complex Math in Your Head Without Realizing It
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The one thing that people who love math and people who hate math tend to agree on is this: You're only really doing math if you sit down and write formal equations. This idea is so widely embraced that to suggest otherwise is "to start a fight," says Maria Droujkova, math educator and founder of Natural Math, a site for kids and parents who want to incorporate math into their daily lives. Mathematicians cherish their formal proofs, considering them the best expression of their profession, while the anti-math don't believe that much of the math they studied in school applies to "real life."

But in reality, "we do an awful lot of things in our daily lives that are profoundly mathematical, but that may not look that way on the surface," Christopher Danielson, a Minnesota-based math educator and author of a number of books, including Common Core Math for Parents for Dummies, tells Mental Floss. Our mathematical thinking includes not just algebra or geometry, but trigonometry, calculus, probability, statistics, and any of the at least 60 types [PDF] of math out there. Here are five examples.

1. COOKING // ALGEBRA

Of all the maths, algebra seems to draw the most ire, with some people even writing entire books on why college students shouldn't have to endure it because, they claim, it holds the students back from graduating. But if you cook, you're likely doing algebra. When preparing a meal, you often have to think proportionally, and "reasoning with proportions is one of the cornerstones of algebraic thinking," Droujkova tells Mental Floss.

You're also thinking algebraically whenever you're adjusting a recipe, whether for a larger crowd or because you have to substitute or reduce ingredients. Say, for example, you want to make pancakes, but you only have two eggs left and the recipe calls for three. How much flour should you use when the original recipe calls for one cup? Since one cup is 8 ounces, you can figure this out using the following algebra equation: n/8 : 2/3.

algebraic equation illustrates adjustment of a recipe
Lucy Quintanilla

However, when thinking proportionally, you can just reason that since you have one-third less eggs, you should just use one-third less flour.

You're also doing that proportional thinking when you consider the cooking times of the various courses of your meal and plan accordingly so all the elements of your dinner are ready at the same time. For example, it will usually take three times as long to cook rice as it will a flattened chicken breast, so starting the rice first makes sense.

"People do mathematics in their own way," Droujkova says, "even if they cannot do it in a very formalized way."

2. LISTENING TO MUSIC // PATTERN THEORY AND SYMMETRY

woman enjoys listening to music in headphones
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The making of music involves many different types of math, from algebra and geometry to group theory and pattern theory and beyond, and a number of mathematicians (including Pythagoras and Galileo) and musicians have connected the two disciplines (Stravinsky claimed that music is "something like mathematical thinking").

But simply listening to music can make you think mathematically too. When you recognize a piece of music, you are identifying a pattern of sound. Patterns are a fundamental part of math; the branch known as pattern theory is applied to everything from statistics to machine learning.

Danielson, who teaches kids about patterns in his math classes, says figuring out the structure of a pattern is vital for understanding math at higher levels, so music is a great gateway: "If you're thinking about how two songs have similar beats, or time signatures, or you're creating harmonies, you're working on the structure of a pattern and doing some really important mathematical thinking along the way."

So maybe you weren't doing math on paper if you were debating with your friends about whether Tom Petty was right to sue Sam Smith in 2015 over "Stay With Me" sounding a lot like "I Won't Back Down," but you were still thinking mathematically when you compared the songs. And that earworm you can't get out of your head? It follows a pattern: intro, verse, chorus, bridge, end.

When you recognize these kinds of patterns, you're also recognizing symmetry (which in a pop song tends to involve the chorus and the hook, because both repeat). Symmetry [PDF] is the focus of group theory, but it's also key to geometry, algebra, and many other maths.

3. KNITTING AND CROCHETING // GEOMETRIC THINKING

six steps of crocheting a hyperbolic plane
Cheryl, Flickr // CC BY-SA 2.0

Droujkova, an avid crocheter, she says she is often intrigued by the very mathematical discussions fellow crafters have online about the best patterns for their projects, even if they will often insist they are awful at math or uninterested in it. And yet, such crafts cannot be done without geometric thinking: When you knit or crochet a hat, you're creating a half sphere, which follows a geometric formula.

Droujkova isn't the only math lover who has made the connection between geometry and crocheting. Cornell mathematician Daina Taimina found crocheting to be the perfect way to illustrate the geometry of a hyperbolic plane, or a surface that has a constant negative curvature, like a lettuce leaf. Hyperbolic geometry is also used in navigation apps, and explains why flat maps distort the size of landforms, making Greenland, for example, look far larger on most maps than it actually is.

4. PLAYING POOL // TRIGONOMETRY

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If you play billiards, pool, or snooker, it's very likely that you are using trigonometric reasoning. Sinking a ball into a pocket by using another ball involves understanding not just how to measure angles by sight but triangulation, which is the cornerstone of trigonometry. (Triangulation is a surprisingly accurate way to measure distance. Long before powered flight was possible, surveyors used triangulation to measure the heights of mountains from their bases and were off by only a matter of feet.)

In a 2010 paper [PDF], Louisiana mathematician Rick Mabry studied the trigonometry (and basic calculus) of pool, focusing on the straight-in shot. In a bar in Shreveport, Louisiana, he scribbled equations on napkins for each shot, and he calculated the most difficult straight-in shot of all. Most experienced pool players would say it’s one where the target ball is halfway between the pocket and the cue ball. But that, according to Mabry’s equations, turned out not to be true. The hardest shot of all had a surprising feature: The distance from the cue ball to the pocket was exactly 1.618 times the distance from the target ball to the pocket. That number is the golden ratio, which is found everywhere in nature—and, apparently, on pool tables.

Do you need to consider the golden ratio when deciding where to place the cue ball? Nope, unless you want to prove a point, or set someone else up to lose. You're doing the trig automatically. The pool sharks at the bar must have known this, because someone threw away Mabry's math napkins.

5. RE-TILING THE BATHROOM // CALCULUS

tiled bathroom with shower stall
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Many students don't get to calculus in high school, or even in college, but a cornerstone of that branch of math is optimization—or figuring out how to get the most precise use of a space or chunk of time.

Consider a home improvement project where you're confronted with tiling around something whose shape doesn't fit a geometric formula like a circle or rectangle, such as the asymmetric base of a toilet or freestanding sink. This is where the fundamental theorem of calculus—which can be used to calculate the precise area of an irregular object—comes in handy. When thinking about how those tiles will best fit around the curve of that sink or toilet, and how much of each tile needs to be cut off or added, you're employing the kind of reasoning done in a Riemann sum.

Riemann sums (named after a 19th-century German mathematician) are crucial to explaining integration in calculus, as tangible introductions to the more precise fundamental theorem. A graph of a Riemann sum shows how the area of a curve can be found by building rectangles along the x, or horizontal axis, first up to the curve, and then over it, and then averaging the distance between the over- and underlap to get a more precise measurement. 

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