5 Ways Radioactivity Lights Up Your Life

The word radioactivity always seems to bring up a number of glowing concerns. But maybe it's time you got over your fears and warmed up to the idea. Here are some reasons to grin about radioactivity.

1. If You Aren't Radioactive, You Just Ain't Livin'

The carbon dioxide in the air contains one part in a trillion of radiocarbon, which is radioactive and produced by cosmic rays from space. Plants, of course, take in this carbon, so then they become radioactive. If you eat plants or animals that eat plants, then you become radioactive. But why is this important? When you die, the radiocarbon will begin to decay. In 5,730 years half the radiocarbon will be gone. In another 5,730 years half of that will be gone. Because scientists can measure the age of ancient bones by measuring how much of the radiocarbon is gone, if a bone is not measurably radioactive, it means that its owner has been dead at least 50,000 years.

2. Radioactivity Helps You Get Your Drink On

The most surprising thing isn't that the Bureau of Alcohol, Firearms, and Tobacco tests alcoholic beverages for radioactivity, but that it rejects any alcohol that doesn't show radiation as "unfit." What's the reason? Any alcohol that has zero radioactivity must have come from very old carbon, and that usually means the alcohol has been manufactured from fossil fuels. After burial for 100 million years, the radio-carbon in the original organisms decays, and Congress has decreed that such alcohol may not be legally consumed. The argument that it's unfit probably has more to do with politics than with science, since there's no scientific reason why fossil fuel alcohol would be any worse than alcohol from grapes.

3. The Hills Wouldn't Be So Alive


Mountains come from the collision of large tectonic plates on the surface of the earth. Nobody knows what makes these plates move, but a reasonable guess is that the very slow flow of rocks (if they go slowly enough, they behave like fluids) is driven by the heat of radioactivity in the earth's depths. So, if it weren't for the fabulous effects of radioactivity, the plates wouldn't have moved, and those hills Julie Andrews and the Von Trapp family were so eager to sing about would never have existed.

4. You Might Be Speaking French

This is also related to the movement of the plates, discussed in the previous paragraph. About 100 million years ago, Europe and North America were one continent. And if you look on a modern map, you can still see how the continents once fit together. But the flow of rock, possibly driven by radioactivity, sent the continents apart. As a result, we have Europe and the United States. Why should we be thankful for radioactivity? Well, without it, the United States and France would probably be next-door neighbors, and Paris would seem a whole lot less exotic.

5. Ain't No Sunshine When There's No Radioactivity

The sun is driven by a process called fusion, which is actually a series of reactions that requires short-lived radioactive intermediaries to undergo a kind of radioactivity called beta decay. Simply stated, without radioactivity, the fusion on the sun could not proceed, and the sun would have cooled off billions of years ago. Needless to say, without the sun, plants and animals wouldn't be here, and you probably wouldn't have that killer tan.

Ed note: This article was pulled from Condensed Knowledge.

Essential Science
What Is Infinity?

Albert Einstein famously said: “Two things are infinite: the universe and human stupidity. And I'm not sure about the universe.”

The notion of infinity has been pondered by the greatest minds over the ages, from Aristotle to German mathematician Georg Cantor. To most people today, it is something that is never-ending or has no limit. But if you really start to think about what that means, it might blow your mind. Is infinity just an abstract concept? Or can it exist in the real world?


Infinity is firmly rooted in mathematics. But according to Justin Moore, a math researcher at Cornell University in Ithaca, New York, even within the field there are slightly different uses of the word. “It's often referred to as a sort of virtual number at the end of the real number line,” he tells Mental Floss. “Or it can mean something too big to be counted by a whole number.”

There isn't just one type of infinity, either. Counting, for example, represents a type of infinity that is unbounded—what's known as a potential infinity. In theory, you can go on counting forever without ever reaching a largest number. However, infinity can be bounded, too, like the infinity symbol, for example. You can loop around it an unlimited number of times, but you must follow its contour—or boundary.

All infinities may not be equal, either. At the end of the 19th century, Cantor controversially proved that some collections of counting numbers are bigger than the counting numbers themselves. Since the counting numbers are already infinite, it means that some infinities are larger than others. He also showed that some types of infinities may be uncountable, as opposed to collections like the counting numbers.

"At the time, it was shocking—a real surprise," Oystein Linnebo, who researches philosophies of logic and mathematics at the University of Oslo, tells Mental Floss. "But over the course of a few decades, it got absorbed into mathematics."

Without infinity, many mathematical concepts would fall apart. The famous mathematical constant pi, for example, which is essential to many formulas involving the geometry of circles, spheres, and ellipses, is intrinsically linked to infinity. As an irrational number—a number that can't simply be expressed by a fraction—it's made up of an endless string of decimals.

And if infinity didn't exist, it would mean that there is a biggest number. "That would be a complete no-no," says Linnebo. Any number can be used to find an even bigger number, so it just wouldn't work, he says.


In the real world, though, infinity has yet to be pinned down. Perhaps you've seen infinite reflections in a pair of parallel mirrors on opposite sides of a room. But that's an optical effect—the objects themselves are not infinite, of course. "It's highly controversial and dubious whether you have infinities in the real world," says Linnebo. "Infinity has never been measured."

Trying to measure infinity to prove it exists might in itself be a futile task. Measurement implies a finite quantity, so the result would be the absence of a concrete amount. "The reading would be off the scale, and that's all you would be able to tell," says Linnebo.

The hunt for infinity in the real world has often turned to the universe—the biggest real thing that we know of. Yet there is no proof as to whether it is infinite or just very large. Einstein proposed that the universe is finite but unbounded—some sort of cross between the two. He described it as a variation of a sphere that is impossible to imagine.

We tend to think of infinity as being large, but some mathematicians have tried to seek out the infinitely small. In theory, if you take a segment between two points on a line, you should be able to divide it in two over and over again indefinitely. (This is the Xeno paradox known as dichotomy.) But if you try to apply the same logic to matter, you hit a roadblock. You can break down real-world objects into smaller and smaller pieces until you reach atoms and their elementary particles, such as electrons and the components of protons and neutrons. According to current knowledge, subatomic particles can't be broken down any further.


Black holes may be the closest we've come to detecting infinity in the real world. In the center of a black hole, a point called a singularity is a one-dimensional dot that is thought to contain a huge mass. Physicists theorize that at this bizarre location, some of the singularity's properties are infinite, such as density and curvature.

At the singularity, most of the laws of physics no longer work because these infinite quantities "break" many equations. Space and time, for example, are no longer two separate entities, and seem to merge.

According to Linnebo, though, black holes are far from being an example of a tangible infinity. "My impression is that the majority of physicists would say that is where our theory breaks down," he says. "When you get infinite curvature or density, you are beyond the area where the theory applies."

New theories may therefore be needed to describe this location, which seems to transcend what is possible in the physical world.

For now, infinity remains in the realm of the abstract. The human mind seems to have created the concept, yet can we even really picture what it looks like? Perhaps to truly envision it, our minds would need to be infinite as well.

Big Questions
What Causes Turbulence?

No matter how many times you've flown, feeling a plane rattle at 35,000 feet in the air can be an unnerving experience. But turbulence, whether it's a small bump or a stomach-flipping drop, is nothing to get shaken up about. It's a normal part of flying through the ever-shifting atmosphere.

Just like a truck traversing uneven roads or a ship navigating choppy seas, planes often encounter tumultuous, or turbulent, air currents in the skies. These currents can come from several different sources. When flying over high mountains, planes sometimes experience what’s called terrain-induced turbulence. The wind flowing over the peaks and through the valleys disrupts the air thousands of feet above it, resulting in a bumpy ride for any passing aircraft.

Even when flying over flat land, pilots can run into rough patches. Air that's been heated up by the sun at ground level expands and rises to create an updraft. As this updraft travels higher it may cool and condense into a cloud. Cloud-based or convective turbulence is the easiest kind for pilots (and passengers) to spot and prepare for, but not every updraft turns into a menacing cloud. There's also something called clear air turbulence which occurs when the rising hot air is too dry to form into a cloud. Unlike convective turbulence, these problem areas are impossible to identify with the naked eye alone.

So what happens when a plane meets up with one of these drafts in midair? The effects are usually mild: perhaps enough jostling to wake you from your in-flight nap, but not quite enough to topple your drink from its tray. Of course turbulence can become more severe, but in such cases passengers tend to think they're in more danger than they actually are.

"Even in rough turbulence, the plane is never changing altitude more than 10 or 20 feet either way," co-pilot and Cockpit Confidential author Patrick Smith told Mental Floss. "There’s this idea it's plummeting hundreds of feet. Not true."

Planes are built to be tossed and throttled by volatile weather: If you ever see a wing bending like a diving board in high winds, remember it’s supposed to do that. The biggest threat during a bout of turbulence is being knocked around the cabin, which is why most turbulence injuries are sustained by flight attendants. So the next time your pilot announces rough skies ahead, find your seat, fasten your seatbelt, and make note of where the barf bags are.

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