Where Did the Myth That Radiation Glows Green Come From?

iStock
iStock

by C Stuart Hardwick

Probably from radium, which was widely used in self-luminous paint starting in 1908. When mixed with phosphorescent copper-doped zinc sulfide, radium emits a characteristic green glow:

Quora

The use of radioluminescent paint was mostly phased out by the mid-1960s. Today, in applications where it is warranted (like spacecraft instrument dials and certain types of sensors, for example), the radiation source is tritium (radioactive hydrogen) or an isotope of promethium, either of which has a vastly shorter half life than radium.

In most consumer products, though, radioluminescence has been replaced by photoluminescence, phosphors that emit light of one frequency after absorbing photons of a difference frequency. Glow-in-the-dark items that recharge to full brightness after brief exposure to sunlight or a fluorescent light only to dim again over a couple of hours are photoluminescent, and contain no radiation.

An aside on aging radium: By now, most radium paint manufactured early in the 20th century has lost most of its glow, but it’s still radioactive. The isotope of radium used has a half life of 1200 years, but the chemical phosphor that makes it glow has broken down from the constant radiation—so if you have luminescent antiques that barely glow, you might want to have them tested with a Geiger counter and take appropriate precautions. The radiation emitted is completely harmless as long as you don’t ingest or inhale the radium—in which case it becomes a serious cancer risk. So as the tell-tale glow continues to fade, how will you prevent your ancient watch dial or whatever from deteriorating and contaminating your great, great grandchildren’s home, or ending up in a landfill and in the local water supply?

Even without the phosphor, pure radium emits enough alpha particles to excite nitrogen in the air, causing it to glow. The color isn’t green, through, but a pale blue similar to that of an electric arc.

Quora

This glow (though not the color) entered the public consciousness through this early illustration of its appearance in Marie Curie’s lab, and became confused with the green glow of radium paints.

The myth is likely kept alive by the phenomenon of Cherenkov glow, which arises when a charged particle (such as an electron or proton) from submerged sources exceeds the local speed of light through the surrounding water.

So in reality, some radionuclides do glow (notably radium and actinium), but not as brightly or in the color people think. Plutonium doesn’t, no matter what Homer Simpson thinks, unless it’s Pu-238—which has such a short half life, it heats itself red hot.

Quora

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Amazon's Best Cyber Monday Deals on Tablets, Wireless Headphones, Kitchen Appliances, and More

Amazon
Amazon

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

Cyber Monday has arrived, and with it comes some amazing deals. This sale is the one to watch if you are looking to get low prices on the latest Echo Dot, Fire Tablet, video games, Instant Pots, or 4K TVs. Even if you already took advantage of sales during Black Friday or Small Business Saturday, Cyber Monday still has plenty to offer, especially on Amazon. We've compiled some the best deals out there on tech, computers, and kitchen appliances so you don't have to waste your time browsing.

Computers and tablets

Amazon

- Amazon Fire HD 10 Tablet 64GB; $120 (save $70)

- Amazon Fire HD 8 Tablet 64GB; $84 (save $35)

- HP Pavilion x360 14 Convertible 2-in-1 Laptop; $646 (save $114)

- HP Pavilion Desktop, 10th Gen Intel Core i3-10100 Processor; $469 (save $81)

- Acer Nitro 5 Gaming Laptop; $973 (save $177)

Headphones and speakers

Beats/Amazon

- Bose QuietComfort 35 II Wireless Bluetooth Headphones; $200 (save $100)

- Sony Bluetooth Noise-Canceling Wireless Headphones; $278 (save $72)

- JBL LIVE Wireless Headphones; $100 (save $30)

- JBL Charge 4 - Waterproof Portable Bluetooth Speaker; $120 (save $10)

- Bose SoundLink Color Bluetooth Speaker II; $79 (save $50)

- Powerbeats Pro Wireless Earphones; $200 (save $50)

Video Games

Sony

- Watch Dogs Legion; $30 (save $30)

- Marvel's Avengers; $27 (save $33)

- Ghost of Tsushima; $40 (save $20)

- The Last of Us Part II; $30 (save $30)

TECH, GADGETS, AND TVS

Samsung/Amazon

- Amazon Fire TV Stick; $30 (save $20)

- Echo Show 8; $65 (save $65)

- Nixplay Digital Picture Frame; $115 (save $65)

- eufy Smart Doorbell; $90 (save $30)

- Samsung 75-Inch Class Crystal 4K Smart TV; $898 (save $300)

home and Kitchen

Ninja/Amazon

- T-fal 17-Piece Cookware Set; $124 (save $56)

- Le Creuset Enameled Cast Iron Curved Round Chef's Oven; $180 (save $136)

- Ninja Foodi 10-in-1 Convection Toaster Oven; $195 (save $105)

- Roborock E4 Robot Vacuum Cleaner; $189 (save $111)

- Instant Pot Max Pressure Cooker 9 in 1; $80 (save $120)

- Shark IZ362H Cordless Anti-Allergen Lightweight Stick Vacuum; $170 (save $110)

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Why Do Cats Throw Up So Often?

Pixabay, Pexels
Pixabay, Pexels

Nearly every cat owner is used to regularly finding something their kitty coughed up hidden around their home. Vomiting in cats can happen so often that it's easy to grow desensitized to the behavior, but veterinarians say that the sight of your cat throwing up should never be ignored. Though it's usually benign, vomiting may indicate a health problem that needs to be taken care of.

To gauge whether your cat's puke is a sign of something serious, look for certain clues. According to The Spruce Pets, eating too fast is one of the most common causes of vomiting in cats, and it's usually harmless. If your cat hacks up undigested food immediately following meal times, that's likely the culprit. This behavior can be prevented by feeding your pet smaller portions, or adding an obstruction like a medium-sized ball to their bowl that they have to eat around. If the problem still persists, there may be something else causing it.

Hairballs are another potential source of your cat's retching. They may be just a gross annoyance to you, but to your cat, they can pose a serious health risk. Cats cough up the fur they can't digest, and if they don't, it could create a dangerous obstruction in their bowels. One way to help your hairball-prone cat is to brush them regularly. That way, there will be less fur for them to lick up.

These are the less concerning reasons for a cat to throw up. Vomiting can also be a symptom of health problems like feline inflammatory bowel disease, feline diabetes, hyperthyroidism, and chronic kidney disease. It's also possible that your cat ingested something harmful.

If there's no obvious explanation for your cat's vomiting, it's a good idea to reach out to your vet. While throwing up one to three times a month is considered normal, a cat that throws up multiple times in a short period may need medical attention. When analyzing your pet's behavior, look for other symptoms as well: Cats that exhibit symptoms like diarrhea or loss of appetite in addition to throwing up should always be taken to the vet.

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