What's the Difference Between Mold and Mildew?

iStock.com/AndreasReh
iStock.com/AndreasReh

We’re all familiar with colorful spots of something growing in our showers and in other dark, damp areas in our homes, but you may not know what to call it. Is it mold, or is it mildew? What is the difference between the two, anyway?

Both terms refer to fungus, but as it happens, it’s a squares-versus-rectangles situation. Mildew is a type of mold. The term typically describes fungi that grows flat, on surfaces like the walls of your shower or window sills. There are also several types of mildew that are specific to plants—powdery mildew and downy mildew are parasites that grow on certain trees, flowers, and crops, for example. While mold might be a colorful green or black, mildew is typically white.

The word mildew originally came from honeydew, a term for sticky secretions aphids and other insects leave on plants, which people used to think came from the sky, like dew. Eventually, the word came to refer to the mold caused by the fungi that fed on these secretions.

Leaves covered in white powder
Powdery mildew on maple leaves
iStock.com/kazakovmaksim

Most of the household growths we refer to as mold belong to just a few families of fungi species. According to the CDC, the most common indoor molds are Cladosporium, Penicillium, Aspergillus, and Alternaria. Household molds can be a variety of colors, from orange-brown to green to gray to black. (Note that not all mold that is black in color is the more toxic species we call “black mold,” or Stachybotrys.) In contrast to the powdery texture of mildew, molds are typically fuzzy or slimy.

In nature, mold can play an important role in the ecosystem, breaking down dead plants and leaves. In your house, those decomposition abilities aren’t quite so welcome. Mold spores fly through the air, and when they land in moist places, they start to grow—whether that’s on food, your ceiling, paper products, wood, carpet, leather, or elsewhere around your house—and in the process, destroy whatever they're growing on. Unlike mildew, most molds grow down into the surface of its habitat, making them more difficult to remove. In porous materials, mold grows into all the empty crevices, which is why it is often impossible to remove all the mold from ceiling tiles (or soft foods like bread).

Mold growing under a windowsill and near the carpet of a home
Mold growing in a Nashville home following a flood
Martin Grube, FEMA // Public Domain

Getting rid of the unsightly growth in your damp bathroom is more than just a matter of aesthetics. Indoor mold can cause allergic reactions, such as a stuffy nose or itchy eyes, and can lead to infections for people with compromised immune systems. Some people are more sensitive to mold than others, and may experience more symptoms when exposed to it. Generally speaking, though, mold spores are everywhere, so you’re never going to live a totally mold-free life. Spores will come into your home through windows, doorways, ventilation and climate control systems, and via your clothing, shoes, and pets.

But there’s only one way to effectively inhibit mold growth at home: Get rid of the moisture. That means fixing leaks, getting better ventilation, and possibly running a dehumidifier, according to the CDC’s recommendations on mold.

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Who Has Jurisdiction for Crimes Committed in Space?

iStock/nedelcupaul
iStock/nedelcupaul

It's 2050. Humans have mastered commercial space travel. Hundreds of people pay thousands of dollars to be sent into orbit in a spaceship. Maybe some decide to help colonize Mars.

Then, trouble. A jilted spouse. A smuggled firearm. Perhaps a struggle followed by suffocation. A space traveler is found dead on board a ship or on the Red Planet. Who has jurisdiction over such crimes? Is there such a thing as a cosmic Hercule Poirot? Could someone fall through the cracks and get away with space murder?

To date, no one has been victim of a space crime. But because no one nation can lay claim to ownership of space, the idea of a criminal offense committed outside of our atmosphere is something people have already given some thought to.

According to NASA engineer and instructor Robert Frost, the language of law for galactic felonies would be the Outer Space Treaty of 1967. In Article VIII of the treaty, nations engaging in space exploration agree that they will bear responsibility for the actions of personnel aboard their craft. In other words, if a privatized shuttle from China sees a fight break out among crew members, leaving one injured, China would be the entity responsible for handling legal repercussions.

That varies slightly with the International Space Station, or ISS, which is home to a number of personnel from different nations. In the case of the ISS, an intergovernmental agreement signed in 1998 mandates that the home country of the offender will handle any investigation or prosecution. If the victim is a national of another country, that country will have the right to inquire as to the criminal status of the offender and seek to have jurisdiction over the matter if they feel justice isn't being meted out.

In most cases, space crime sprees would be treated the same as if an offender was traveling in a foreign country or in international waters. If you're a U.S. citizen and decide to bludgeon someone at sea or on the Moon, the various international agreements and national laws would determine how you get prosecuted. (Assuming, of course, you returned to Earth to answer the charges.)

Space crimes pose another intriguing wrinkle. In terra firma investigations, authorities can secure crime scenes, question witnesses, and preserve evidence. Aboard a spaceship or on a distant planet, these procedures would be difficult to perform, and almost impossible to do in a timely fashion. Even if a criminal investigator is on Mars, low gravity will affect blood spatter and bodies may even decay at a different rate than they do on Earth. While an American may be found liable for murder, proving it was malicious and not the result of the dangerous environment would give any prosecutor a headache. A defense attorney, on the other hand, would have a field day questioning defective spacesuits or toxic exposure to strange space chemicals.

Then again, prosecutors may not have to concern themselves with evidence. Thanks to airlocks and restrictive suits, the movement of space travelers is highly monitored. It would be hard to make any plausible deniability about one's whereabouts.

The closest thing to space crime that law enforcement has yet encountered may be crimes committed in Antarctica, the frigid and isolated continent that's unaffiliated with any country but operates under the Antarctic Treaty signed by 54 nations. The agreement declares that the suspect is likely under their home country's jurisdiction. In some cases, the country owning the research station where the alleged crime took place steps in. In 2018, a Russian researcher at Bellingshausen Station on King George Island went after his victim with a knife in the station's dining room. He was charged in Russia, though reports indicate the case has since been dropped. And in 2000, an Australian astrophysicist suspected of being fatally poisoned had an autopsy performed in New Zealand. The exam showed he had ingested methanol, but it remains unknown whether he did so accidentally or whether someone gave it to him. New Zealand police were unable to determine the source.

A person committing murder in space would certainly be held responsible. But whether they'd ever be found guilty beyond a reasonable doubt remains very much up in—and beyond—the air.

Why Do Dogs Eat Grass?

iStock/K_Thalhofer
iStock/K_Thalhofer

If something is edible (or even if it's not), many dogs will gladly make a meal of it. But if you see your pet grazing on your front lawn like cattle, it may be driven by something more than its undiscerning appetite. Eating grass frantically can be a sign that a dog is sick.

It's not unusual to see a dog vomit after consuming grass, prompting some pet owners to wonder if their dog ate the grass to soothe its own upset stomach or if the grass is what caused its symptoms in the first place. According Dr. Jerry Klein, chief veterinary officer for the American Kennel Club, this behavior is sometimes a response to symptoms that were already present. "When dogs go outside and gobble grass really quickly, there's usually a reason, an instinctual behavior to try to induce some kind of gastrointestinal reaction," he tells Mental Floss. "When they realize they're nauseous or something else, the only thing they know how to do is to force themselves to vomit. Some dogs that eat grass chomp it down without really chewing it, and often times may vomit something up and that's how they treat themselves."

Despite it being a common issue for pet owners, little research has been done into why dogs eat grass. It's likely that stomach problems only explain this behavior part of the time. In other situations, a dog may eat grass for the same reason it eats your shoes or the groceries you left on the kitchen counter: Because it's hungry, anxious, or bored.

So how can you tell when your dog is munching grass for pleasure and when it's trying to induce itself to vomit? Pay attention to the way it eats. Dogs are omnivorous, meaning they eat both plants and animals, so just eating grass alone normally won't be enough to make it sick. But if a dog is gorging on grass faster than it can chew it, that may be an indication that something is wrong. Whole blades of grass can irritate a dog's throat and stomach lining, potentially causing them to throw up if they swallow a lot of them in a short amount of time.

No matter the reason for your dog's grass-eating habits, Klein says that they aren't a major issue. The behavior shouldn't be encouraged, as grass in public places can potentially carry harmful chemicals like pesticides, so stop your dog if you see it grazing. But if it shows no signs of illness or discomfort afterward, there's no need to rush it to the vet. "If I see a dog eating grass, I'm not going to panic. I would try to stop it and then monitor it to see how it acts in the next 15 to 20 minutes. Look at how the dog's acting, its body shape and movement, and the feeling you get from the dog."

One condition related to vomiting that would warrant a trip to the vet is something called bloat. This happens when a dog's stomach fills with air, causing it to retch without actually throwing anything up. This is a medical emergency and can be deadly if left untreated.

A dog who vomits after eating grass and looks happy afterward, on the other hand, is probably not a cause for concern—though you may argue otherwise when you're steam-cleaning your carpet.

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