Why Do We Sleep Under Blankets?

iStock
iStock

If you’re one of those people who sleeps with a sheet even on the hottest of nights, you’re not alone. Plenty of people can’t fall asleep if they aren’t covered with something, even if it’s the lightest of blankets. Why? Dan Nosowitz at Atlas Obscura reports that it’s both physiological and behavioral, and may have a component of simple conditioning.

Surprisingly, he found, sleeping with blankets is a relatively new phenomenon. Historically, blankets were expensive. Through the Middle Ages, Europeans only owned blankets if they were very wealthy. They were so precious, in fact, that bedding was passed down in people’s wills. Instead of snuggling up with a fluffy duvet, most people slept in the same bed as the rest of the household, farm animals included, to keep warm. But as fabric became cheaper and blankets more accessible, they became more commonplace household items. Now, even in tropical places, many people cover themselves with at least something during the night, with the exception of some nomadic cultures near the equator.

Part of the reason is that the body really does need extra warmth at night. Your body’s internal temperature begins to cool down before you go to bed. That’s one reason why some sleep experts recommend taking a bath or shower before bed, since your body will naturally cool off afterward, signaling to your body that it’s time to drift off. (Sticking one foot outside the covers can help, too.) Later in the night, though, that cooling off gets less pleasant and more, well, cold. During REM sleep, your body can’t regulate its own temperature. And for the most part, people tend to be in the REM stage of sleep right around dawn, when temperatures are the coldest. So we naturally learn that even if it’s pretty hot when we go to bed, we’ll wake up shivering at 4 a.m. if we don’t have a blanket.

And then there’s the neurological reason: Weighted blankets have been found to decrease anxiety and stress, because gentle pressure can stimulate serotonin production. Serotonin has been found to help modulate sleep regulation, which is part of the reason that depression and insomnia are linked—when you’re depressed, your serotonin levels are low.

There are more simple psychological reasons to cover up, too. When you’re a baby, your parents put blankets on you when you sleep, so you’re conditioned throughout your early years to associate blankies with bedtime. Above all, maybe we just all want to be swaddled forever. Doesn't that sound nice?

[h/t Atlas Obscura]

Why Are Sloths So Slow?

Sloths have little problem holding still for nature photographers.
Sloths have little problem holding still for nature photographers.
Geoview/iStock via Getty Images

When it comes to physical activity, few animals have as maligned a reputation as the sloth. The six sloth species, which call Brazil and Panama home, move with no urgency, having seemingly adapted to an existence that allows for a life lived in slow motion. But what makes sloths so sedate? And what horrible, poop-related price must they pay in order to maintain life in the slow lane?

According to HowStuffWorks, the sloth’s limited movements are primarily the result of their diet. Residing mainly in the canopy vines of Central and South American forests, sloths dine out on leaves, fruits, and buds. With virtually no fat or protein, sloths conserve energy by taking a leisurely approach to life. On average, a sloth will climb or travel roughly 125 feet per day. On land, it takes them roughly one minute to move just one foot.

A sloth’s digestive system matches their locomotion. After munching leaves using their lips—they have no incisors—it can take up to a month for their meals to be fully digested. And a sloth's metabolic rate is 40 to 45 percent slower than most mammals' to help compensate for their low caloric intake. With so little fuel to burn, a sloth makes the most of it.

Deliberate movement shouldn’t be confused for weakness, however. Sloths can hang from branches for hours, showing off some impressive stamina. And because they spend most of their time high up in trees, they have no need for rapid movement to evade predators.

There is, however, one major downside to the sloth's leisurely lifestyle. Owing to their meager diet, they typically only have to poop once per week. Like going in a public bathroom, this can be a stressful event, as it means going to the ground and risking detection by predators—which puts their lives on the line. Worse, that slow bowel motility means they’re trying to push out nearly one-third of their body weight in feces at a time. It's something to consider the next time you feel envious of their chill lifestyle.

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Are Any of the Scientific Instruments Left on the Moon By the Apollo Astronauts Still Functional?

Apollo 11 astronaut Neil Armstrong left the first footprint on the Moon on July 20, 1969.
Apollo 11 astronaut Neil Armstrong left the first footprint on the Moon on July 20, 1969.
Heritage Space/Heritage Images/Getty Images

C Stuart Hardwick:

The retroreflectors left as part of the Apollo Lunar Ranging Experiment are still fully functional, though their reflective efficiency has diminished over the years.

This deterioration is actually now delivering valuable data. The deterioration has multiple causes including micrometeorite impacts and dust deposition on the reflector surface, and chemical degradation of the mirror surface on the underside—among other things.

As technology has advanced, ground station sensitivity has been repeatedly upgraded faster than the reflectors have deteriorated. As a result, measurements have gotten better, not worse, and measurements of the degradation itself have, among other things, lent support to the idea that static electric charge gives the moon an ephemeral periodic near-surface pseudo-atmosphere of electrically levitating dust.

No other Apollo experiments on the moon remain functional. All the missions except the first included experiment packages powered by radiothermoelectric generators (RTGs), which operated until they were ordered to shut down on September 30, 1977. This was done to save money, but also because by then the RTGs could no longer power the transmitters or any instruments, and the control room used to maintain contact was needed for other purposes.

Because of fears that some problem might force Apollo 11 to abort back to orbit soon after landing, Apollo 11 deployed a simplified experiment package including a solar-powered seismometer which failed after 21 days.

This post originally appeared on Quora. Click here to view.

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