Why Do We Wear Green on St. Patrick’s Day?

This woman's shirt is green and blue, probably to symbolize the complicated history of colors associated with St. Patrick.
This woman's shirt is green and blue, probably to symbolize the complicated history of colors associated with St. Patrick.
gpointstudio/iStock via Getty Images

On March 17, people (and buildings and beer) around the world get decked out in green to flaunt their Irish pride and celebrate St. Patrick’s legacy. But take a look at the earliest depictions of the famous Catholic missionary and you’ll notice something strange: He’s typically shown wearing blue, not green.

As difficult as it is to imagine, Ireland wasn’t always associated with the classic secondary color. Smithsonian.com reports that King Henry VIII sought to cement England’s centuries-old reign over the island nation by declaring himself the King of Ireland in 1541, and he even gave it a new coat of arms: a gold harp against a blue background. More than 200 years later, when King George III established an order of knights called the Order of St. Patrick, the color blue’s connection to Ireland became even more pronounced: the order’s official color was a shade of sky blue that came to be known as “St. Patrick’s blue.”

Meanwhile, Irish nationalists were looking for ways to separate themselves—politically and chromatically—from the English. According to TIME, the color green first appeared on the scene during the Great Irish Rebellion of 1641, when military commander Owen Roe O’Neill brandished a green flag with a harp to represent the Confederation of Kilkenny, which was trying to put an end to Protestant control of the region. Then, in the 1790s, the Society of United Irishmen—a revolutionary group advocating for republicanism—donned uniforms that consisted of green shirts, green and white striped pants, and felt hats with green cockades (or rosettes).

The era also gave rise to patriotic poems and ballads, many of which used the color green—and Ireland’s rich natural landscapes—as an emblem of Irish pride and resilience. In the popular ballad “The Wearing of the Green,” for example, the lyrics state that “You may pull the shamrock from your hat and cast it on the sod / But 'twill take root and flourish there, though underfoot 'tis trod.” In 1795, co-founder of the Society of United Irishmen William Drennen first referred to Ireland as “the Emerald Isle” in his poem “When Erin First Rose,” writing “Let no feeling of vengeance presume to defile / The cause of, or men of, the Emerald Isle.”

Over time, green became strongly symbolic of Ireland in general, and St. Patrick’s use of the (green) shamrock to explain the Holy Trinity in his teachings had a more lasting influence than his association with blue from the Order of St. Patrick. Green landed on Ireland’s national flag in 1848 and, as droves of Irish immigrants arrived in America throughout the 19th century, they brought with them the tradition of wearing green to celebrate his feast day.

Those celebrations didn’t always happen at pubs or involve alcohol, though—find out why here.

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Why Are Sloths So Slow?

Sloths have little problem holding still for nature photographers.
Sloths have little problem holding still for nature photographers.
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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.

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