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What Exactly Is a Pixel?

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When talking about televisions, all this 720p, 1080p, and 4K can seem a bit confusing, especially if you just want to watch a movie or TV show in the comfort of your home and have it look as good as possible. But having the image look as good as possible all boils down to the small building block called the pixel, a word that most people have heard about, but not one that many fully understand. 

“Pixel” is a term derived from the words “picture” and “element,” and is the smallest representative unit of a digital image. Pixels are normally situated in a two-dimensional grid (like your television screen), and the number of pixels in that grid determines its overall resolution.

These primarily square or rectangular-shaped units were first designated in 1965 by American engineer Frederic C. Billingsley who, while working at CalTech’s Jet Propulsion Laboratory, described small pixels in images sent back to earth from NASA space probes exploring the moon and Mars. Pixels as a photographic concept have had a long and complicated history but can trace their origins back to German inventor Paul Nipkov’s concept of the “Bildpunkt,” or the dissected image of a “picture point.” Nipkov used this concept when he patented the world’s first mechanized television system way back in 1884. 

Current high-definition televisions are situated in two common fixed arrangements for pixel resolution, the minimum of 720p or maximum of 1080p (in this case the “p” does not stand for “pixel,” but we’ll get to that in a moment). The 720 refers to 1280 x 720, or the horizontal and vertical numbers of pixels on a given screen. Likewise, the 1080 refers to a standard horizontal count of 1920 x 1080 vertical count of pixels in the grid. Multiplied together, these numbers of pixels indicate the maximum amount of image detail found on your screen, which is important for the sharpness and level of vivid detail able to be seen on modern HD-TVs. Contrasted to the over 2 million pixels in a 1080p screen, old standard definition screens had around 300,000 pixels, which displayed a less detailed, much blurrier picture.

Though it may be slightly confusing, the “p” in 720p or 1080p stands for “progressive-scan,” and refers to the way the complete high-definition picture is sent to the pixels that make up your screen all at a single time. The opposite of progressive-scan is the outdated “interface-scan,” represented as “i,” which projects its picture into two separate fields on a TV screen at different times, thus causing the slight flickering effect seen on old television sets.

The resolution on consumer electronics like TVs will only get higher, and with the advent of 4K resolution—screens with at least 4,000 pixels in a horizontal grid that packs in four times the pixels of a 1080p screen—digital images will continue to improve and become more realistic in color and crispness. But just remember, it all comes down to one small but essential component—the pixel. 

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Why Does the Queen Have Two Birthdays?
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On April 21, Her Majesty Queen Elizabeth II will turn 92 years old. To mark the occasion, there are usually a series of gun salutes around London: a 41 gun salute in Hyde Park, a 21 gun salute in Windsor Great Park, and a 62 gun salute at the Tower of London. For the most part, the monarch celebrates her big day privately. But on June 9, 2018, Her Majesty will parade through London as part of an opulent birthday celebration known as Trooping the Colour.

Queen Elizabeth, like many British monarchs before her, has two birthdays: the actual anniversary of the day she was born, and a separate day that is labeled her "official" birthday (usually the second Saturday in June). Why? Because April 21 is usually too cold for a proper parade.

The tradition started in 1748, with King George II, who had the misfortune of being born in chilly November. Rather than have his subjects risk catching colds, he combined his birthday celebration with the Trooping the Colour.

The parade itself had been part of British culture for almost a century by that time. At first it was strictly a military event, at which regiments displayed their flags—or "colours"—so that soldiers could familiarize themselves. But George was known as a formidable general after having led troops at the Battle of Dettingen in 1743, so the military celebration seemed a fitting occasion onto which to graft his warm-weather birthday. Edward VII, who also had a November birthday, was the first to standardize the June Trooping the Colour and launched a tradition of a monarchical review of the troops that drew crowds of onlookers.

Even now, the date of the "official" birthday varies year to year. For the first seven years of her reign, Elizabeth II held her official birthday on a Thursday but has since switched over to Saturdays. And while the date is tied to the Trooping the Colour in the UK, Commonwealth nations around the world have their own criteria, which generally involve recognizing it as a public holiday.

Australia started recognizing an official birthday back in 1788, and all the provinces (save one) observe the Queen's Birthday on the second Monday in June, with Western Australia holding its celebrations on the last Monday of September or the first Monday of October.

In Canada, the official birthday has been set to align with the actual birth date of Queen Victoria—May 24, 1819—since 1845, and as such they celebrate so-called Victoria Day on May 24 or the Monday before.

In New Zealand, it's the first Monday in June, and in the Falkland Islands the actual day of the Queen's birth is celebrated publicly.

All in all, just another reason it's great to be Queen.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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What Is the Meaning Behind "420"?
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Whether or not you’re a marijuana enthusiast, you’re probably aware that today is an unofficial holiday for those who are. April 20—4/20—is a day when pot smokers around the world come together to, well, smoke pot. Others use the day to push for legalization, holding marches and rallies.

But why the code 420? There are a lot of theories as to why that particular number was chosen, but most of them are wrong. You may have heard that 420 is police code for possession, or maybe it’s the penal code for marijuana use. Both are false. There is a California Senate Bill 420 that refers to the use of medical marijuana, but the bill was named for the code, not the other way around.

As far as anyone can tell, the phrase started with a bunch of high school students. Back in 1971, a group of kids at San Rafael High School in San Rafael, California, got in the habit of meeting at 4:20 to smoke after school. When they’d see each other in the hallways during the day, their shorthand was “420 Louis,” meaning, “Let’s meet at the Louis Pasteur statue at 4:20 to smoke.”

Somehow, the phrase caught on—and when the Grateful Dead eventually picked it up, "420" spread through the greater community like wildfire. What began as a silly code passed between classes is now a worldwide event for smokers and legalization activists everywhere—not a bad accomplishment for a bunch of high school stoners.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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