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Rocky Raybell via Flickr // CC BY 2.0
Rocky Raybell via Flickr // CC BY 2.0

Look Up! The Eta Aquarid Meteor Shower Is Here

Rocky Raybell via Flickr // CC BY 2.0
Rocky Raybell via Flickr // CC BY 2.0

Set your alarm for the predawn hours of Saturday May 6, go outside, and catch the Eta Aquarid meteor shower—one of two annual showers caused by the collision of the Earth and the debris field of Halley’s comet. It’s not the most spectacular shower of the year, but as it peaks tomorrow morning, you can count on it to deliver a ghostly streak of light every few minutes.

The shower is named for its seeming point of origin—the constellation Aquarius—but don’t confine your view to that one spot in the sky. The streaks of light will seem to be everywhere. If your eyes have adjusted to the darkness, the skies are clear, and the area is sufficiently dark, there’s an excellent chance you’ll see something special—no telescope or binoculars required.

HALLEY’S PHANTASM

Going back millennia, every 75 to 76 years the comet Halley has appeared in the sky, dazzling and mystifying the creatures of Earth. As of 1986—its last appearance over Earth—it was visible with the naked eye despite light pollution caused by poorly designed streetlights, ill-conceived fixtures, and the over and upward illumination of buildings in areas rural and urban alike. Most of us have never seen the night sky, but rather, some poor, washed out approximation of it. You look up, think you see space, and wonder why we’re spending so much money to visit so little. A proper night sky is a kaleidoscope of greens, blues, teals, and violets. There are more stars out there than grains of sand on the Earth. The first time you see the Milky Way in all its splendor, you may wonder why we do anything other than explore the cosmos.

milky way galaxy

Lukas Schlagenhauf via Flickr // CC BY-ND 2.0

All of this bears note because for most of Halley’s history, there were no electric lights to outshine the universe. There were no planes or space stations to make illuminated objects coursing across the sky humdrum affairs filtered from thought. When something moved in the night sky back then, it was stark, obvious, and unnerving. Today we see a meteor shower and wonder how long the faint show might last. Centuries ago, people saw meteor showers and wondered if the world were about to end. The first recorded showing of Halley was possibly in 476 BCE. Aeschylus hadn’t yet written Agamemnon. The Roman Republic was in its infancy. Its recurrence has been associated with the birth of Jesus (its appearance may have coincided with the Star of Bethlehem), has been seen as a harbinger of death for royalty, and was a guiding light for Genghis Khan. Astronomy has always been as much about humanity as it is about the cosmos.

HOW TO MAKE A METEOR

The same dark skies unobscured by light pollution would have made the Aquarids—and every meteor shower to some extent—must-see viewing. Its first recorded observance was in 401 CE (the Roman Empire still stood then), and it was officially discovered in 1870. Six years later, it was calculated that the parent of the meteor shower was none other than the famed comet Halley, and people really started taking notice. As a comet travels along its orbit, it leaves a fine debris field in its wake. The Earth, happy and oblivious along its orbit, eventually crosses into the field of dust and sand-sized particles that were once part of Halley, and the result is a meteor shower: specks of dust slamming into the Earth’s atmosphere at tens of thousands of miles per hour. As they are vaporized, energy is released, producing those famed streaks of light in the night sky. (Later in Earth’s orbit, it will encounter Halley’s debris field again: the Orionids in October.)

So how can you see the phantom trail of Halley’s comet? The most exciting way is to wake a couple of hours before dawn, lay out a blanket in some dark area, and look up. Once your eyes adjust, you should be able to catch about 10 meteors per hour. If that’s too much work for you—it’s hot out there, and mosquitoes, you know?—Slooh will be broadcasting the meteor shower live, with running commentary by astronomers.

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Today's Wine Glasses Are Almost Seven Times Larger Than They Were in 1700
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Holiday party season (a.k.a. hangover season) is in full swing. While you likely have no one to blame but yourself for drinking that second (or third) pour at the office soiree, your glassware isn't doing you any favors—especially if you live in the UK. Vino vessels in England are nearly seven times larger today than they were in 1700, according to a new study spotted by Live Science. These findings were recently published in the English medical journal The BMJ.

Researchers at the University of Cambridge measured more than 400 wineglasses from the past three centuries to gauge whether glass size affects how much we drink. They dug deep into the history of parties past, perusing both the collections of the Ashmolean Museum of Art and Archaeology at the University of Oxford and the Royal Household's assemblage of glassware (a new set is commissioned for each monarch). They also scoured a vintage catalog, a modern department store, and eBay for examples.

After measuring these cups, researchers concluded that the average wineglass in 1700 held just 2.2 fluid ounces. For comparison's sake, that's the size of a double shot at a bar. Glasses today hold an average of 15.2 fluid ounces, even though a standard single serving size of wine is just 5 ounces.

BMJ infographic detailing increases in wine glass size from 1700 to 2017
BMJ Publishing group Ltd.

Advances in technology and manufacturing are partly to blame for this increase, as is the wine industry. Marketing campaigns promoted the beverage as it increasingly became more affordable and available for purchase, which in turn prompted aficionados to opt for larger pours. Perhaps not surprisingly, this bigger-is-better mindset was also compounded by American drinking habits: Extra-large wineglasses became popular in the U.S. in the 1990s, prompting overseas manufacturers to follow suit.

Wine consumption in both England and America has risen dramatically since the 1960s [PDF]. Cambridge researchers noted that their study doesn't necessarily prove that the rise of super-sized glassware has led to this increase. But their findings do fit a larger trend: previous studies have found that larger plate size can increase food consumption. This might be because they skew our sense of perception, making us think we're consuming less than we actually are. And in the case of wine, in particular, oversized glasses could also heighten our sensory enjoyment, as they might release more of the drink's aroma.

“We cannot infer that the increase in glass size and the rise in wine consumption in England are causally linked,” the study's authors wrote. “Nor can we infer that reducing glass size would cut drinking. Our observation of increasing size does, however, draw attention to wine glass size as an area to investigate further in the context of population health.”

[h/t Live Science]

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Researchers Pore Over the Physics Behind the Layered Latte
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The layered latte isn't the most widely known espresso drink on coffee-shop menus, but it is a scientific curiosity. Instead of a traditional latte, where steamed milk is poured into a shot (or several) of espresso, the layered latte is made by pouring the espresso into a glass of hot milk. The result is an Instagram-friendly drink that features a gradient of milky coffee colors from pure white on the bottom to dark brown on the top. The effect is odd enough that Princeton University researchers decided to explore the fluid dynamics that make it happen, as The New York Times reports.

In a new study in Nature Communications, Princeton engineering professor Howard Stone and his team explore just what creates the distinct horizontal layers pattern of layered latte. To find out, they injected warm, dyed water into a tank filled with warm salt water, mimicking the process of pouring low-density espresso into higher-density steamed milk.

Four different images of a latte forming layers over time
Xue et al., Nature Communications (2017)

According to the study, the layered look of the latte forms over the course of minutes, and can last for "tens of minutes, or even several hours" if the drink isn't stirred. When the espresso-like dyed water was injected into the salt brine, the downward jet of the dyed water floated up to the top of the tank, because the buoyant force of the low-density liquid encountering the higher-density brine forced it upward. The layers become more visible when the hot drink cools down.

The New York Times explains it succinctly:

When the liquids try to mix, layered patterns form as gradients in temperature cause a portion of the liquid to heat up, become lighter and rise, while another, denser portion sinks. This gives rise to convection cells that trap mixtures of similar densities within layers.

This structure can withstand gentle movement, such as a light stirring or sipping, and can stay stable for as long as a day or more. The layers don't disappear until the liquids cool down to room temperature.

But before you go trying to experiment with layering your own lattes, know that it can be trickier than the study—which refers to the process as "haphazardly pouring espresso into a glass of warm milk"—makes it sound. You may need to experiment several times with the speed and height of your pour and the ratio of espresso to milk before you get the look just right.

[h/t The New York Times]

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