What Is the Jet Stream, and How Does It Work?

Trapped between two big high-pressure systems, Hurricane Harvey has stalled over Houston, to devastating effect. As the Washington Post notes, if the jet stream were to dip far enough south, it could push Harvey out. Unfortunately, that's not in the forecast.

But what is the jet stream?

A jet stream is a swift current of air that encircles the globe right around the cruising altitude of a commercial airplane. It's easy to forget that there are vast rivers of wind whooshing just a few miles above our heads at speeds that could put most hurricanes and tornadoes to shame, but jet streams affect us every day without our realizing it. These speedy winds drive or influence just about every weather system that we have the pleasure—or misfortune—of experiencing. Planes even use it to cut down on fuel consumption and travel times.

There are usually two jet streams in each hemisphere, the polar jet and the subtropical jet. When we talk about "the jet stream," we're generally talking about the stronger polar jet stream, because most of our weather is driven by it. It's typically found at the same latitude as the U.S.-Canadian border.

We're often guilty of oversimplifying weather events by blaming everything on a clash between warm air and cold air, but temperature gradients really do have an enormous impact on where the jet stream forms and how strong it is. Jet streams form as air in the upper atmosphere moves from south to north and gets deflected to the east by the Coriolis effect. The jet stream will get stronger if the warmer temperatures are to the south and the colder the air is to the north. This is why the jet stream strengthens and dips over the United States during the winter, while it weakens and retreats north into Canada during the heat of the summer.

The jet stream drives our weather through phenomena called troughing, ridging, and jet streaks. Troughs and ridges are curves in the jet stream that are analogous to low pressure (troughs) and high pressure (ridges). In the northern hemisphere, a trough is a southward dip in the jet stream and a ridge is a northward hump in the wind current. You can expect active weather ahead of a trough and quiet weather beneath a ridge.

A jet streak is an area of much faster winds within the jet stream itself. Winds in a jet stream routinely climb above 100 mph, but the wind in a jet streak can clock speeds of more than 200 mph in a boisterous weather pattern. Troughs and jet streaks often team up to create low-pressure systems at the surface, and that's what gives birth to most of our interesting weather. Winds don't flow in a straight line as they twist around a trough or speed in and out of jet streaks. Air collides going into a trough and diverges as it leaves a trough. The same goes for jet streaks.

The process of winds exiting a trough or a jet streak, known as divergence, creates a void in the upper atmosphere. Nature hates imbalance and will do just about anything to balance something that's out of whack. When winds diverge coming out of certain parts of the jet stream, air will rush up from lower altitudes to fill the void. This upward rush of air from the surface leaves lower air pressure at the surface, creating a low-pressure system that can trigger all sorts of nasty weather.

The jet stream is also one of those weather features that could feel the effects of climate change over the coming decades and centuries. Since these wind currents rely on sharp temperature gradients in order to form, a warmer atmosphere will lessen the temperature difference between north and south and possibly create weaker jet streams. A weaker jet stream could act more erratically, creating longer stretches of quiet weather—but also more frequent weather extremes.

Watch a Gulper Eel Inflate Like a Terrifying Balloon

OET, NautilusLive.org
OET, NautilusLive.org

Since launching in 2008, the Ocean Exploration Trust's Nautilus research vessel has live-streamed a purple orb, a transparent squid, and a stubby octopus from the bottom of the ocean. The latest bizarre example of marine life captured by the vessel is a rare gulper eel that acts like a cross between a python and a pufferfish.

As Thrillist reports, this footage was shot by a Nautilus rover roaming the Pacific Ocean's Papahanaumokuakea Marine National Monument 4700 feet below the surface. In it, a limbless, slithery, black creature that looks like it swallowed a beach ball can be seen hovering above the sea floor. After about a minute, the eel deflates its throat, swims around for a bit, and unhinges its jaw to reveal a gaping mouth.

The reaction of the scientists onboard the ship is just as entertaining as the show the animal puts on. At first they're not sure what they're looking at ("It looks like a Muppet" someone says), and after being blown away by its shape-shifting skills, they conclude that it's a gulper eel. Gulper eels are named for their impressive jaw span, which allows them to swallow prey much larger than themselves and puff up to intimidate predators. Because they like to lurk at least 1500 feet beneath the ocean's surface, they're rarely documented.

You can watch the inflated eel and hear the researcher's response to it in the video below.

[h/t Thrillist]

10 Electrifying Facts About Michael Faraday

iStock
iStock

This world-changing genius was born into poverty on September 22, 1791. Fortunately for us, Michael Faraday refused to let his background stand in his way.

1. HE WAS LARGELY SELF-EDUCATED.

In Faraday's boyhood home, money was always tight. His father, James, was a sickly blacksmith who struggled to support a wife and four children in one of London's poorer outskirts. At age 13, young Faraday started helping the family make ends meet. Bookseller George Ribeau (sometimes spelled Riebau) took him on as an errand boy in 1804, with the teen's primary job being the delivery and recovery of loaned-out newspapers.

Shortly after Faraday's 14th birthday, Ribeau offered him a free apprenticeship. Over the next seven years, he mastered the trade of bookbinding. After hours, Faraday remained in Ribeau's store, hungrily reading many of the same volumes he'd bound together.

Like most lower-class boys, Faraday's formal schooling was very limited. Between those bookshelves, however, he taught himself a great deal—especially about chemistry, physics, and a mysterious force called "electricity."

2. A 300-PAGE NOTEBOOK LAUNCHED HIS SCIENTIFIC CAREER.


Wikimedia Commons // CC BY 4.0 

Sir Humphry Davy (above) left a huge mark on science. In the year 1808 alone, the man discovered no less than five elements, including calcium and boron. An excellent public speaker, Davy's lectures at the Royal Institution consistently drew huge crowds. 

Twenty-year-old Faraday attended four of these presentations in 1812, having received tickets from a customer. As Davy spoke, Faraday jotted down detailed notes, which he then compiled and bound into a little book. Faraday sent his 300-page transcript to Davy. Duly impressed, the seasoned scientist eventually hired him as a lab assistant. Later in life, Davy was asked to name the greatest discovery he'd ever made. His answer: "Michael Faraday."

Tension would nevertheless erupt between mentor and protégé. As Faraday's accomplishments began to eclipse his own, Davy accused the younger man of plagiarizing another scientist's work (this rumor was swiftly discredited) and tried to block his admission to the Royal Society.

3. IF IT WEREN'T FOR FARADAY, WE MIGHT NOT HAVE ELECTRIC POWER.

On September 3, 1821, Faraday built a device that ushered technology into the modern era. One year earlier, Danish physicist Hans Christian Ørsted had demonstrated that when an electric current flows through a wire, a magnetic field is created around it. Faraday capitalized on this revelation. Inside the Royal Society basement, he began what was arguably his most groundbreaking experiment by placing a magnet in the bottom of a mercury-filled glass container. Dangling overhead was a wire, which Faraday connected to a battery. Once an electric current was conducted through the wire, it began rotating around the magnet.

Faraday had just built the world's first electric motor. How could he possibly top himself? By building the world's first electric generator. His first experiment was comprised of a simple ring of wires and cotton through which he passed a magnet. By doing so, he found that a current was generated. To this day, most electricity is made using the same principles.

4. FARADAY INVENTED THE RUBBER BALLOON.


iStock

By today's standards, his early models would look shabby. Made via pressing two sheets of rubber together, Faraday's balloons were used to contain hydrogen during his experiments. Faraday created his first in 1824 and was quick to praise the bag's “considerable ascending power.” Toy manufacturers started distributing these the following year.

5. HE'S ALSO THE GRANDFATHER OF MODERN REFRIGERATORS.

In 1823, Faraday sealed a sample of chlorine hydrate inside a V-shaped tube. As he heated one end and cooled the other simultaneously, the scientist noticed that a peculiar yellow liquid was starting to form. Curious, he broke open the tube. Without warning, a sudden, violent explosion sent glass shards flying everywhere. Mercifully uninjured, he smelled a strong scent of chlorine in the air.

It didn't take him very long to figure out what had happened. Inside the tube, pressure was building, which liquefied the gas. Upon puncturing the glass, he'd released this pressure and, afterwards, the liquid reverted into its gaseous state. This sudden evaporation came with an interesting side-effect: it cooled down the surrounding air. Quite unintentionally, Faraday thus set the stage for the very first ice-making machines and refrigeration units.

6. HE BECAME AN ANTI-POLLUTION CRUSADER.

Britain's industrialization came at a malodorous price. As London grew more crowded during the mid-1800s, garbage and fecal matter were dumped into the River Thames with increasing regularity. Naturally, the area didn't smell like a rose. In 1855, Faraday penned an oft-reproduced open letter about the problem, imploring the authorities to take action. “If we neglect this subject,” he wrote, “we cannot expect to do so with impunity; nor ought we be surprised if, ere many years are over, a hot season give us sad proof for the folly of our carelessness.”

Just as Faraday predicted, a broiling summer forced Londoners of all stripes to hold their noses. Dubbed “the Great Stink,” the warmer months of 1858 sent the Thames' rancid odor wafting all over the city. Parliament hastily responded with a comprehensive sewage reform bill. Gradually, the putrid stench began to dissipate.

7. HE STARTED THE ROYAL SOCIETY'S CHRISTMAS LECTURE TRADITION.


Alexander Blaikley, Wikimedia Commons, Public Domain

Faraday understood the importance of making science accessible to the public. In 1825, while employed by the Royal Society, he spearheaded an annual series that's still going strong today. That holiday season, engineer John Millington delivered a set of layman-friendly lectures on “natural philosophy.” Every year thereafter (excluding 1939–1942 because of WWII), a prominent scientist has been invited to follow in his footsteps. Well-known Christmas lecturers include David Attenborough (1973), Carl Sagan (1977), and Richard Dawkins (1991). Faraday himself was the presenter on no less than 19 occasions.

8. BRILLIANT AS FARADAY WAS, HE STRUGGLED WITH MATH.

Towards the end of his life, Faraday's lack of formal education finally caught up with him. An underprivileged childhood had rendered him mathematically illiterate, a severe handicap for a professional scientist. In 1846, he hypothesized that light itself is an electromagnetic phenomenon, but because Faraday couldn't support the notion with mathematics, it wasn't taken seriously. Salvation for him came in the form of a young physicist named James Clerk Maxwell. Familial wealth had enabled Maxwell to pursue math and—in 1864—he released equations [PDF] that helped prove Faraday's hunch.

9. AS TIME WORE ON, HE STRUGGLED WITH MEMORY LOSS.

Michael Faraday
iStock

At the age of 48, Faraday's once-sharp memory started faltering. Stricken by an illness that rendered him unable to work for three years, he wrestled with vertigo, unsteadiness, and other symptoms. Following this "extended vacation" [PDF], he returned to the Royal Society, where he experimented away until his early 70s.

However, Faraday was still prone to inexplicable spurts of sudden giddiness, depression, and extreme forgetfulness. “[My] bad memory,” he wrote, “both loses recent things and sometimes suggests old ones as new.” Nobody knows what caused this affliction, though some blame it on overexposure to mercury.

10. EINSTEIN KEPT A PORTRAIT OF FARADAY IN HIS BERLIN HOME.

Fittingly, the father of modern physics regarded Faraday as a personal hero. Once, upon receiving a book about him, Einstein remarked, “This man loved mysterious Nature as a lover loves his distant beloved.”

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