The Event Horizon Telescope: How It Works

By Erika K. Carlson | April 10, 2019 8:20 am
ALMA

The Atacama Large Millimeter/submillimeter Array (ALMA). (Credit: ESO/C. Malin)

A black hole isn’t an easy thing to photograph. The famously inscrutable objects are so dense that even light can’t escape their vicinity. By definition, they are invisible. So when the Event Horizon Telescope team released the first image of a black hole, what they really released is an image of the black hole’s event horizon — the minimum distance from the black hole’s center where gravity is still weak enough for light to escape.

And how they imaged the supermassive black hole in galaxy M87 it is nearly as impressive as the image itself. EHT scientists convinced researchers around the world to point their radio telescopes at a select group of black holes, then combined the observations to create one giant array the size of our planet.

“With this technique, we were able to use essentially the diameter of the Earth as the resolving power,” says John Carlstrom, who heads the EHT partnering South Pole Telescope. That let them glimpse finer details than even the Hubble Space Telescope can.


Read more: Astronomers Get Their Very First Picture of a Black Hole


Imaging a Monster

In 2017, the EHT turned its gaze to supermassive black holes at the centers of two galaxies: our own Milky Way and an elliptical galaxy about 50 million light-years away called M87. Each of these astronomical monsters has a disk of material — gas, dust, plasma, what have you — swirling around the black hole. That material heats up and glows until it eventually falls in. By capturing an image of the glowing disk around M87’s black hole, and the dark inner edge caused by the black hole’s event horizon, scientists not only made history, but also expanded our knowledge of how black holes work.

M87 Jet

Taken by the Hubble Space Telescope, this image shows a jet of matter blasting from galaxy M87. (Credit: NASA and The Hubble Heritage Team (STScI/AURA))

So why haven’t astronomers snapped such a pic before? Because it’s an incredibly difficult feat. One of the biggest challenges is how tiny a target they actually are. Supermassive black holes have a lot of mass, sure, but they’re also super compact. The one in the center of our galaxy, called Sagittarius A* (Sgr A*), has an event horizon smaller across than the distance between the sun and Earth. And it’s roughly 26,000 light-years away, so it takes up a minuscule amount of sky — just a few billionths the width of the full moon. The black hole at the center of M87 is a whopping 1,000 times bigger than our own but it also sits roughly 2,000 times farther away. So it’s more or less the same size in Earth’s sky as Sgr A*. To photograph either black hole, you need a really powerful telescope.

Generally, the resolution of a telescope — how small of a target it can see — comes down to its size. The larger the telescope, the more resolving power it has, and the smaller the details it can make out. But even the largest radio dishes in the world, like the Arecibo Observatory in Puerto Rico and the Five-hundred-meter Aperture Spherical Telescope in China (each more than 1,000 feet across), aren’t big enough to image these black holes.


Read more: The Event Horizon Telescope’s Quixotic Quest to Image a Black Hole


Black Hole Photography 101

Radio astronomers can get around this problem by linking together lots of smaller radio dishes into a single array, where they effectively act as one giant telescope. It’s a technique called astronomical interferometry. Each dish in the array collects light from a target object, like the glowing disk around a black hole, and converts the radio waves it receives into an electronic signal. Then a computer called a correlator combines all the electronic signals from the various dishes into what’s called an interference pattern. Finally, astronomers tapped a special kind of math (Fourier transforms for the curious) to decode that pattern, showing what the target would look like in the sky if our eyes could see in radio wavelengths.

Very Large Array

The Very Large Array in New Mexico, which is part of the larger Event Horizon Telescope. (Credit: Alex Savello/NRAO)

With an array of radio telescopes, it’s the distance between individual dishes, rather than the diameter of a single dish, that determines the array’s resolving power. The farther apart two dishes are, the better the resolving power of that array. That’s why radio observatories like the Very Large Array in New Mexico and the Atacama Large Millimeter Array in Chile can have dishes miles apart. But even these arrays aren’t big enough to resolve the tiny radio speck in the sky that is the supermassive black hole in the Milky Way, or the one in M87.

So, to really crank up the resolution, the EHT used a form of this technique called very-long baseline interferometry. Instead of relying on a single location, astronomers combined data from telescopes in entirely different areas — different continents even — using precise atomic clocks and GPS systems to carefully time the observations and keep everything in sync.

“You can put your antennas anywhere on the Earth that you like. You can put one in California, and put one in West Virginia,” says Jim Braatz, an astronomer at the National Radio Astronomy Observatory who is not part of the EHT collaboration. “With those two antennas, you can kind of simulate or mimic a telescope with the diameter of the whole country.”

The EHT has taken that to a global scale to make a telescope as big as our entire planet. Radio telescopes in Arizona, Hawaii, Mexico, Chile, Spain and even Antarctica all observed their black hole targets in tandem. With dishes spread as far as possible, the EHT aims for nothing less than the maximum resolution a radio array can get without leaving Earth.

“In general, the more pairs of antennas that you have,” Braatz says, “the better the image you’ll get at the end of the day.” That’s why this first black hole image is so impressive — and it’s just the first of many results we’ll soon see from the EHT.

The research is published today in The Astrophysical Journal Letters.

CATEGORIZED UNDER: Space & Physics, Top Posts

Inside The Event Horizon Telescope’s Quixotic Quest to Image a Black Hole

By Steve Nadis | April 10, 2019 8:15 am
The Atacama Large Millimeter/submillimeter Array is part of the globe-spanning Event Horizon Telescope effort to directly image a black hole. (Credit: ESO/C. Malin)

The Atacama Large Millimeter/submillimeter Array is part of the globe-spanning Event Horizon Telescope effort to directly image a black hole. (Credit: ESO/C. Malin)

Trying to take a picture of a black hole — an object that is, by definition, invisible—sounds like an exercise in futility. But for decades, theoreticians suspected it may just be possible to get a detailed view of a black hole’s perimeter, right up to the edge of the event horizon, the fabled point of no return. And a core group of astronomers spent years trying to turn that prediction into reality. Now, they finally have.

Astronomers announced Wednesday that they’d captured a clear view of the supermassive black hole in galaxy M87. It was a truly international unveiling, with press conferences held around the world — a fitting stage to describe the results of an astronomical instrument, the Event Horizon Telescope (EHT), that also spans the globe.

Their results were published in a series of six papers released Wednesday in The Astrophysical Journal Letters.

Here is the first direct image of a supermassive black hole. Captured by the Event Horizon Telescope, a network of eight radio telescopes spread across the world, the image shows the bright, spinning disk of material around the galaxy M87's supermassive black hole. Due the the intense gravity present near black holes, the appearance of the disk is warped. (Credit: EHT Collaboration)

Here is the first direct image of a supermassive black hole. Captured by the Event Horizon Telescope, a network of eight radio telescopes spread across the world, the image shows the bright, spinning disk of material around the galaxy M87’s supermassive black hole. Due the the intense gravity present near black holes, the appearance of the disk is warped. (Credit: EHT Collaboration)

Party like it’s 1999

The idea of black holes dates back to at least 1783, when British scientist John Michell suggested that our universe harbored “dark stars” whose density was so great and gravity so strong that “all light emitted from such a body would be made to return towards it.” But the notion of possibly seeing one is much more recent, and relies on the counterintuitive idea that an invisible object still casts a visible shadow — in this case a darkened region, or silhouette, extending inward from the event horizon, bounded by a ring of hot, luminous gases. Read More

CATEGORIZED UNDER: Space & Physics, Top Posts

The Human Brain Has been Getting Smaller Since the Stone Age

By Bridget Alex | April 8, 2019 5:15 pm
(Credit: Discover magazine; Tory Kallman/Shutterstock and Hein Nouwens/Shutterstock, after Die Frau als Hausarztin (1911))

(Credit: Discover magazine; Tory Kallman/Shutterstock and Hein Nouwens/Shutterstock, after Die Frau als Hausarztin (1911))

I don’t mean to alarm you, but the average human brain size is shrinking. And we can’t blame reality T.V. or twitter. No, this decline began tens of thousands of years ago.

It’s something of a well-known secret among anthropologists: Based on measurements of skulls, the average brain volume of Homo sapiens has reportedly decreased by roughly 10 percent in the past 40,000 years. This reduction is a reversal of the trend of cranial expansion, which had been occurring in human evolution for millions of years prior (see chapter 17).

Let’s review the boney evidence backing this observation, then explore some potential explanations.

And just to ease your anxiety: Although you may have a smaller cranium than our Stone Age predecessors, human brains today are still about three times the size that’s normal for a primate with our body weight. Read More

CATEGORIZED UNDER: Living World, Top Posts

Analysis of 4 Million Pitches Reveals Umps Really Do Suck at Calling Strikes

By Mark T. Williams, Boston University | April 8, 2019 4:40 pm
baseball umpire

(Credit: Richard Paul Kane/Shutterstock)

Baseball is back, and fans can anticipate another season of amazing catches, overpowering pitching, tape-measure home runs – and, yes, controversial calls that lead to blow-ups between umpires and players.

Home plate umpires are at the heart of baseball; every single pitch can require a judgment call. Yet ask any fan or player, and they’ll tell you that many of these calls are incorrect – errors that can affect strategy, statistics and even game outcomes.

Just how many mistakes are made? Read More

CATEGORIZED UNDER: Technology, Top Posts
MORE ABOUT: computers

Craft Beer’s Quest For The Funky Flavors of Wild Yeast

By Anna Groves | April 5, 2019 5:15 pm
A brewer watches beer bottles track down a factory line. (Credit: Jacob Lund/Shutterstock)

A brewer watches beer bottles track down a factory line. (Credit: Jacob Lund/Shutterstock)

Whether your preferred pint is crisp or hoppy, fruity or caramelly, you owe a lot to the single-celled fungus doing the important work of putting the booze in your brews. Hops may get most of the love on the craft beer scene, but yeast is an overlooked heavy-hitter when it comes to giving beer flavor.

“Cool people are obsessed with yeast,” says Simon McConico, co-owner of Milwaukee’s Vennture Brew. “It’s because hops are sexy; yeast is a bit more nuanced.”

He adds, “Yeast is starting to get more sexy among nerds.”

Scientists are buying in, too. Ever since a microbiology expedition to the mountains of Patagonia uncovered a new wild yeast species in 2011, scientists have been hard at work on ingredients that may soon bring totally new flavors to a beer near you.

yeast

Saccharomyces cerevisiae, also known as brewer’s yeast, has long been vital for making ale, wine and bread. (Credit: Illustration by Kateryna Kon/Shutterstock)

Yeast 101

The art of brewing can be broken down into a just a few key steps. First, grains are soaked until they start to germinate; then they’re roasted. Roasting is the first beer flavor checkpoint: lighter roasts might get turned into pale ales or pilsners; darker roasts into porters and stouts. Then this malt gets mashed and boiled, which converts the starches in the grain into sugars. Hops are added to make the wort — hot, sweet food for yeast. That’s when it’s ready-to-ferment.

Yeast arrives and eats up the sugars, turning them into alcohol, carbon dioxide and flavor compounds. However, just two yeast species are currently used to make beer: Brewer’s yeast (Saccharomyces cerevisiae) and lager yeast (Saccharomyces pastorianus.) The former comes in hundreds of strains, which can impart all sorts of different flavors on a beer.


Brewing Better Beer, With Wild Yeast and Genetics


If you’ve tasted banana, butterscotch or clove in a beer — that’s a byproduct from the yeast. You might find flavors that are spicy, sweet, tangy, medicinal or even musky. And just last year, the yeast flavor palate was really rounded out after scientists engineered yeast to produce the bitter yet aromatic flavors of hops.

Sierra Nevada brewing

Sierra Nevada Brewing Company’s North Carolina location. (Credit: digidreamgrafix/Shutterstock)

A lot of major breweries have a main house yeast strain they use for most of their brews. Stone, for example, uses a strain that originated at a now-defunct Canadian microbrewery and is cultured at beer-yeast-powerhouse White Labs. Lagunitas and Sierra Nevada are rumored to have house strains, too. These brewers get clever with different grains, hops, recipes, and techniques to come up with new pints. Some beer fans speculate that reliance on a house strain gives these mega-craft brews a signature flavor, for better or for worse.

A Literal Quest for Lager Yeast

Hundreds of years ago, brewers figured out that if they turned down the temps during the brewing process, they’d end up with the crisper, cleaner beer that still dominates the beer market today: lagers. Now we know that those lower temps are critical because they keep rogue yeasts and bacteria out of the brew. Only lager yeast can tolerate the cold.

Louis Pasteur, the godfather of yeast, discovered fermentation is caused by living things. (Credit: Everett Historical/Shutterstock)

Louis Pasteur, the godfather of yeast. (Credit: Everett Historical/Shutterstock)

For a long time, the lager yeast itself was a bit of a mystery. For the first century or so that we even knew it existed, we thought it was its own species: Saccharomyces pastorianus, named after Louis Pasteur, who discovered that fermentation was caused by living organisms.

But in the 1980s, scientists discovered that lager yeast wasn’t a species of its own at all, but a hybrid: a cross between the common brewer’s yeast used in all the other ales, and something else. Something else, not yet known to science, which passed on the critical characteristic of cold tolerance to the lager yeast.

This wild lager yeast ancestor remained a mystery for decades, until a microbiologist on a sampling expedition in Patagonia found a new Saccharomyces species growing on a beech tree in a remote mountainside in Patagonia. In the cold.

It was the missing yeast. They named it S. eubayanus. And its discovery in 2011 has opened up a new realm of possibilities for scientists — and brewers.


Everything Worth Knowing About … Yeast


New Yeast On The Block

Chris Hittinger is a University of Wisconsin microbiologist who’s researched Saccharomyces for years. He says this wild yeast discovery was a big step forward for the field. Since then, his lab has been setting the groundwork that could set us up for some pretty sweet brews in the future.

First, his research team figured out exactly how the wild yeast crossed with brewer’s yeast to make lager yeast. Through experiments crossing the two yeasts, they learned that the key to cold tolerance in lager yeast was in the mitochondria — organelles that make energy for the cell and hold a little bit of DNA — coming from the wild yeast.

This find allowed them to re-create lager yeast in the lab — which means new lager yeasts could now be developed from new crosses. “There’s just a lot more genetic diversity on the table,” says Hittinger.

Next they studied whether they could coax the wild yeast to evolve into something that could be used to brew. On its own, the wild yeast wouldn’t cut it as a beer fermenter. Maltotriose, the second-most abundant sugar in brewing worts, is too big of a molecule for nature’s version to eat.

In search of a solution, the scientists set out on an experiment that created 1,000 generations of wild yeast grown. It failed. Then they switched gears, instead trying to select for a wild yeast that was extra good at eating a different sugar: maltose, the most common sugar in brewing worts. Within two days, their yeast could grow four times more rapidly when given maltose. And, thanks to some genetic serendipity, it also gained the ability to digest maltotriose. They’d succeeded on accident.

Hittinger’s team had created a version of the wild yeast that could be used in lager production. But it’s a whole different species, meaning it could make a lager with a completely different flavor profile than we’re used to.

What kinds of flavors?

“One thing you get from the wild is what the industry calls phenolic off-flavors. And we’re starting to get to the genetic basis of what those flavors are,” Hittinger says. “We know that for some beer styles, those basically drive consumer preferences: like Weiss beers, Chimay-style, Trappist [beers], those are key flavor components and those come through in the wild lagers.”

Heineken's visitor center

Glistening brew tanks are the centerpiece of Heineken’s visitor center in Amsterdam. (Credit: Anton Ivanov/Shutterstock)

Something About Yeast

Heineken was first to step up to the plate after news broke of the wild yeast discovery. They released their first “wild lager” back in 2017, named H41 for the latitude where the yeast was discovered. It’s not clear how Heineken’s brewers got around the issue of the wild yeast not digesting all the sugars — their brew came out more than two years before Hittinger’s lab developed the new maltotriose-digesting strain.

But harnessing the flavors of wild yeasts isn’t exactly new to brewers. Before they opened, a proto-Vennture brew used yeast collected from peach trees down the road from the brewery. McConico explains that yeast is all around us in the environment. “You can basically culture yeast out of anything,” he says. “Whether or not it will ferment is a different story.”

Farther back in time, wild yeasts gave traditional “Farmhouse Ales” their unique-to-the-barn-it-was-brewed-in flavors. Modern beers, especially sours, are once again embracing some of these natural flavors, looking beyond strains of the traditional brewer’s and lager yeasts to species like Brettanomyces to ferment their wort.

And last year, a group led by biologist Richard Preiss from the University of Guelph sequenced strains of traditional Norwegian Kveik (pronounced something like, K-why-k) yeast, learning that they are a genetically distinct subset of common brewer’s yeaststrains that have been passed down through generations by local Norwegian brewers and have some interesting qualities. Global brewers are interested in Kveik because it can brew faster and at a hotter temperature than other strains of brewer’s yeast.

“Since craft beer has grown so much, people are looking for ways to be new and interesting,” says McConico. “Wild yeast could mean a new flavor, a new aroma.”

But whatever yeast strain is the current favorite for a brewer, scientist, or beer-drinker, it matters less than the great blessing that is yeast. “If you have no yeast then you have no alcohol,” reminds McConico. “If you have no alcohol, then you have no beer.”


 

KNOW YOUR BEER TERMS 

Malt: Short for malted grains, usually barley, but could also be wheat, rye, or anything else. Soaking the barley allows it to germinate, then heating stops the process. This roasting stage has the first impact on flavor: light roasts might get turned into pale ales, golden ales, or pilsners. More and more roasting leads to darker and darker malts and darker and darker beers.

Wort: The brewer’s concoction of everything-but-the-alcohol. The malt has been mashed and heated so the starches in the grains are converted to sugar. Hops and any other ingredients have been added. Wort is hot and sweet and ready to be fermented into beer.

Hops: Famously bitter, hops can also give fruity, floral and other tastes to beer. The part of the hop plant, Humulus lupulus, that’s used in brewing is the flower, traditionally dried and available as pellets or occasionally “whole leaves” (don’t be fooled, these are still petals.) A popular trend is to “wet hop” a beer, which adds fresh instead of dried hops to the wort — Sierra Nevada’s Harvest Ale was the first wet hop IPA in 1996.

Wild or open-air fermentation: The beer tank is literally open to whatever might fall inside. Before Louis Pasteur and sterilization, all beer was made this way. Now, traditional beers are more controlled, while open-air fermentation is making a comeback because of the interesting flavors wild yeasts and bacteria can introduce.

Saccharomyces: The O.G. brewer’s yeast. S. cerevisiae is the most well-known, and is used in beers, wines, and breads worldwide. Hundreds of ale yeast strains are available that can give beers different flavors, with names like American Ale 1056 and Old Sonoma Ale WLP076. Lager yeast, S. pastoralis, is cold tolerant and is actually a hybrid between S. cerevisiae and its wild relative S. eubayanus, which was only found in the wild for the first time in 2011.

Brettanomyces: A yeast that ferments like Saccharomyces but is slightly less predictable, works slower, and is likely to give your beer a funky taste (good or bad — if you’re not making a sour, you might want to make sure to keep Brett out of your brew.)

Lactobacillus and Pediococcus: Not yeasts, but species of bacteria. Lacto and pedio eat the sugars in the wort, just like the yeasts do, but turn the sugars into lactic acid instead of alcohol. Lactic acid tastes sour: You might find it in a gose, lambic, Berliner weiss or Flanders red.

Wine: Technically referring to fermented grapes, the term also sometimes gets thrown around to describe beverages that are closer to beers but have higher alcohol contents. Examples include barley wine (really just a strong beer), honey wine (also known as mead, though it sometimes does have fruit or grains added, blurring the taxonomy) and rice wine (or sake — no grapes here.)

CATEGORIZED UNDER: Living World, Top Posts
MORE ABOUT: Food Science

The Light Triad: Psychologists Outline the Personality Traits of Everyday Saints

By Lacy Schley | April 5, 2019 10:15 am
(Credit: Melitas/Shutterstock)

(Credit: Melitas/Shutterstock)

If stories about psychopaths fascinate you, you might’ve heard of something called the dark triad. It’s a trio of traits that psychologists developed in the early 2000s to measure the more sinister aspects of human personality. Now, a team from the University of Pennsylvania and the University of Hawai’i-West O’ahu has finally crafted a counterpart test of the so-called light triad traits.

Read More

CATEGORIZED UNDER: Mind & Brain, Top Posts
MORE ABOUT: psychology

Why Do Humans Have Wisdom Teeth That Need to Be Removed?

By Bridget Alex | April 3, 2019 12:54 pm
wisdom teeth

(Credit: Dooder/Shutterstock)

Wisdom teeth seem like a biological mishap. Our third and final set of molars to grow, wisdom teeth don’t quite fit in many people’s mouths, leading to millions of surgeries per year. But in some people, these “extra” teeth come in just fine, while others don’t have them at all.

What’s the biological story here?

First let’s establish what’s probably not the story: Conventional wisdom about wisdom teeth assumes evolution was doing away with these unnecessary chompers until modern medicine halted the process. Read More

The Grandmother Hypothesis Could Explain Why Women Live So Long

By Bridget Alex | April 1, 2019 1:00 pm
grandmother

The grandmother hypothesis states that women live well past menopause so that they can help raise successive generations of children. (Credit: Goran Bogicevic/Shutterstock)

From an evolutionary perspective, the point of life is to procreate and pass on genes. That’s why most animals keep reproducing until their deathbeds.

Yet in humans, females tend to live for decades after they’re no longer fertile. All around the world, women experience menopause at around age 50 and routinely continue living into their 70s or 80s. Read More

CATEGORIZED UNDER: Living World, Top Posts

Despite Passenger Fears, Automation is the Future of Aviation

plane pilots

Human pilots, surrounded by automation. (Credit: Sorbis/Shutterstock)

In the wake of the Lion Air and Ethiopian Airlines crashes of Boeing 737 Max planes, people are thinking about how much of their air travel is handled by software and automated systems – as opposed to the friendly pilots sitting in the cockpit.

Older commercial airliners, such as the Beechcraft 1900, which are still in service mostly as small commuter aircraft, often do not have any autopilot installed. By contrast, modern commercial airliners have automated systems that can augment or even replace pilots’ performance, managing engine power, controlling and navigating the aircraft, and in some cases, even completing landings.

Investigations are probing the possible role of automated systems in the 2018 Lion Air Flight 610 crash in Indonesia and the Ethiopian Airlines Flight 302 crash in March 2019. Regardless of those findings, the public may not know how much automation already is part of flying today – nor how much more automated commercial flight will become in the years ahead.

Our research has examined consumers’ willingness to interact with automated systems on all types of vehicles, including aircraft. Most recently, we have begun looking into people’s interest in what is being called “urban air mobility.” This concept involves a system of small two- to four-passenger fully autonomous air taxis that could carry passengers on short trips throughout cities without a human pilot on board.

Side Effects of Highly Automated Systems

One problem that arises in planes that have highly automated systems is that the pilots can lose track of what’s actually happening. This is presumably what happened in 2009 when Air France Flight 447 crashed in the Atlantic Ocean on its way from Rio de Janeiro to Paris. Airspeed sensors failed, causing the autopilot to turn itself off, but the pilots weren’t able to figure out what was happening or how to recover.

Some experts also believe that a pilot’s lack of awareness was a factor in the 2009 crash of Colgan Air Flight 3407 outside Buffalo, New York. While approaching the landing, pilots may have missed the fact that the plane was slowing down too much, and again didn’t realize what was happening until it was too late.

Pilots who spend a lot of time in the cockpits of planes with highly automated systems may also lose some sharpness at flying planes on their own. The average pilot of a Boeing or Airbus commercial plane manually flies the plane for between three and six minutes of the whole flight – mostly around takeoff, the initial climb to about 1,500 feet, and then landing.

Industry Supports Automation

Airlines and manufacturers say they would save money and alleviate the current shortage of qualified pilots if they could reduce – or even eliminate – the number of pilots in the cockpit. Redesigning the front of the aircraft to be more aerodynamic could save even more money, if it didn’t need to have room for pilots, or could move them to another part of the aircraft.

Several companies are developing fully autonomous aircraft, including Amazon and UPS, which want to use them for deliveries. Boeing and Airbus are designing self-flying air taxis, which would be used for flights of about 30 minutes and carry between two and four passengers, and have tested prototypes. A company called Volocopter has been testing autonomous air taxis in Germany since 2016 and plans to conduct test flights in downtown Singapore this year. Ridesharing giant Uber, helicopter maker Bell and many other companies are also expressing interest in similar vehicles.

Consumer Willingness to Fly in Autonomous Aircraft

No matter how far industry progress goes, the key to autonomous flight will be its customers. We have been among the scholars who have studied how willing people are to fly in self-piloting aircraft.

Most of the results suggest that consumers don’t know how much of aviation is already automated. Survey participants tend to think pilots fly manually much more than they actually do.

In a study we conducted in 2014, people were much more willing to fly in planes with a human pilot in the cockpit – and quite unwilling to fly with either a human flying the plane remotely or aboard a fully autonomous plane.

 

 

Of course, some consumers are willing to fly in fully autonomous aircraft. In a larger study in 2018, just under 30 percent of U.S. consumers indicated they would be willing to fly on an autonomous airliner. These are the early adopters, who tend to be people who are familiar with automation and view flying on an autonomous airliner as a fun activity. People who are happy about the prospect of increased automation also tend to be more willing to fly on smaller autonomous air taxis.

However, most people are not ready to take fully autonomous commercial flights. Approximately 60 percent of passengers in our study said they were unwilling to fly on an autonomous commercial airliner.

We believe that lack of knowledge about automation is one of the critical factors here, and that the public would feel better about automated flying if they knew more about the benefits of automation – such as extremely reliable automated warning systems to prevent mid-air collisions and crashes.

What the Future Entails

Automation is not going away. In fact, by all accounts, it is becoming more prevalent in the cockpit. We fully expect autonomous flights to become commonplace in the next few decades.

Despite the notable crashes involving autopilots, the industry as a whole appears to believe that the automation of the future will be safe, or at least safer, for the flying public. Human error remains the most common cause of aircraft accidents, and people are prone to make the same mistakes again. They also may have trouble taking over from automation if the computers run into problems. Automated systems, however, can be reprogrammed not to make the same errors a second time.

Large commercial airplanes will likely go pilotless later than smaller private aircraft, because of the amount of time and money required to produce them. But smaller air taxis simply are not economically viable if they require a human pilot on board. As aviation automation engineering and technology continues to advance toward full automation, companies and customers alike will need to evaluate the risks and benefits, financially, in terms of safety – and emotionally.The Conversation

 

This is a guest post from Stephen Rice, Associate Professor of Human Factors, Embry-Riddle Aeronautical University and Scott Winter, Assistant Professor of Graduate Studies, Embry-Riddle Aeronautical University. This piece reflects the views of the authors.

Disclosure Statement: Stephen Rice has received funding from the United States Air Force and the Federal Aviation Administration. Scott R. Winter has received funding from the Federal Aviation Administration and Department of Transportation. The opinions in this article are solely the opinions of the authors.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

CATEGORIZED UNDER: Technology, Top Posts

Drink Your Beets: The Science Behind the Vegetable’s Surprising Benefits

By Rodrigo Pérez Ortega | March 26, 2019 5:04 pm
beet juice

(Credit: 5 second Studio/Shutterstock)

Carnitine, chromium, anabolic steroids: Athletes have experimented with a broad array of aids in pursuit of a performance edge. A popular — if unglamorous — one today that seems safe and backed by solid data: the juice of beets, for the nitrate it contains.

Inorganic nitrate (NO3) is added to cured and processed meats to extend their shelf life and give them their distinctive pink color. It’s also naturally found in spinach, arugula and beets. In the past decade, new evidence has suggested that the nitrate in these vegetables enhances athletic performance and may also increase cardiovascular health in old age.

The first clue came in 2007, when Swedish researchers reported that three days of sodium nitrate supplementation lowered the oxygen demand of nine cyclists and triathletes as they worked out, compared with a placebo of table salt. It also increased the blood plasma levels of nitrite (NO2), a byproduct of nitrate. That study caught the eye of exercise physiologist Andrew Jones of the University of Exeter in England. Usually, the oxygen demand of exercise is fixed, he says, so for a short-term intervention to change that “was unusual.”

Although it wasn’t clear how nitrate was doing what it did, Jones knew that green leafy vegetables and beets were rich sources. So he conducted a study, reported in the Journal of Applied Physiology, giving eight men active in recreational sports an equivalent amount of nitrate in a natural food source: beet juice. The volunteers consumed 500 ml (17 oz) of either beet juice or a black currant drink — which has negligible amounts of nitrate — every day for six days. Then, after a break of 10 days, the groups were switched and consumed the other drink for an additional six days.

By the last three days of the six, nitrate concentration in the blood of those drinking beet juice was almost doubled and their systolic blood pressure fell by an average of 6 mm Hg. The oxygen cost — the amount of oxygen consumed — when they exercised on a stationary bicycle was reduced by 19 percent. “When we asked them to continue to exercise to exhaustion, they were able to go longer,” recalls Jones, who coauthored a review on dietary nitrates in the 2018 Annual Review of Nutrition.

From then on, research on beet juice, beet juice concentrates, whole beets and nitrate salts started to pour in.

From Food to Fuel

Nitrate itself doesn’t do much in the body. It first has to be converted to nitric oxide, a gas with numerous physiological roles — in blood vessel dilation, muscle contraction and transmission of nerve signals, among others. People obtain that nitric oxide in two ways: either through the action of the enzyme nitric oxide synthase, which catalyzes the amino acid L-arginine to produce it, or from nitrate ingested in food.

In the second case, dietary nitrate is first reduced to nitrite by bacteria in our mouths (athletes are counseled to avoid mouthwash, toothpaste and antibiotics before these kinds of studies). And then, over the next several hours, some of the nitrite is further reduced to nitric oxide in the gut. Nitrite also enters the blood and bodily tissues, where it is enzymatically reduced to nitric oxide.

beets performance

This chart shows how dietary nitrate can act to enhance athletic performance. Although nitrate itself is not physiologically active, it is ultimately converted to nitric oxide, which can improve muscle and cardiovascular function through a variety of effects on the body.

Scientists know that this second route is enhanced under conditions when there is not enough oxygen in muscles, and when acid builds up — exactly what happens in skeletal muscle when it contracts constantly during exercise. So they hypothesize that this pathway is particularly important during exercise as a backup system to ensure that enough nitric oxide gets made in muscles and other tissues.

Once in skeletal muscle, nitric oxide can do several things. It can improve the efficiency of muscle contraction and of energy generation by mitochondria. Both of these could contribute to the lowered oxygen cost of exercise. So could the gas’s property of dilating blood vessels, as it increases blood flow to muscle.

Passing the Test

Studies testing the effects of dietary nitrate in different sports are piling up. Beet juice is the preferred method of administration, since it’s a fluid and measuring the nitrate levels in it is easy. (“It’s just more convenient,” says Jones.)

In a 2011 study in Medicine & Science in Sports & Exercise, for example, Jones and his team asked nine competitive male cyclists to drink 500 ml of beetroot juice containing almost 400 mg of nitrate, 2.5 hours before starting a 4 or 16.1 km cycling endurance test. Researchers found that the men who drank beet juice improved their performance by 2.7 percent in the 4 km test and 2.8 percent in the 16.1 km test, compared to men who drank a nitrate-depleted beet juice.

In another study, published in 2015 in the International Journal of Sport Nutrition and Exercise Metabolism, Australian researchers gave five professional female kayakers two 70 ml (2.4 oz) shots of beet juice, each containing about 300 mg of nitrate, two hours before a 500-meter kayak test. Compared to a placebo, the rowers who drank beet juice improved their performance by 1.7 percent.

After many such experiments, mainly with runners and cyclists, researchers have concluded that nitrate supplementation lowers the oxygen demand of exercise and improves performance in endurance sports. They find that beet juice is most effective when drunk two to three hours before exercise and, in general, that 300 to 500 mg of inorganic nitrate is enough to provide a 1 to 3 percent improvement in performance — significant enough to give a serious athlete a competitive edge. Solid vegetables, though they’re not generally used in such studies, can be effective, too: Beetroot and spinach contain more than 250 mg of nitrate per 100 g (3.5 oz) of produce.

dietary nitrite

Here’s a roundup of studies looking at dietary nitrate’s effects on performance for elite and recreational athletes. Both short-term (acute) and longer-term (chronic) regimens were tested. Results that reached statistical significance are marked by an asterisk. Recreational athletes may gain more from nitrate supplementation than highly trained athletes; other potential factors are the dose and duration of nitrate supplementation as well as the duration, intensity and type of exercise.

“What intrigues me the most, I think, is the fact that a simple dietary intervention can have these significant effects,” says Andrew Coggan, an exercise physiologist at Indiana University – Purdue University Indianapolis. “And then to think that is having a direct and quantifiable impact on our muscle function is rather striking.”

While the immediate effects of nitrate on endurance are clear, researchers don’t yet know whether steadily drinking beet juice over days has stronger effects. So far, the evidence is mixed.

Researchers are also eager to know whether the juice offers an edge in other types of “explosive” sports, where power and strength are key. Sports nutrition researcher Raúl Domínguez of University Isabel I in Spain recently reported in the journal Nutrients that 70 ml of beet juice concentrate improved the performance of 15 volunteers in a 30-second cycling sprint. Though there’s still more work to be done, “it seems that we can use it in all modalities,” Domínguez says.

The Business Side of Beets

Though the flavor’s not to everyone’s taste (Coggan refers to it as “sweet dirt”), the hype for beet juice has grown with every new study, and one can now find plenty of beet juices, concentrates, energy bars, capsules and powders that promise, or imply, enhanced performance. The International Olympic Committee’s acknowledgement last year that beet juice is a sports food with good scientific evidence to back it — along with other ergogenic aids, or endurance enhancing supplements, such as caffeine, creatine and sodium bicarbonate — has only fueled beet juice enthusiasm.

But because these products are not regulated by the US Food and Drug Administration, consumers often can’t know for sure how much nitrate they contain. Last year, Coggan and an undergraduate tested 24 products, from powders to concentrates and bulk juice, and found that only five contained effective levels of nitrate.

Some companies are adding pure nitrate salts to sports drinks and supplements, “which is scary to me,” says sports nutritionist Edward Weiss from Saint Louis University in Missouri. He strongly recommends using the juice instead of the salts. “There’s a lot of plant chemicals that prevent the conversion of the nitrate into a carcinogen that we know about, called nitrosamine,” he says.

What is more, says Domínguez, studies suggest that the benefits of dietary nitrate are larger when they’re ingested in beets and other vegetables, and not as salts — mainly due to the vegetables’ vitamin C and polyphenols, which help reduce the nitrite to nitric oxide in the stomach.

Not Just for Athletes

Dietary nitrate has done more than start a little revolution in the sports world. Now scientists are looking at its effect in other populations, too. Coggan says that after he read about the studies with athletes, he thought: “If there was any patient population out there that could benefit from getting the most bang from their buck, it would be heart-failure patients.” Could beet juice enhance the heart’s ability to deliver oxygen-carrying blood, and help keep the skeletal muscle strong, in such patients?

In a 2015 study reported in the journal Circulation, Coggan and colleagues reported that giving beet juice to nine patients with heart failure increased the nitric oxide levels in their breath by as much as 50 percent and their knee muscle power by as much as 11 percent, as measured with a dynamometer. That difference might improve patients’ quality of life by enabling them to more easily perform day-to-day activities such as getting out of a chair. Researchers are now looking at the potential therapeutic benefits of dietary nitrate in elderly people, as well as in those who have diabetes, obesity and hypertension.

For Coggan, the fact that a single component of a healthy diet can have such a clear effect is startling. “And then you start to wonder about — well, what other components of our diet are having measurable effects, and people just haven’t made the link yet?”

 

Read More

CATEGORIZED UNDER: Health & Medicine, Top Posts
MORE ABOUT: nutrition
NEW ON DISCOVER
OPEN
CITIZEN SCIENCE
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

ADVERTISEMENT

See More

ADVERTISEMENT
Collapse bottom bar
+