A Famous Argument Against Free Will Has Been Debunked



The death of free will began with thousands of finger taps. In 1964, two German scientists monitored the electrical activity of a dozen people’s brains. Each day for several months, volunteers came into the scientists’ lab at the University of Freiburg to get wires fixed to their scalp from a showerhead-like contraption overhead. The participants sat in a chair, tucked neatly in a metal tollbooth, with only one task: to flex a finger on their right hand at whatever irregular intervals pleased them, over and over, up to 500 times a visit.

The purpose of this experiment was to search for signals in the participants’ brains that preceded each finger tap. At the time, researchers knew how to measure brain activity that occurred in response to events out in the world—when a person hears a song, for instance, or looks at a photograph—but no one had figured out how to isolate the signs of someone’s brain actually initiating an action.

The experiment’s results came in squiggly, dotted lines, a representation of changing brain waves. In the milliseconds leading up to the finger taps, the lines showed an almost undetectably faint uptick: a wave that rose for about a second, like a drumroll of firing neurons, then ended in an abrupt crash. This flurry of neuronal activity, which the scientists called the Bereitschaftspotential, or readiness potential, was like a gift of infinitesimal time travel. For the first time, they could see the brain readying itself to create a voluntary movement.

This momentous discovery was the beginning of a lot of trouble in neuroscience. Twenty years later, the American physiologist Benjamin Libet used the Bereitschaftspotential to make the case not only that the brain shows signs of a decision before a person acts, but that, incredibly, the brain’s wheels start turning before the person even consciously intends to do something. Suddenly, people’s choices—even a basic finger tap—appeared to be determined by something outside of their own perceived volition.

As a philosophical question, whether humans have control over their own actions had been fought over for centuries before Libet walked into a lab. But Libet introduced a genuine neurological argument against free will. His finding set off a new surge of debate in science and philosophy circles. And over time, the implications have been spun into cultural lore.

Today, the notion that our brains make choices before we are even aware of them will now pop up in cocktail-party conversation or in a review of Black Mirror. It’s covered by mainstream journalism outlets, including This American Life, Radiolab, and this magazine. Libet’s work is frequently brought up by popular intellectuals such as Sam Harris and Yuval Noah Harari to argue that science has proved humans are not the authors of their actions.

It would be quite an achievement for a brain signal 100 times smaller than major brain waves to solve the problem of free will. But the story of the Bereitschaftspotential has one more twist: It might be something else entirely.

Trampoline mirror may push laser pulse through fabric of the Universe



Scientists want to rip the Universe apart. At least that is what a Daily Mail headline might read. Lasers can now reach power in the petawatt range. And, when you focus a laser beam that powerful, nothing survives: all matter is shredded, leaving only electrons and nuclei.

But laser physicists haven’t stopped there. Under good experimental conditions, the very fabric of space and time are torn asunder, testing quantum electrodynamics to destruction. And a new mirror may be all we need to get there.

On average, the amount of power used by humans is about 18 terawatts. A petawatt is 1,000 times larger than a terawatt. The baddest laser on the planet (currently) produces somewhere between 5 and 10 petawatts, and there are plans on the drawing board to reach 100 petawatts in the near future. The trick is that the power is not available all the time. Each of these lasers produces somewhere between 5-5000 J of energy for a very, very short time (between a picosecond—10-12s—and a few femtoseconds—10-15s). During that instant, however, the power flow is immense.

The numbers get even more mind-blowing when you consider that all of that energy is focused, such that the intensities reach something like 1022W/cm2. To put this in perspective, you start creating a plasma when intensities hit 1012W/cm2. Once intensities get above 1025W/cm2, if the light hits just a single electron, there's enough energy to start a cascade of electron-positron production out of the vacuum. If the laser intensity hits 1029W/cm2, not even that single electron is required—the light will rip virtual electrons out of the vacuum, generating real charges from the apparent nothingness of empty space.

But getting to 1025W/cm2 is tough. The issue is one of material. Or, rather it's the lack of a material that can survive long enough to focus the laser light. This is where plasma mirrors come in.

Plasma mirrors were all the rage a few years ago when petawatt lasers were all fresh and new. The idea is actually very simple. A plasma is a gas of conducting particles, with its electrons being very light and easy to move around. When light hits the plasma, the electrons are accelerated back and forth, following the light’s electric field. In doing so, the electrons absorb and re-emit the light in the opposite direction. In other words, the light reflects from the plasma, just like it does from a chrome bumper.

A plasma is basically already as destroyed as a material can be, so the laser beam cannot damage the plasma.

. . .

The end result is a factor of 1,000 higher intensity for the same input laser and a simple mirror swap. That is pretty cool.

DNA tests reveal what's living in Yukoner's 120-year-old sourdough starter



Ione Christensen pulls a small Tupperware from her fridge at home in Whitehorse. The container is beaten up and the contents look like a paste that may have gone bad. It looks questionable, even a little cruddy.

Inside is something special — a 120-year-old sourdough starter.

A label on the container reads, "DO NOT THROW OUT."

"The reason I do that is because if we're going away, well, we don't go away in the holidays anymore, but when we used to and someone was looking after the house, you don't want them cleaning out the fridge before you come home and say, 'that's a horrible looking thing,'" said Christensen, a former Yukon senator.

The starter has been in Christensen's family since the 1898 Klondike Gold Rush, when her great-grandfather travelled to Dawson City via the Chilkoot Trail.

A year ago, part of Christensen's prized starter got packed up in a special box and shipped to Saint-Vith, Belgium, to become sample 106 in the Puratos Sourdough Library.

Some of the starter has gone on display in the library, and tests were also done to find out what microorganisms are thriving in the sourdough that Christensen, 85, uses each weekend to make fluffy and flavourful waffles and hot cakes.

17 science 'facts' you might've learned in school that aren't true

Science is an ongoing process, which means new discoveries often upend old theories.

. . .

If you were to file into a classroom and open your notebook for science class today, the subject matter might be a little different from when you were in school.

Science is a body of knowledge that's constantly growing and changing. New discoveries or studies often lead to changes in old theories and sometimes even invalidate them altogether. That means some of the "facts" you learned in school aren't necessarily true anymore.

For example, dinosaurs probably didn't look the way your textbook depicted them. The origins of Homo sapiens aren't as neat as the timeline you might have learned. And many of the nutrition and exercise guidance from your health classes has been debunked.

Here are some science facts you may have learned in school that aren't true anymore.
Myth: We don't know what caused the dinosaurs' mass extinction.
An artist's impression of a 6-mile-wide asteroid striking the Earth. This type of cosmic impact, near what is now the town of Chicxulub in Mexico, ended the age of dinosaurs. Don Davis

Scientists used to scratch their heads about what caused the extinction that ended the age of dinosaurs — theories ranged from low dino sex drives to a world overrun by caterpillars.

But in 1978, geophysicists stumbled upon Chicxulub, a crater in the Yucatan Peninsula made by the 6-mile-wide asteroid that likely triggered the dinosaurs' demise.

Since that discovery, researchers have uncovered more details about the asteroid's impact. The collision caused a mile-high tsunami, sparked wildfires, and released billions of tons of sulfur into the atmosphere, blotting out the sun for years.
But the asteroid may not be the full explanation.
Lava fragments fall from lava fountains during an eruption of the Kilauea volcano in Hawaii in June 2018. USGS via Reuters

Some scientists argue that volcanic eruptions in modern-day India also contributed to the dinosaurs' downfall.
Myth: Dinosaurs were scaly, earthy-colored lizards.
A model of a feathered tyrant on display at the "Dinosaurs Among Us" exhibit at the American Museum of Natural History in New York in March 2016. AP Photo/Mary Altaffer

Dinosaurs — even the Tyrannosaurus rex — likely had feathers.

Feathers are rarely preserved in the fossil record, but scientists have uncovered feathered dino fossils in China and Siberia, suggesting plumage was common across the great lizards.

"Probably that means the common ancestor of all dinosaurs had feathers," Pascal Godefroit, a paleontologist who wrote a 2014 study on a key Siberian fossil, told National Geographic.

Underneath the feathers, dinos could have had brightly colored scales, like many modern-day lizards.
Feathers have never been found on a T. rex specimen, but fossils of other tyrannosaur species do have preserved feathers. So paleontologists can assume the T. rex had them too.
A life-size model of a T. rex with patches of feathers — the most scientifically accurate representation to date — at the American Museum of Natural History exhibit "T. rex: The Ultimate Predator." D. Finnin/American Museum of Natural History

Though adult T. rexes were mostly covered in scales, scientists think they had patches of feathers on attention-getting areas like the head and tail.

. . .

The ozone layer is on track to completely repair itself in our lifetime

The ozone layer is steadily repairing itself following a drastic global reduction in the use of ozone-depleting substances, the UN's environmental agency has found.

The world's ozone layer is on track to be completely healed by the 2060s, according to modelling by the UN's environmental agency (UNEP).

In the past 19-years, parts of the ozone layer have recovered at a rate of one to three per cent every ten years, UNEP has found. If this continues, the Northern Hemisphere's ozone layer is set to heal completely by the 2030s, the Southern Hemisphere by the 2050s, and the polar regions in the following decade.

Microplastics in the Great Lakes: Becoming benthic



From the Great Pacific garbage patch to inland rivers, plastics are among the most widespread contaminants on Earth. Microplastics—particles of plastic smaller than five millimeters—are especially pervasive. As they build up in Earth's waters, microplastics are also becoming a permanent part of the planet's sedimentary layers.

Now, using the Great Lakes as a laboratory, sedimentary petrologist Patricia Corcoran and her students at the University of Western Ontario are studying the behavior of microplastics as a geologic phenomenon.

What are the main sources of microplastics to Great Lakes sediment? What factors influence their distribution, and where do they concentrate? To explore these questions, and shed light on implications such as which animals may be at risk from microplastics, Corcoran's team has analyzed offshore and nearshore sediment samples from Lakes Huron, Ontario, Erie, and St. Clair, and their tributaries. Abundances were as high as 4270 microplastics particles per kilogram of dry weight sediment in lake sediment, and up to 2444 microplastic particles per kilogram in river sediment.

The team found that the more organic debris in the sample, the more microplastics. Benthic microplastics—those incorporated into lake bottom sediments—were also more abundant near high population areas, which are also associated with plastics industry locations.

Biruté Galdikas is a famous primatologist that you’ve probably never heard of

With the mention of primates and those who have dedicated their lives to the study of them, people often think of Dian Fossey and Jane Goodall. But neither of these women can be credited with operating the longest continuous study by one principal investigator of any wild mammal in the world.

That honour goes to Biruté Galdikas, a Canadian scientist, conservationist and educator who is surprisingly less known than her fellow Trimates, Goodall and Fossey. She Walks with Apes, a new documentary from The Nature of Things, tells the story of the Trimates and the next generation of women who were inspired to live with the great apes.

Ruth Linsky, one young scientist featured in the film, is an Alberta native who studied biology, ecology and evolution at Simon Fraser University in B.C., where Galdikas teaches. Linsky, Gladikas’s current mentee, hadn’t heard of the renowned primatologist until a friend recommended taking one of her courses.

“Growing up, I saw Gorillas in the Mist, so I knew about Dian Fossey,” Linsky says, “and Jane Goodall is just, like, a household name. [But] I didn’t even know about Dr. Galdikas until I met her at Simon Fraser,” she remembers. “I looked [her] up and was just blown away that this lady was a professor at the school, and I had no idea.”
Galdikas, a living legend

Biruté Galdikas was born en route to Canada from her parents’ homeland, Lithuania, and raised in Toronto. She discovered her love of animals and adventure at a young age after reading Curious George, and dreamed about becoming an explorer.

She went on to study at the University of British Columbia and then, after her family moved to the United States, UCLA. There, Galdikas studied psychology, zoology and anthropology, and met Louis Leakey, a famed paleoanthropologist who had worked with Fossey and Goodall to enable them to study apes in the wild.

Galdikas had been told by professors and peers that it would be impossible to study wild orangutans because they were elusive and lived almost exclusively in habitats that were swampy and remote, and therefore difficult for humans to navigate. But she was determined, and with financial help from Leakey, she headed to Borneo in Indonesia.

She established Camp Leakey in 1971, and it now functions as a base for research scientists, students, staff members and park rangers.

Climate change: Scientists to report on ocean 'emergency' caused by warming

Lab-made primordial soup yields RNA bases






Single strand ribonucleic acid, RNA research and therapy.

RNA has been synthesized in conditions that may have resembled those on the early Earth.Credit: Alamy

If Thomas Carell is right, around 4 billion years ago, much of Earth might have been blanketed with a greyish-brown kind of mineral. This was no ordinary rock, however: it consisted of crystals of the organic molecules that scientists now call A, U, C and G. And some of these, the theory goes, would later serve as the building blocks of RNA, the evolutionary engine of the first living organisms, before DNA existed.

Carell, an organic chemist, and his collaborators have now demonstrated a chemical pathway that — in principle — could have made A, U, C and G (adenine, uracil, cytosine and guanine, respectively) from basic ingredients such as water and nitrogen under conditions that would have been plausible on the early Earth. The reactions produce so much of these nucleobases that, millennium after millennium, they could have accumulated in thick crusts, Carell says. His team describes the results in Science on 3 October1.

The results add credence to the ‘RNA world’ hypothesis, says Carell, who is at the Ludwig Maximilian University of Munich in Germany. This idea suggests that life arose from self-replicating, RNA-based genes — and that only later did organisms develop the ability to store genetic information in the molecule’s close relative, DNA. The chemistry is also a “strong indication” that the appearance of RNA-based life was not an exceedingly lucky event, but one that is likely to happen on many other planets, he adds.

In previous work in 2016, Carell’s team had found chemical reactions that spontaneously yielded the nucleobases A and G2. A separate group had done a similar proof-of-principle3 for the other two, U and C in 2009. But the two pathways seemed incompatible with each other, requiring different conditions, such as divergent temperatures and pH.

Now, Carell’s team has shown how all nucleobases could form under one set of conditions: two separate ponds that cycle through the seasons, going from wet to dry, from hot to cold, and from acidic to basic, and with chemicals occasionally flowing from one pond to the other. The researchers first let simple molecules react in hot water and then allowed the resulting mix to cool down and dry up, forming a residue at the bottom that contained crystals of two organic compounds.

They then added water back, and one of the compounds dissolved and was washed away into another reservoir. The absence of that water-soluble molecule allowed the other compound to undergo further reactions. The researchers then mixed the products again, and their reactions formed the nucleobases.

“This paper has demonstrated marvellously the chemistry that needs to take place so you can make all the RNA nucleosides,” says Ramanarayanan Krishnamurthy, a chemist at Scripps Research in La Jolla, California. But he and other researchers often warn that this and similar results are based on hindsight and might not offer credible guidance as to how life actually evolved.

Cows painted with zebra-like striping can avoid biting fly attack


journal.pone.0223447.g002.PNG [ 4.27 MiB | Viewed 109 times ]

Abstract

Experimental and comparative studies suggest that the striped coats of zebras can prevent biting fly attacks. Biting flies are serious pests of livestock that cause economic losses in animal production. We hypothesized that cows painted with black and white stripes on their body could avoid biting fly attacks and show fewer fly-repelling behaviors. Six Japanese Black cows were assigned to treatments using a 3 × 3 Latin-square design. The treatments were black-and-white painted stripes, black painted stripes, and no stripes (all-black body surface). Recorded fly-repelling behaviors were head throw, ear beat, leg stamp, skin twitch, and tail flick. Photo images of the right side of each cow were taken using a commercial digital camera after every observation and biting flies on the body and each leg were counted from the photo images. Here we show that the numbers of biting flies on Japanese Black cows painted with black-and-white stripes were significantly lower than those on non-painted cows and cows painted only with black stripes. The frequencies of fly-repelling behaviors in cows painted with black-and-white stripes were also lower than those in the non-painted and black-striped cows. These results thus suggest that painting black-and-white stripes on livestock such as cattle can prevent biting fly attacks and provide an alternative method of defending livestock against biting flies without using pesticides in animal production, thereby proposing a solution for the problem of pesticide resistance in the environment.

Engineers put Leonardo da Vinci’s bridge design to the test







Proposed bridge would have been the world’s longest at the time; new analysis shows it would have worked.

In 1502 A.D., Sultan Bayezid II sent out the Renaissance equivalent of a government RFP (request for proposals), seeking a design for a bridge to connect Istanbul with its neighbor city Galata. Leonardo da Vinci, already a well-known artist and inventor, came up with a novel bridge design that he described in a letter to the Sultan and sketched in a small drawing in his notebook.

He didn’t get the job. But 500 years after his death, the design for what would have been the world’s longest bridge span of its time intrigued researchers at MIT, who wondered how thought-through Leonardo’s concept was and whether it really would have worked.

Spoiler alert: Leonardo knew what he was doing.

To study the question, recent graduate student Karly Bast MEng ’19, working with professor of architecture and of civil and environmental engineering John Ochsendorf and undergraduate Michelle Xie, tackled the problem by analyzing the available documents, the possible materials and construction methods that were available at the time, and the geological conditions at the proposed site, which was a river estuary called the Golden Horn. Ultimately, the team built a detailed scale model to test the structure’s ability to stand and support weight, and even to withstand settlement of its foundations.

Paris zoo unveils the "blob", an organism with no brain but 720 sexes

PARIS (Reuters) - A Paris zoo showcased a mysterious new organism on Wednesday, dubbed the “blob”, a yellowish unicellular small living being which looks like a fungus but acts like an animal.

This newest exhibit of the Paris Zoological Park, which goes on display to the public on Saturday, has no mouth, no stomach, no eyes, yet it can detect food and digest it.

The blob also has almost 720 sexes, can move without legs or wings and heals itself in two minutes if cut in half.

“The blob is a living being which belongs to one of nature’s mysteries”, said Bruno David, director of the Paris Museum of Natural History, of which the Zoological Park is part.

“It surprises us because it has no brain but is able to learn (...) and if you merge two blobs, the one that has learned will transmit its knowledge to the other,” David added.