Amazing Science

Sandia's Z machine uses electricity to create radiation and high magnetic pressure, which are both applied to a variety of scientific purposes ranging from weapons research to the pursuit of fusion energy.

The process starts with wall-current electricity, which Z uses to charge large capacitors — structures designed to store an electric charge and release it instantaneously. In every shot the machine consumes only about as much energy as it would take to light 100 homes for a few minutes. Metal cables arranged like the spokes of a wheel connect the capacitors to a central vacuum chamber, 10 feet in diameter and 20-feet high. The cables, some insulated by water and some by oil, are each as big around as a Volkswagen Beetle and 30-feet long.

When the accelerator fires, powerful electrical pulses strike a target at the center of the machine. Each shot from Z carries more than 1,000 times the electricity of a lightning bolt, and is 20,000 times faster. The target is about the size of a spool of thread, and it consists of hundreds of tungsten wires, each thinner than a human hair, enclosed in a small metal container known as a Hohlraum (German for hollow space). The hohlraum serves to maintain a uniform temperature.

The flow of energy through the tungsten wires dissolves them into plasma and creates a strong magnetic field that forces the exploded particles inward. The speed at which the particles move is equivalent to traveling from Los Angeles to New York – about 3,000 miles – in slightly less than one second. The particles then collide with one another along the z axis (hence the name Z machine), and the collisions produce intense radiation (2 million joules of X-ray energy) that heats the walls of the hohlraum to approximately 1.8 million degrees Celsius.

Instruments that measure these implosions must be even faster in order to record the details of the process. This is an added challenge for researchers who rely on the accuracy of these measurements to understand Z's results and nuclear events in general. Accurate measurements allow scientists to experiment with a variety of target arrangements to create conditions useful for many different purposes.

Machines and devices used in modern industry are required to withstand harsh conditions. When the environmental temperature changes, the volume of the materials used to make these devices usually changes slightly, typically by less than 0.01%. Although this may seem like a trivial change, over time this thermal expansion can seriously degrade the performance of industrial systems and equipment.

Materials that contract on heating, or negative thermal expansion materials, are therefore of great interest to industrial engineers. These materials can be mixed with normal materials, which expand on heating, with the final aim of producing a composite material with its thermal expansion adjusted to a particular value, typically zero, and maintained even at the extremely low operating temperatures used in cryogenic and aerospace engineering.

In a new study published in Nature Communications, Nagoya University-led researchers report a reduced ruthenate ceramic material, made up of calcium, ruthenium and oxygen atoms, that shrinks by a record-breaking 6.7% when heated. This is more than double the current record for a negative thermal expansion material, and the bulk material expands again when it is cooled. The results may provide industrial engineers with a new class of composite materials that can be used to increase the accuracy of processes and measurements, to improve the stability of device performance, and to prolong device lifetimes.

Wish you had another hour in the day to get everything done? Just wait 200 million years, when days here on Earth will stretch to 25 hours. While we like to think of the Earth’s rotation as one of the few constants in this world, it’s anything but. For hundreds of millions of years, days have been growing longer and longer. The changes are small enough that our circadian clocks can’t detect them, but atomic clocks certainly can. According to the National Institute of Standards and Technology, which runs the United States’ atomic clocks, days today are longer than those a century ago by two milliseconds. Add that up over millions of years and you start to see real changes—days in the Jurassic period were only 23 hours long, for example.

Antarctic seabirds called skuas are so clever that they can recognize individual humans after seeing them only a few times. Some Korean researchers discovered this by messing with the birds’ nests and then waiting to get attacked. They’re either very brave or have never watched The Birds.

The study took place on Antarctica’s King George Island. The animals here didn’t evolve around humans. People have only been making appearances on the island since the 1950s or so. Today 10 countries have research stations on the island. Korea Polar Research Institute scientist Won Young Lee and his coauthors study brown skuas here, which are like big, dark-colored gulls.

In the winter of 2014–2015, researchers visited skua nests once a week to check on their eggs and chicks. They suspected that the birds could recognize them, and were unhappy about humans poking at their nests. If a skua wants you to go away, it will give not-so-subtle hints like attacking your head.

So the researchers set up an experiment. Starting in the fourth week of their study, two researchers visited each nest at a time. One of them, the “intruder,” had checked on the nest in previous weeks. The other, “neutral” researcher had never been to the nest before. As they approached the nest, the researchers recorded how close they could get before the birds attacked. Then they split up and walked in opposite directions, observing which person the birds chased after.

As the weeks went on, skuas attacked from greater distances. But they didn’t attack just anybody. All seven of the nesting pairs directed their attacks at the known intruder. The birds “reacted very aggressively” after five visits, the authors write, including kicking intruders in the head. They ignored the neutral humans.

Even though the researcher pairs wore identical clothing for their experiments, the skuas had no trouble spotting people who had fiddled with their nests in the past. The researchers don’t think the birds were using smell to tell them apart, since the site is windy. More likely, the birds relied on human facial features and body postures.

This is especially impressive since the birds evolved without ever seeing a human. There’s no reason they should have a natural ability to recognize us. Two other local bird species, sheathbills and Antarctic terns, don’t seem to discriminate between people.

The scientists chalk it up to “high cognitive abilities” on the part of brown skuas. In other words, they may just be especially smart. This makes sense; the birds are predators that have to be flexible to find their prey. Brown skuas have been seen chasing other large birds and taking their food. They’ll even steal drops of breast milk from nursing elephant seals. This is a bird you don’t want to cross—and after you do, you might want to wear a mask.

f you ask Jill Price to remember any day of her life, she can come up with an answer in a heartbeat. What was she doing on 29 August 1980? “It was a Friday, I went to Palm Springs with my friends, twins, Nina and Michelle, and their family for Labour Day weekend,” she says. “And before we went to Palm Springs, we went to get them bikini waxes. They were screaming through the whole thing.” Price was 14 years and eight months old.

What about the third time she drove a car? “The third time I drove a car was January 10 1981. Saturday. Teen Auto. That’s where we used to get our driving lessons from.” She was 15 years and two weeks old. The first time she heard the Rick Springfield song Jessie’s Girl? “March 7 1981.” She was driving in a car with her mother, who was yelling at her. She was 16 years and two months old.

Price was born on 30 December 1965 in New York City. Her first clear memories start from around the age of 18 months. Back then, she lived with her parents in an apartment across the street from Roosevelt Hospital in Midtown Manhattan. She remembers the screaming ambulances and traffic, how she used to love climbing on the living room couch and staring out of the window down 9th Avenue.

When she was five years and three months old, her family – her father, a talent agent with William Morris who counted Ray Charles among his clients; her mother, a former variety show dancer, and her baby brother – moved to South Orange, New Jersey. They lived in a three-storey, red brick colonial house with a big backyard and huge trees, the kind of place people left the city for. Jill loved it.

When she was seven years old, her father was offered a job with Columbia Pictures Television in Los Angeles. He spent a year commuting back and forth from California to New Jersey, until he and her mother decided to move the family out there in the spring of 1974. By 1 July 1974, when Jill was eight and a half, they were living in a rented house in Los Angeles. That was the day, she says, her “brain snapped”.

Price was the first person ever to be diagnosed with what is now known as highly superior autobiographical memory, or HSAM, a condition she shares with around 60 other known people. She can remember most of the days of her life as clearly as the rest of us remember the recent past, with a mixture of broad strokes and sharp detail. Now 51, Price remembers the day of the week for every date since 1980; she remembers what she was doing, who she was with, where she was on each of these days. She can actively recall a memory of 20 years ago as easily as a memory of two days ago, but her memories are also triggered involuntarily.

It is, she says, like living with a split screen: on the left side is the present, on the right is a constantly rolling reel of memories, each one sparked by the appearance of present-day stimuli. With so many memories always at the ready, Price says, it can be maddening: virtually anything she sees or hears can be a potential trigger.

Before Price, HSAM was a completely unknown condition. So what about the day she sent an email to a Dr James McGaugh at University of California, Irvine? That was 8 June 2000, a Thursday. Price was 34 years and five months old.

Dr. James McGaugh remembers that day too. At the time, he was director of UC Irvine’s Center for the Neurobiology of Learning and Memory, the research institute that he founded in 1983. In her email, Jill Price said that she had a problem with her memory. McGaugh responded almost immediately, explaining that he worked at a research institute and not a clinic, and that he’d be happy to direct her to somewhere she could find help.

Price’s reply was swift and unexpected. “Whenever I see a date flash on the television (or anywhere else for that matter), I automatically go back to that day and remember where I was, what I was doing, what day it fell on and on and on and on and on. It is non-stop, uncontrollable and totally exhausting … Most have called it a gift but I call it a burden. I run my entire life through my head every day and it drives me crazy!!!”

Humanity possesses the means to place probes into orbit around nearby stars. But do we have the patience?

Interstellar travel, a timeworn staple of science fiction, can already be science fact if one has cash to spare. For just $100 million or so, a customer could actually purchase a top-of-the-line commercial rocket and ride right out of the solar system. But patience would be key. If launched tomorrow toward the nearest port of call—Proxima b, a potentially habitable Earth-mass planet recently discovered in the triple star system of Alpha Centauri about four light-years away—that rocket would take 80,000 years to arrive.

Instead of spending $100 million on a slow boat to the stars, in April of last year the billionaire entrepreneur Yuri Milner announced he would use that same sum to forge a new path to Alpha Centauri within a human lifetime. Called Breakthrough Starshot, the initiative calls for largely abandoning rockets in favor of “light sails”—gossamer-thin reflective sheets that, once unfolded in space, could be propelled to very high speeds by laser beams.

Starshot’s tentative plans involve using conventional rockets to place thousands of one-gram, four-meter-wide light sails in Earth orbit as early as the 2040s. Each sail would be embedded with a one-centimeter-wide chip containing cameras, sensors, thrusters and a battery. From Earth orbit, each featherweight spacecraft would be boosted toward Alpha Centauri at 20 percent light-speed by a minutes-long pulse from a ground-based, 100-gigawatt laser array. The interstellar crossing would take just a little over 20 years, so the probes could reach Alpha Centauri in the 2060s.

It wields sea anemones like boxing gloves; if it loses one, it makes another by bisecting the remaining one.

The American novelist S. E. Hinton once said, “If you have two friends in your lifetime, you’re lucky. If you have one good friend, you’re more than lucky.” By that logic, boxer crabs are the luckiest creatures alive because they can turn one good friend into two by tearing it in half.

These tiny, inch-long crabs carry sea anemones, holding them in place with special hooks on the inner edges of their claws. With their crowns of wavy tentacles, the anemones look like pom-poms, and the crabs like cheerleaders. But those tentacles also pack powerful stings, and a quick jab from them is often enough to ward off an attacking fish. Hence the name: boxer crabs.

Most crabs gather food with their powerful claws, but boxer crabs have adapted so thoroughly to holding anemones that their claws are now feeble, delicate tweezers rather than powerful, crushing pincers. Instead, they rely on their anemones. Some species use the anemones like cutlery, dabbing them onto morsels of food and then bringing them over to their mouths. Others wait for the anemones to passively ensnare food, which they then scrape into their mouths with their front legs. If you remove the anemones, as Yisrael Schnytzer and his colleagues from Bar Ilan University have repeatedly done, the crabs struggle to gather enough to eat.

The anemones, however, flourish apart from the crabs. When Schnytzer freed them from the crabs’ grasp, their colors got brighter, their tentacles became longer, and they more than doubled in size. Left to their own devices, they can grow far bigger than the crabs that once held them. In the words of Schnytzer’s colleague Ilan Karplus, the crabs cultivate “Bonsai anemones,” deliberately stunting their growth to keep them at a manageable size.

If you remember your high school chemistry, you'll know that helium is a bit of an oddball. This noble gas is the least reactive element on the periodic table, and thanks to its full outer shell, conventional wisdom states that helium cannot interact with other atoms to create stable compounds.

While other noble gas elements have shown signs of forming compounds under extreme pressure, helium has remained firmly exclusive - until now. Scientists report creating what appears to be a stable helium-sodium compound, and it challenges some of the most basic assumptions of modern chemistry.

"Chemistry changes when you apply high pressure, and this can be achieved inside our Earth and on different planets like Saturn," one of the team, Ivan Popov from Utah State University, told Ryan F. Mandelbaum at Gizmodo. "But this is a book changer." 

If you need a bit of a refresher on your chemistry facts, helium is the second most abundant element in the Universe, and belongs to a six-member group of elements called the noble gases - so-called because of an apparent 'aloofness' that prevents them from easily forming compounds with other elements.

Since earning their 'noble' reputation, some of these gases have shown signs of reactiveness under extreme conditions - you can actually split the noble gases up into two groups, with krypton, xenon, and radon considered to be relatively reactive, and argon, neon, and helium considered to be very unreactive.

Researchers have found ways to pair up helium with other elements in the past, but until now, the result has always been fleeting. 

One of the most common examples of helium interacting with other elements refers to van der Waals forces - attractive or repulsive forces that don't require conventional covalent or ionic bonds to form.

Being one of the most abundant elements in the Universe, responsible for forming stars and gas giant planets, helium could play by very different rules out in space and deep within our planet, and researchers have just found the first evidence yet of that weird behavior.

"Extremely high pressure, like that found at Earth's core or giant neighbours, completely alters helium's chemistry," one of the team, Alex Boldyrev from Utah State, told Mary-Ann Muffoletto at Phys.org.

The researchers used a 'crystal structure-predicting' computer model to predict that under extreme pressures, a stable helium-sodium compound could form.  They then physically created the never-before-seen compound, Na2He, in a diamond anvil cell experiment, which allowed them to subject helium and sodium atoms to pressures of around 1.1 million times Earth's atmospheric pressure.

"These findings were so unexpected, Boldyrev says, that he and colleagues struggled for more than two years to convince science reviewers and editors to publish their results," says Muffoletto.

It's small but it will rip you apart using only magnetism.

Scientists at the University of Warwick have discovered the first white dwarf pulsar we’ve ever seen. The super-dense body is housed in an exotic binary star system 380 light-years away from Earth.

Professors Tom Marsh and Boris Gänsicke of the University’s Astrophysics Group together with Dr David Buckley from the South African Astronomical Observatory, have made astronomical history — they have identified the first white dwarf pulsar humanity has ever seen, in the neighboring system of AR Scorpii (AR Sco). Astronomers have been on the lookout for this class of pulsar for over half a century now.

AR Sco is only 380 light-years away from Earth, in the Scorpius constellation. It has two stars — a very rapidly spinning former star known as a white dwarf pulsar, and an actual star known as a red dwarf — locked together in a 3.6-hour orbit.

The red dwarf isn’t very noticeable in and of itself. It weighs one-third of a Solar mass (the biggest ones reach one-half of a solar mass). It ‘burns’ helium just like our Sun but at a much slower rate. So it’s not particularly hot or very bright at all. Standard red dwarf across the board.

However, its choice of companions creates some spectacular interaction which brought the scientists’ attention to the system in the first place. Its neighboring pulsar isn’t much bigger than Earth, but it’s an estimated 200,000 times denser. Like all pulsars, it’s a kind of neutron star and very lively celestial body.

What sets it apart is the way it formed. Neutron stars are the naked cores of huge stars squashed by supernovae into pure matter — they’re one huge atomic nuclei, without any empty space for electron orbits or personal space or whatnot. It’s the closest a star can get to a black hole without turning to the dark side. The white dwarf pulsar is smaller, less dense, and formed after the outer layers of a Sun-like star breezed away into a planetary nebula.

In 2022, there will be a spectacular sky show. Two stars will merge into one, pushing out excess gas into an explosion known as a red nova. At magnitude 2, it will be as bright as Polaris in the sky, and just behind Sirius and Vega in brightness. The collision in the constellation of Cygnus will be visible for up to six months.

That’s pretty impressive. What’s more impressive: we’ve never been able to predict a nova before. But Lawrence Molnar, a professor of astronomy and physics at Calvin College, was able to find a pair of oddly behaving stars giving an indication of what might happen.

The objects, termed KIC 9832227, are currently contact binaries. Contact binary refers to two objects that are so close they are currently touching. The object was discovered by Kepler. The expected outcome is a merger between the two stars that will put on quite a show. Because both are low mass stars, the expected temperature is low, with Molnar terming it a “red nova.”

So how does Molnar know what will happen? After all, as he puts it, it’s “a very specific prediction that can be tested, and a big explosion.” He and his team have an example to look at: V1309 Scorpii. First observed in 2008, astronomers were able to watch the light curve as the event unfolded. First, there were a few “booms” in the sky. Then, a spectacular light show unfolded. Using precovery data, astronomers were able to trace back the evolution from 2001 on, giving a big picture of the decade of progression of the event.

These transient features are so named because they last about 20 milliseconds.

Scientists don't know much about the mysterious, powerful electric discharges that sometimes occur in the upper levels of the atmosphere in conjunction with thunderstorms. The first photograph of the phenomenon—which can occur as high as about 90km above the surface of the Earth and are known variously as sprites, pixies, elves, or jets—was only taken from Earth in 1989.

Fortunately for scientists interested in these storms, the International Space Station offers an excellent vantage point at an altitude of about 400km. So Danish researchers devised a "Thor experiment"—named after the hammer-wielding Norse god—to study the phenomenon. As part of the experiment, an astronaut on board the station would image thunderstorms under certain conditions, and these observations would be correlated with data collected by satellites and ground-based radar and lightning detection systems.

6% of the electricity generated in America is used to power air-conditioning systems that cool homes and offices. As countries such as Brazil, China and India grow richer, they will surely do likewise. Not only is that expensive for customers, it also raises emissions of greenhouse gases in the form both of carbon dioxide from burning power-station fuel and of the hydrofluorocarbons air conditioners use as refrigerants.

As they describe in a paper in this week’s Science, Ronggui Yang and Xiaobo Yin of the University of Colorado, in Boulder, have a possible alternative to all this. They have invented a film that can cool buildings without the use of refrigerants and, remarkably, without drawing any power to do so. Better yet, this film can be made using standard roll-to-roll manufacturing methods at a cost of around 50 cents a square meter.

The new film works by a process called radiative cooling. This takes advantage of that fact that Earth’s atmosphere allows certain wavelengths of heat-carrying infrared radiation to escape into space unimpeded. Convert unwanted heat into infrared of the correct wavelength, then, and you can dump it into the cosmos with no come back.

Dr Yang and Dr Yin are not the first to try to cool buildings in this way. Shanhui Fan and his colleagues at Stanford University, in California, demonstrated a device that used the principle in 2014. Their material, though, consisted of seven alternating layers of hafnium dioxide and silicon dioxide of varying thicknesses, laid onto a wafer made of silicon. This would be difficult and expensive to manufacture in bulk.

 Dr Yang’s and Dr Yin’s film, by contrast, was made of polymethylpentene, a commercially available, transparent plastic sold under the brand name TPX. Into this they mixed tiny glass beads. They then drew the result out into sheets about 50 millionths of a metre (microns) thick, and silvered those sheets on one side. When laid out on a roof, the silver side is underneath. Incident sunlight is thus reflected back through the plastic, which stops it heating the building below.

Preventing something warming up is not, though, the same as cooling it. The key to doing this is the glass beads. Temperature maintenance is not a static process. All objects both absorb and emit heat all the time, and the emissions are generally in the form of infrared radiation. In the case of the beads, the wavelength of this radiation is determined by their diameter. Handily, those with a diameter of about eight microns emit predominantly at wavelengths which pass straight through the infrared “window” in the atmosphere. Since the source of the heat that turns into this infrared is, in part, the building below, the effect is to cool the building.

The angular momentum of light plays an important role in many areas, from optical trapping to quantum information. In the usual three-dimensional setting, the angular momentum quantum numbers of the photon are integers, in units of the Planck constantħ. A group of scientists now show that, in reduced dimensions, photons can have a half-integer total angular momentum. They identify a new form of total angular momentum, carried by beams of light, comprising an unequal mixture of spin and orbital contributions. The scientists demonstrate the half-integer quantization of this total angular momentum using noise measurements. They conclude that for light, as is known for electrons, reduced dimensionality allows new forms of quantization.

Some moths use fruit of trees they pollinate as food for their larvae, but one East Asian moth matures within the fruit right until adulthood.

Visit a forest in south-east China, say, in mid-March and you might catch one of the more unusual sights in the natural world. The ripe fruit of one species of tree burst open at that time each year – and fully developed moths fly out. Leafflower moths have a special relationship with leafflower trees, of the genus Glochidion. The trees produce male and female flowers in April and May. Most insects overlook them by day, perhaps because they don’t produce nectar.

At night, though, the flowers release a perfume that is irresistible to leafflower moths. Females flock to the trees and perform a very specific routine. First, they visit the male flowers, where they carefully collect pollen on their proboscis. Then they head to a female flower, using the pollen to fertilize the bloom. Pollination complete, they lay one egg in the flower. A few months later, the egg hatches. By that time, the fertilized flower should have matured into a fruit, providing the larva with food – it eats two or three of the half-dozen seeds inside.

Eventually the intimate relationship with the trees ends when the larva chews its way out of the fruit, pupates on the forest floor over winter and emerges as an adult moth in the spring.

One species – E. lanceolaria – does things a little differently. It still lays its eggs in April and May, but the species of tree it chooses – G. lanceolarium – takes ages to bear fruit. In fact, it isn’t until January of the following year that the fruit begin to develop. Only at this point do the larvae emerge from their eggs and begin to feed on the fruit.

With their development squeezed into a few short months, the larvae simply metamorphose into adults while still inside the fruit. A few weeks later, in March, the fruits mature – and the moths fly out, just in time to mate and lay their eggs in the tree’s new blooms.

Three new minerals discovered by a Michigan Tech alumnus are secondary crusts found in old uranium mines. They're bright, yellow and hard to find. The mines closed four decades ago, but that doesn’t stop air and water from traveling the long tunnels of Red Canyon. The old opening at the mine—the adit—cuts straight into the hill and has helped make new minerals. The adit opens to a dry panorama in southern Utah.

"Have you ever seen The Hills Have Eyes? It's that kind of creepy, barren desert landscape," says Travis Olds '12 and now a graduate student at Notre Dame studying uranyl mineral compounds. He adds that he and others find mineralogy so exciting because of "the idea that there are things we still don't know—and someone can see a pretty crystal and appreciate it."

Olds specifically studies uranyl minerals because, as radioactive materials, it is important to know where they are found and how they change in different environments. Within the past year, he found three new uranium minerals in Red Canyon: leesite, leószilárdite and redcanyonite.

A massive chunk of ice roughly the size of Delaware is about to break away from the fourth-largest ice shelf in Antarctica. British scientists have been watching a crack steadily develop in the Larsen C ice shelf for years. But the rift has expanded dramatically in the past few weeks, and there are now only about 12 miles of ice preventing a 1,900-square-mile section from coming free. The split not only will form one of the largest icebergs in history but also will leave Larsen C vulnerable to a complete collapse, which could speed up the flow of glacial ice into the ocean and indirectly add nearly 4 inches to global sea levels. Two neighboring ice shelves, Larsen A and Larsen B, collapsed after similar breakaways. The researchers believe the rift, which is now 100 miles long and 1,000 feet wide, will reach the shoreline imminently.

Pancreatic cancer is known as the “silent killer” because it is usually too advanced by the time it is discovered. An early blood test could change that.

Tumor-derived extracellular vesicles (EVs) are of increasing interest as a resource of diagnostic biomarkers. However, most EV assays require large samples and are time-consuming, low-throughput and costly, and thus impractical for clinical use.

A group of scientists now describe a rapid, ultrasensitive and inexpensive nanoplasmon-enhanced scattering (nPES) assay that directly quantifies tumour-derived EVs from as little as 1 μl of plasma. The assay uses the binding of antibody-conjugated gold nanospheres and nanorods to EVs captured by EV-specific antibodies on a sensor chip to produce a local plasmon effect that enhances tumor-derived EV detection sensitivity and specificity. The team identified a pancreatic cancer EV biomarker, ephrin type-A receptor 2 (EphA2), and demonstrates that an nPES assay for EphA2-EVs distinguishes pancreatic cancer patients from pancreatitis patients and healthy subjects.

EphA2-EVs were also informative in staging tumor progression and in detecting early responses to neoadjuvant therapy, with better performance than a conventional enzyme-linked immunosorbent assay. The nPES assay can be easily refined for clinical use, and readily adapted for diagnosis and monitoring of other conditions with disease-specific EV biomarkers.