Scientists Proposed, “There Might Be Massive Black Holes Than SMBH”, And They Call It SLAB’s (Astronomy)

Bernard Carr and colleagues recently considered the observational constraints on stupendously large black holes (SLABs) in the mass range M≳10¹¹ M, i.e. about the size of 100 billion suns or more. Discovering such gargantuan black holes may shed light on the nature of a significant fraction of the mysterious dark matter that makes up four-fifths of the matter in the universe.

Currently the largest known black hole, powering the quasar TON 618, has a mass of 66 billion solar masses. TON 618’s enormous bulk led scientists to speculate whether or not even larger black holes exist, and if there is any upper limit to their sizes.

In the new study, the researchers dubbed black holes 100 billion solar masses in size or larger — bigger than any currently seen — “stupendously large black holes,” or SLABs. Although they noted there is currently no evidence that stupendously large black holes are real, they noted that supermassive black holes almost that size do exist.

A key question when it comes to stupendously large black holes is whether they could form in the first place. However, much remains uncertain about how even regular supermassive black holes are born.

The conventional assumption is that the supermassive black holes at the hearts of galaxies formed as smaller black holes merged and gobbled up matter around them. However, previous research found this model faced challenges when it comes to explaining how black holes could have reached supermassive sizes when the universe was only a few billion years old.

Another way to explain how both regular supermassive black holes and possibly stupendously large black holes formed hinges on so-called primordial black holes. Prior work speculated that within a second after the Big Bang, random fluctuations of density in the hot, rapidly expanding newborn universe might have concentrated pockets of matter enough for them to collapse into black holes. These primordial black holes could have served as seeds for larger black holes to form later on.

If primordial black holes do exist, they might help explain what dark matter is. Although dark matter is thought to make up most of the matter in the universe, scientists don’t know what this strange stuff is made of, as researchers still have not seen it; it can currently be studied only through its gravitational effects on normal matter. The nature of dark matter is currently one of the greatest mysteries in science.

One way to detect stupendously large black holes is through gravitational lensing.

Another way to detect stupendously large black holes is through the effects they would have on their environment, such as gravitationally distorting galaxies. These black holes could also generate heat, light and other radiation as they consume matter that astronomers could detect.

Aside from primordial black holes, another potential candidate for dark matter are so-called weakly interacting massive particles (WIMPs). If WIMPs exist, they would be invisible and largely intangible, but previous research suggested that if two WIMPs ever collided, they would annihilate one another and generate gamma rays, providing a way for scientists to spot them indirectly. The powerful gravitational pulls of stupendously large black holes would gather a halo of WIMPs around them, and the high-energy gamma rays that could result from WIMP annihilation might help scientists discover stupendously large black holes.

They also commented on the constraints on the mass of ultra-light bosons from future measurements of the mass and spin of SLABs.

References: Bernard Carr, Florian Kuhnel, Luca Visinelli, “Constraints on Stupendously Large Black Holes”, ArXiv, 2020. Doi: arXiv:2008.08077v2 link: https://arxiv.org/abs/2008.08077

Scientists Developed New Design Principles For Spin Based Quantum Materials (Quantum)

Northwestern University materials scientists have developed new design principles that could help spur development of future quantum materials used to advance (IoT) devices and other resource-intensive technologies while limiting ecological damage.

A crystal structure (left) and a visual model of the spin helix (right). Credit: Northwestern University

The study marks an important step in Rondinelli’s efforts to create new materials that are non-volatile, energy efficient, and generate less heat—important aspects of future ultrafast, low-power electronics and quantum computers that can help meet the world’s growing demand for data.

Rather than certain classes of semiconductors using the electron’s charge in transistors to power computing, solid-state spin-based materials utilize the electron’s spin and have the potential to support low-energy memory devices. In particular, materials with a high-quality persistent spin texture (PST) can exhibit a long-lived persistent spin helix (PSH), which can be used to track or control the spin-based information in a transistor.

Although many spin-based materials already encode information using spins, that information can be corrupted as the spins propagate in the active portion of the transistor. The researchers’ novel PST protects that spin information in helix form, making it a potential platform where ultralow energy and ultrafast spin-based logic and memory devices operate.

The research team used quantum-mechanical models and computational methods to develop a framework to identify and assess the spin textures in a group of non-centrosymmetric crystalline materials. The ability to control and optimize the spin lifetimes and transport properties in these materials is vital to realizing the future of quantum microelectronic devices that operate with low energy consumption.

The limiting characteristic of spin-based computing is the difficulty in attaining both long-lived and fully controllable spins from conventional semiconductor and magnetic materials. Their study will help future theoretical and experimental efforts aimed at controlling spins in otherwise non-magnetic materials to meet future scaling and economic demands.

Rondinelli’s framework used microscopic effective models and group theory to identify three materials design criteria that would produce useful spin textures: carrier density, the number of electrons propagating through an effective magnetic field, Rashba anisotropy, the ratio between intrinsic spin-orbit coupling parameters of the materials, and momentum space occupation, the PST region active in the electronic band structure. These features were then assessed using quantum-mechanical simulations to discover high-performing PSHs in a range of oxide-based materials.

The researchers used these principles and numerical solutions to a series of differential spin-diffusion equations to assess the spin texture of each material and predict the spin lifetimes for the helix in the strong spin-orbit coupling limit. They also found they could adjust and improve the PST performance using atomic distortions at the picoscale. The group determined an optimal PST material, Sr3Hf2O7, which showed a substantially longer spin lifetime for the helix than in any previously reported material.

Their approach provides a unique chemistry-agnostic strategy to discover, identify, and assess symmetry-protected persistent spin textures in quantum materials using intrinsic and extrinsic criteria. They proposed a way to expand the number of space groups hosting a PST, which may serve as a reservoir from which to design future PST materials, and found yet another use for ferroelectric oxides—compounds with a spontaneous electrical polarization. Their work will also help guide experimental efforts aimed at implementing the materials in real device structures.

This study has been republished from Science daily.

References: Xue-Zeng Lu, James M. Rondinelli. Discovery Principles and Materials for Symmetry-Protected Persistent Spin Textures with Long Spin Lifetimes. Matter, 2020; DOI: 10.1016/j.matt.2020.08.028 link: https://www.cell.com/matter/fulltext/S2590-2385(20)30455-0?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2590238520304550%3Fshowall%3Dtrue

How The Brain’s Inner Clock Measures Seconds? (Neuroscience)

UCLA researchers have pinpointed a second hand to the brain’s internal clock. By revealing how and where the brain counts and represents seconds, the UCLA discovery will expand scientists’ understanding of normal and abnormal brain function.

Tracking the passage of time to the second is critical for motor control, learning and cognition, including the ability to anticipate future events. While the brain depends on its circadian clock to measure hours and days, the circadian clock does not have a second hand.

Instead the brain measures seconds through changing patterns of cellular activity. Much like a line of falling dominoes, each neuron activates the next, and time is marked by the neuron that is currently active. By analogy, if a sequence of falling dominoes takes 10 seconds from start to finish, one can deduce that 5 seconds has elapsed when the middle domino falls.

UCLA neuroscientists introduced mice to two different scents. The mice learned that one odor predicted the arrival of a sweet liquid reward after three seconds, while the other odor predicted a reward after six seconds. The mice started licking the spout earlier in anticipation of the reward after they sniffed the first scent than when they smelled the second.

Recordings in the striatum and premotor cortex of the brain revealed that changing patterns of neural activity in both regions encoded time—consistent with the notion that the brain has multiple clocks. But the pattern in the striatum was closer to the sequence of falling dominoes—a pattern referred to as a neural sequence—compared to the patterns in a motor area that provides input to the striatum.

Timing is a fundamental part of human behavior, learning and thought. By revealing how and where the brain counts and represents seconds, the UCLA discovery will deepen scientists’ understanding of normal and abnormal brain function.

References: Shanglin Zhou, Sotiris C. Masmanidis, Dean V. Buonomano, “Neural Sequences as an Optimal Dynamical Regime for the Readout of Time”, Neuron, 2020 DOI:https://doi.org/10.1016/j.neuron.2020.08.020 link: https://www.cell.com/neuron/fulltext/S0896-6273(20)30651-6?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0896627320306516%3Fshowall%3Dtrue#

Chimpanzees Can Suffer For Life Like Humans, If Orphaned Before Adulthood (Biology)

Humans are unusual among animals for continuing to provision and care for their offspring until adulthood. This “prolonged dependency” is considered key for the evolution of other notable human traits, such as large brains, complex societies, and extended post-reproductive lifespans. Prolonged dependency must therefore have evolved under conditions in which reproductive success is gained with parental investment and diminished with early parental loss. Catherine Crockford and colleagues tested this idea using data from wild chimpanzees, which have similarly extended immature years as humans and prolonged mother-offspring associations. They found that males who lost their mothers after weaning but before maturity began reproducing later and had lower average reproductive success.

A chimpanzee mother’s presence and support throughout the prolonged childhood years allow their offspring time to learn the skills they need to survive in adulthood. Credit: Liran Samuni, Tai Chimpanzee Project

Major theories in human evolution argue that parents continuing to provide food to their offspring until they have grown up has enabled our species to have the largest brains of any species on the planet relative to our body size. Brains are expensive tissue and grow slowly leading to long childhoods. Ongoing parental care through long childhoods allow children time to learn the skills they need to survive in adulthood. Such long childhoods are rare across animals, equaled only by other great apes, like chimpanzees.

Chimpanzees may have long childhoods, but mothers rarely directly provide them with food after ages four to five years when they are weaned. Mostly mothers let their offspring forage for themselves. So then what do chimpanzee mothers provide their sons that gives them a competitive edge over orphaned sons? We do not yet know the answer but scientists do have some ideas.

One idea is that mothers know where to find the best food and how to use tools to extract hidden and very nutritious foods, like insects, honey and nuts. Offspring gradually learn these skills through their infant and juvenile years. Researchers can speculate that one reason offspring continue to travel and feed close to their mothers every day until they are teenagers, is that watching their mothers helps them to learn. Acquiring skills which enable them to eat more nutritious foods may be why great apes can afford much bigger brains relative to their body size than other primates.

Another idea is that mothers pass on social skills. Again a bit like humans, chimpanzees live in a complex social world of alliances and competition. It might be that they learn through watching their mothers when to build alliances and when to fight.

References: Catherine Crockford, Liran Samuni, Linda Vigilant and Roman M. Wittig, “Postweaning maternal care increases male chimpanzee reproductive success”, Science Advances, 2020, Vol. 6, no. 38, eaaz5746 DOI: 10.1126/sciadv.aaz5746 link: https://advances.sciencemag.org/content/6/38/eaaz5746

Hubble Captures Spectacular Photos of Jupiter and Its Icy Moon Europa (Planetary Science)

Two new photos, taken with the NASA/ESA Hubble Space Telescope, show Jupiter with its turbulent atmosphere and giant storms. One of the images also features Europa, one of Jupiter’s Galilean moons.

This image of Jupiter was taken by the NASA/ESA Hubble Space Telescope on August 25, 2020, when the planet was 653 million km (406 million miles) from Earth. Image credit: NASA / ESA / A. Simon, NASA’s Goddard Space Flight Center / M.H. Wong, University of California, Berkeley / OPAL Team.

A bright, white, stretched-out storm moving at 560 km per hour (348 mph) appeared at Jupiter’s mid-northern latitudes on August 18, 2020.

While it’s common for storms to pop up in this region, often several at once, this particular disturbance appears to have more structure behind it than observed in previous storms. Trailing behind the plume are small, counterclockwise dark clumps also not witnessed in the past.

Hubble shows that the Great Red Spot, rolling counterclockwise in the planet’s southern hemisphere, is ploughing into the clouds ahead of it, forming a cascade of white and beige ribbons.

The huge storm system is currently an exceptionally rich red color, with its core and outermost band appearing deeper red.

It now measures about 15,800 km (9,818 miles) across, and is still shrinking, as noted in telescopic observations dating back to 1930, but its rate of shrinkage appears to have slowed.

A multiwavelength observation in ultraviolet/visible/near-infrared light of Jupiter obtained by Hubble on August 25, 2020 is giving astronomers an entirely new view of the giant planet. Hubble’s near-infrared imaging, combined with ultraviolet views, provides a unique panchromatic look that offers insights into the altitude and distribution of the planet’s haze and particles. This complements Hubble’s visible-light pictures that show the ever-changing cloud patterns. In this photo, the parts of Jupiter’s atmosphere that are at higher altitude, especially over the poles, look red as a result of atmospheric particles absorbing ultraviolet light. Conversely, the blue-hued areas represent the ultraviolet light being reflected off the planet. A new storm at upper left, which erupted on August 18, 2020, is grabbing the attention of scientists in this multiwavelength view. The ‘clumps’ trailing the white plume appear to be absorbing ultraviolet light, similar to the center of the Great Red Spot, and Red Spot Jr. directly below it. This provides the astronomers with more evidence that this storm may last longer on Jupiter than most storms. Image credit: NASA / ESA / A. Simon, NASA’s Goddard Space Flight Center / M.H. Wong, University of California, Berkeley / OPAL Team.

The astronomers are noticing that another feature has changed: Oval BA, nicknamed as Red Spot Jr., which appears just below the Great Red Spot in the new images.

For the past few years, Oval BA has been fading in color to its original shade of white after appearing red in 2006.

However, now the core of this storm appears to be darkening to a reddish hue. This could hint that Red Spot Jr. is on its way to reverting to a color more similar to that of its cousin.

The images also show that Jupiter is clearing out its higher-altitude white clouds, especially along the planet’s equator, which is enveloped in an orangish hydrocarbon smog.

In one of the two images, the icy moon Europa is visible to the left of Jupiter.

Hubble also captured a new multiwavelength observation in ultraviolet/visible/near-infrared light of Jupiter, which is giving astronomers an entirely new view of the giant planet.

The telescope’s near infrared imaging, combined with ultraviolet views, provides a unique panchromatic look that offers insights into the altitude and distribution of the planet’s haze and particles.

This complements Hubble’s visible-light picture that shows the ever-changing cloud patterns.

This article is based on press-releases provided by the National Aeronautics and Space Administration and the European Space Agency.

Scientists Find Efficient Way to Convert Carbon Dioxide into Ethylene (Chemistry)

Electrochemical CO2 reduction to value-added chemical feedstocks is of considerable interest for renewable energy storage and renewable source generation while mitigating CO2 emissions from human activity. Copper represents an effective catalyst in reducing CO2 to hydrocarbons or oxygenates, but it is often plagued by a low product selectivity and limited long-term stability. Now Choi and colleagues reported that copper nanowires with rich surface steps to catalyze a chemical reaction that reduces carbon dioxide (CO2) emissions while generating ethylene (C2H4), an important chemical used to produce plastics, solvents, cosmetics and other important products globally.

Copper represents an effective catalyst in reducing carbon dioxide to hydrocarbons or oxygenates, but it is often plagued by a low product selectivity and limited long-term stability. Choi et al report that copper nanowires with rich surface steps exhibit a remarkably high Faradaic efficiency for ethylene that can be maintained for over 200 hours. Image credit: Choi et al, doi: 10.1038/s41929-020-00504-x.

Using copper to kick start the carbon dioxide reduction into ethylene reaction has suffered two strikes against it.

First, the initial chemical reaction also produced hydrogen and methane — both undesirable in industrial production.

Second, previous attempts that resulted in ethylene production did not last long, with conversion efficiency tailing off as the system continued to run.

To overcome these two hurdles, Professor Goddard III and colleagues focused on the design of the copper nanowires with highly active steps — similar to a set of stairs arranged at atomic scale.

One intriguing finding of this collaborative study is that this step pattern across the nanowires’ surfaces remained stable under the reaction conditions, contrary to general belief that these high energy features would smooth out.

This is the key to both the system’s durability and selectivity in producing ethylene, instead of other end products.

The scientists demonstrated a carbon dioxide-to-ethylene conversion rate of greater than 70%, much more efficient than previous designs, which yielded at least 10% less under the same conditions.

The new system ran for 200 hours, with little change in conversion efficiency, a major advance for copper-based catalysts.

In addition, the comprehensive understanding of the structure-function relation illustrated a new perspective to design highly active and durable carbon dioxide reduction catalyst in action.

References: Choi, C., Kwon, S., Cheng, T. et al. Highly active and stable stepped Cu surface for enhanced electrochemical CO2 reduction to C2H4. Nat Catal (2020). https://doi.org/10.1038/s41929-020-00504-x link: https://www.nature.com/articles/s41929-020-00504-x

Astronomers Precisely Measure Distance to Magnetar (Astronomy)

XTE J1810−197 (J1810), a magnetar located in the constellation of Sagittarius, was the first magnetar identified to emit radio pulses, and has been extensively studied during a radio-bright phase in 2003–2008. It is estimated to be relatively nearby compared to other Galactic magnetars, and provides a useful prototype for the physics of high magnetic fields, magnetar velocities, and the plausible connection to extragalactic fast radio bursts. Upon the re-brightening of the magnetar at radio wavelengths in late 2018, researchers of current study resumed an astrometric campaign on J1810 with the Very Long Baseline Array, and sampled 14 new positions of J1810 over 1.3 years and has made the direct geometric measurement of the distance to XTE J1810-197, a magnetar located in the constellation of Sagittarius.

An artist’s impression of a magnetar emitting a burst of radiation. Image credit: Sophia Dagnello, NRAO / AUI / NSF.

Magnetars are a variety of neutron stars — the superdense remains of massive stars that exploded as supernovae — with extremely strong magnetic fields.

A typical magnetar magnetic field is a trillion times stronger than the Earth’s magnetic field, making magnetars the most magnetic objects in the Universe.

They can emit strong bursts of X-rays and gamma rays, and recently have become a leading candidate for the sources of fast radio bursts (FRBs).

Researchers performed the phase calibration for the new observations with two phase calibrators that are quasi-colinear on the sky with J1810, enabling substantial improvement of the resultant astrometric precision. They then, combine their new observations with two archival observations from 2006 and have refined the proper motion and reference position of the magnetar and have measured its annual geometric parallax, the first such measurement for a magnetar.

This effect, called parallax, allows astronomers to use geometry to directly calculate the object’s distance. And what they found?

They found that the parallax of 0.40 ± 0.05 mas corresponds to a most probable distance 2.5 (↑+0.4 ↓−0.3) kpc for J1810. Their new astrometric results confirm an unremarkable transverse peculiar velocity of ≈200 km s−¹ km for J1810, which is only at the average level among the pulsar population. The magnetar proper motion vector points back to the central region of a supernova remnant (SNR) at a compatible distance at ≈70 kyr ago, but a direct association is disfavored by the estimated SNR age of ∼3 kyr.

References: H Ding, A T Deller, M E Lower, C Flynn, S Chatterjee, W Brisken, N Hurley-Walker, F Camilo, J Sarkissian, V Gupta, A magnetar parallax, Monthly Notices of the Royal Astronomical Society, , staa2531, https://doi.org/10.1093/mnras/staa2531

Only 3 People Know How To Make Rarest Pasta On The Earth (Food)

Imagine yourself on a pilgrimage. Traveling by foot, you and hundreds more make a rugged journey uphill in search of a singular experience. You’re not having a religious awakening. You’re just trying to get some pasta. But not just any pasta: it’s the rarest pasta on Earth.

Sufilindeu goes back at least 200 years — possibly as far back as 300. However old the recipe is, it’s a family affair. For centuries, the secret has been passed down from mother to daughter in the remote mountain village of Lula. Today, the recipe is kept by three women: Paola Abraini, her niece, and her sister-in-law. These are the only people on the planet capable of creating the dish, which consists of impossibly thin strands arranged in an intricate, gauzy lattice. It’s that incredibly skinny, fine structure that gives the pasta its name, which translates as “threads of God.” Angel hair, eat your heart out.

To try su filindeu, you’ll have to do a couple of things. First, you’ll have to wait until one of the biannual Feasts of San Francesco, in May and October. Those are the only times that the women make their pasta available to the public. Next, you’ll have to travel to the island of Sardinia, and then head towards the mountainous inland. The final part of your journey you need to complete on foot. It’s a 20-mile (32-kilometer) trek uphill with a couple hundred fellow travelers. At the end of it, you’ll be rewarded with a footbath and a bowl of rich but delicate su filindeu.

Actually, we might be exaggerating the secrecy of the secret. It’s not necessarily that the masters of su filindeu refuse to share the recipe. It’s probably more accurate to say that other would-be pasta-makers just can’t master it. In 2016, celebrity chef Jamie Oliver attempted to learn the technique but gave up after two hours. Abraini was willing to try to teach him, but he was in for an uphill battle because he didn’t grow up learning how to make the pasta. As Abraini told the BBC, “Many people say that I have a secret I don’t want to reveal. But the secret is right in front of you. It’s in my hands.”

The World’s Rarest Pasta Is Made Entirely by Hand

The Brazil Nut Effect Is The Mysterious Reason Big Nuts End Up On Top (Science)

Everyone knows what “mixed nuts” really means: a decidedly un-mixed tin with a layer of small peanuts and cashews on the bottom and massive walnuts and Brazil nuts on top. This spontaneous snack sorting is due to the peculiarities of fluid dynamics, and it has a name: the Brazil nut effect.

Despite the nut-centric title, any container full of particles of different sizes can fall prey to this effect when jostled enough (which is why shaking the box won’t help!). Think granola, where the first bowl you pour gets all the delicious clusters and the last bowl gets nothing but oat dust, or coffee grounds, which look perfectly even when they go into the coffee maker but have big partially ground beans at the top when they come out. This everyday phenomenon is deceptively complex, with multiple mechanisms at work. One is percolation. When all of the particles in a container are tossed up together and come back down, small particles move into the spaces beneath larger ones, thereby pushing them upward. Another mechanism is convection: the way particles in the center of a shaken pile will push upward until they get to the top, then fall down in the spaces created at the sides of a container, repeating in a swirling path.

The Brazil nut effect happens when a large particle reaches the top, then just hangs out there. Scientists aren’t sure why this occurs. One reason could be that the particles are too big to fit in the available spaces on the sides of the container. Sometimes, it’s because that particle is a different density than the particles around it—scientists have found that when a particle is either much more or much less dense than its fellow particles, it moves toward the surface much faster. Here’s where things get mysterious: that doesn’t happen when the container is placed in a vacuum chamber, suggesting that the pressure of the air between the particles has something to do with it. Scientists are still studying this phenomenon to learn more about how particles move. And you thought it was just a tin of mixed nuts! Dig deeper into this nutty phenomenon, and other scientific priniciples on display in your food, below.

THE BRAZIL NUT EFFECT