All posts tagged: Magnetic fields

Student astronomer discovers rare white dwarf star feeding on a red dwarf companion

Student astronomer discovers rare white dwarf star feeding on a red dwarf companion

Published by Jenni Sidey

ASKAP J1745-5051 did not look like an easy answer to anything. It flashed radio waves every 1.4 hours, then went quiet for stretches. Then it lit up again with a pattern astronomers had trouble classifying. That odd behavior has now helped pin down one of astronomy’s stranger new mysteries. In a study published in Nature Astronomy, an international team reports that ASKAP J1745-5051 is a compact binary system. In this system, a white dwarf is pulling material from a low-mass red dwarf companion. The finding offers some of the strongest evidence yet that at least some long-period radio transients come from white dwarf binaries. Previously, many had suspected they came from slowly spinning neutron stars. The system was first spotted in an untargeted search for circularly polarized radio sources with the Australian Square Kilometre Array Pathfinder, or ASKAP. Additionally, follow-up observations with MeerKAT sharpened its position. Astronomers matched it to a faint optical source in Gaia data. What they found next changed the story. Artist’s impression of the white dwarf binary ASKAP J1745-5051. The smaller, …

Time-varying magnetic fields can create exotic quantum matter

Time-varying magnetic fields can create exotic quantum matter

Published by Jenni Sidey

Quantum technology often gets pitched as a faster kind of computing. This research points in a different direction first: control. By changing a magnetic field on a schedule, rather than leaving it fixed, physicists found they could make matter settle into quantum states that do not exist in ordinary stationary materials. That is the idea behind new work from Cal Poly lecturer Ian Powell and student researcher Louis Buchalter, who examined what happens when magnetic flux on a lattice flips between different values over time. Their study, published in Physical Review B as “Flux-Switching Floquet Engineering,” looks at how time-dependent driving can reorganize quantum systems into unusual topological phases, including some with no static counterpart. “On a big-picture level, I would describe this as an advance in our understanding of how time-dependent control can create and organize new forms of quantum matter,” Powell said. “The central idea is that useful quantum properties can depend not just on what a material is, but on how it is driven in time. In our case, we show that …

New form of friction arises purely from magnetic interactions – no contact required

New form of friction arises purely from magnetic interactions – no contact required

Published by Jenni Sidey

Friction usually announces itself through contact. A chair scraping across a floor, a tire gripping asphalt, a hand sliding over fabric. For centuries, the rule seemed simple: press harder, and resistance grows. That idea, formalized in Amontons’ law, has guided physics since the 17th century. Now a tabletop experiment suggests a very different picture can emerge when nothing touches at all. Researchers at the University of Konstanz have identified a form of friction that arises purely from magnetic interactions. No surfaces rub together. No material wears down. Yet resistance appears, peaks, and then fades again as conditions change. The familiar rule linking friction to load no longer holds in a straightforward way. Instead of steadily increasing, friction rises to a maximum and then drops, all because of how tiny magnetic elements struggle to agree with each other. Experimental set-up, total friction and order parameter. (CREDIT: Nature) When More Pressure Does Not Mean More Resistance Amontons’ law rests on a simple observation. Heavier objects press surfaces together, increasing microscopic contact points and boosting friction. That logic …

Scientists are rethinking how young galaxies formed their magnetic fields

Scientists are rethinking how young galaxies formed their magnetic fields

Published by Jenni Sidey

Magnetic fields that stretch across thousands of light-years should take a very long time to organize. Standard dynamo theory puts that timeline at roughly 5 to 10 billion years in galaxies. Yet astronomers have spotted coherent magnetic fields in galactic and protogalactic environments at high redshifts, including reports up to redshift 2.6 and even 5.6. That mismatch has been a stubborn problem. A new study in Physical Review Letters argues that part of the answer may lie in the chaos of galaxy formation itself. Instead of treating magnetic growth as something that unfolds in a settled system, the researchers looked at what happens while a galaxy is still assembling from a collapsing cloud of ionized gas. “However, dynamo theory has its limitations”, says Pallavi Bhat, an assistant professor at the International Centre for Theoretical Sciences and an author of the study. “In particular, it struggles to explain observations of young galaxies with robust magnetic fields across thousands of light-years”. Collapsing plasma cloud with uniform magnetic field (red). Top Right: Compression alone amplifies the field. Bottom …

Researchers create an invisibility cloak by bending magnetic fields around real-world objects

Researchers create an invisibility cloak by bending magnetic fields around real-world objects

Published by Jenni Sidey

Magnetic invisibility sounds simple in theory. Place the right materials around an object and magnetic fields flow around it as if nothing were there. Reality has been far messier. For nearly two decades, physicists have tried to cloak objects from magnetic fields using carefully arranged materials. Early designs relied on idealized shapes such as perfect cylinders or spheres. Those forms behave predictably in equations and laboratory tests. Real devices rarely cooperate. Power cables twist through irregular housings. Electronic components form sharp corners. Industrial systems contain uneven edges and layered geometries. Once these shapes enter the picture, magnetic cloaking designs often fail, leaving obvious distortions in the surrounding field. Magnetic cloaking achieved using bilayer SC-SFM metastructures with different geometries. (CREDIT: Science Advances) Researchers at the University of Leicester now report a way around that problem. Their new framework, described in Science Advances, allows magnetic cloaks to be designed for objects with complex shapes using materials that already exist. Two Materials Working Together Magnetic cloaking typically relies on a pairing of two materials. The inner layer is …

Event Horizon Telescope captures magnetic turbulence flickering at the edge of black hole M87*

Event Horizon Telescope captures magnetic turbulence flickering at the edge of black hole M87*

Published by Jenni Sidey

For a few brief nights each year, you get a rare chance to watch a monster blink. The Event Horizon Telescope collaboration has released new, detailed views of M87*, the supermassive black hole at the heart of the galaxy M87. The images do not just show a glowing ring. They also track polarized light, a clue that reveals how magnetic fields behave near the edge of the black hole. Researchers from the University of Waterloo and the Perimeter Institute for Theoretical Physics helped construct and validate the images. What they found is both steady and startling. The size of the ring stays consistent over time. Yet the polarization pattern, the “fingerprint” of magnetism, changes sharply from year to year. That shift suggests a turbulent environment close to the event horizon. It also raises a simple question that is proving hard to answer: why did the magnetic signal fade, then flip? New images from the Event Horizon Telescope (EHT) collaboration have revealed a dynamic environment with changing polarization patterns in the magnetic fields of supermassive black …

773,000-year-old Moroccan cave fossils reveal human and neandertal evolutionary split

773,000-year-old Moroccan cave fossils reveal human and neandertal evolutionary split

Published by Jenni Sidey

A set of ancient human fossils found on Morocco’s Atlantic coast now sits on one of the tightest timelines in African prehistory. The remains come from Thomas Quarry I, and a new analysis pins them to about 773,000 years ago, give or take 4,000 years. That level of precision is rare for fossils this old, and it pulls you closer to a moment near the split that later led to modern humans, Neandertals, and Denisovans. For anyone trying to picture the human family tree, the hardest part often is timing. Fossils can be stunning, but their age can be blurry. Here, the timeline is the headline. A high-resolution magnetic record captured a major flip in Earth’s magnetic field, and the fossils sit right in that transition. ThI-GH site. (CREDIT: Nature) A Long Dig That Finally Paid Off The discoveries build on more than three decades of fieldwork under the Moroccan-French program “Préhistoire de Casablanca.” You can feel the patience behind that kind of effort. The team did long excavations, careful layer-by-layer mapping, and large geological …

Deep magma oceans generate magnetic fields to protect planets and support life

Deep magma oceans generate magnetic fields to protect planets and support life

Published by Jenni Sidey

In addition to shaping the interior of rocky planets, molten rock located deep within these planets may also contribute to the creation of a planet’s magnetic fields, which protect the entire planet from radiation. This latest discovery by scientists from the University of Rochester has shown that a basal magma ocean (a layer of molten rock) located deep within a planet may produce a long-lasting magnetic field around it. Large rocky exoplanets called super-Earths may benefit from this long-lasting magnetic field. Magnetic fields protect the atmosphere and surface of planets from charged particles as well as cosmic radiation; therefore, they play an essential role in protecting life on planets. Our planet, Earth, has a magnetic field produced by the movement of liquid iron in its outer core; however, many rocky planets, including Mars and Venus, do not have global magnetic fields at this time because the physical conditions in their cores do not support the same processes that create our magnetic field. Miki Nakajima, an associate professor in the Department of Earth and Environmental Sciences …

Superionic form of water may power planetary magnetic fields

Superionic form of water may power planetary magnetic fields

Published by Jenni Sidey

Water doesn’t behave the same way in a glass as it does as ice in your freezer. When water is heated to several thousand degrees Celsius, it is also placed under pressures many millions of times greater than the pressure of Earth’s atmosphere; the result is the special form called “superionic water”. The superionic form of water has a rigid, solid-like crystal structure composed of oxygen atoms with flowing hydrogen ions moving through that structure. As such, superionic water can conduct electricity very well. Researchers from the U.S. and various countries in Europe who work at X-ray laser facilities are now beginning to understand that the superionic form of water is actually a lot more complicated than previously thought. Their work helps to explain the unusual magnetic fields seen in other planets, such as Uranus and Neptune, that are believed to be composed of enormous reservoirs of water located deep inside those planets. The research used the Matter in Extreme Conditions (MEC) instrument from the Linac Coherent Light Source at the U.S. Department of Energy …

Astronomers spot an ‘impossible’ shock wave around a dead star system

Astronomers spot an ‘impossible’ shock wave around a dead star system

Published by Jenni Sidey

Astronomers at Durham University and collaborators at the University of Warwick used the European Southern Observatory’s Very Large Telescope to spot something that should not exist: a bright bow-shaped shock wave wrapped around a compact dead star system called RXJ0528+2838. The finding suggests this tiny stellar remnant is pushing material into space far more strongly than current models allow. “We found something never seen before and, more importantly, entirely unexpected,” says Simone Scaringi, an associate professor at Durham University and a co-lead author. “The surprise that a supposedly quiet, discless system could drive such a spectacular nebula was one of those rare ‘wow’ moments,” Scaringi says. Krystian Ilkiewicz, a postdoctoral researcher at the Nicolaus Copernicus Astronomical Center in Warsaw and a co-lead author, says the observations point to a major gap in understanding. “Our observations reveal a powerful outflow that, according to our current understanding, shouldn’t be there,” he says. Astronomers use “outflow” to describe matter ejected from an object into space. This image from the Digitized Sky Survey (DSS) shows the region of the …