Wednesday, 19 February 2025

 

James Webb Space Telescope reveals ongoing, rapid-fire light show

Date:
February 18, 2025
Source:
Northwestern University
Summary:
Astrophysicists have observed our central supermassive black hole. They found the accretion disk is constantly emitting flares without periods of rest. Shorter, faint flares and longer, bright flares appear to be generated by separate processes.

The supermassive black hole at the center of the Milky Way appears to be having a party -- and it is weird, wild and wonderful.



Using NASA's James Webb Space Telescope (JWST), a Northwestern University-led team of astrophysicists has gained the longest, most detailed glimpse yet of the void that lurks in middle of our galaxy.

The swirling disk of gas and dust (or accretion disk) orbiting the central supermassive black hole, called Sagittarius A*, is emitting a constant stream of flares with no periods of rest, the researchers found. While some flares are faint flickers, lasting mere seconds, other flares are blindingly bright eruptions, which spew daily. There also are even fainter flickers that surge for months at a time. The level of activity occurs over a wide range of time -- from short interludes to long stretches.

The new findings could help physicists better understand the fundamental nature of black holes, how they interact with their surrounding environments and the dynamics and evolution of our own galactic home.

The study will be published on Tuesday (Feb. 18) in The Astrophysical Journal Letters.

"Flares are expected to happen in essentially all supermassive black holes, but our black hole is unique," said Northwestern's Farhad Yusef-Zadeh, who led the study. "It is always bubbling with activity and never seems to reach a steady state. We observed the black hole multiple times throughout 2023 and 2024, and we noticed changes in every observation. We saw something different each time, which is really remarkable. Nothing ever stayed the same."

An expert on the Milky Way's center, Yusef-Zadeh is a professor of physics and astronomy at Northwestern's Weinberg College of Arts and Sciences. The international team of coauthors includes Howard Bushouse of the Space Telescope Science Institute, Richard G. Arendt of NASA, Mark Wardle of Macquarie University in Australia, Joseph Michail of Harvard & Smithsonian and Claire Chandler of the National Radio Astronomy Observatory.

Random fireworks

To conduct the study, Yusef-Zadeh and his team used the JWST's near infrared camera (NIRCam), which can simultaneously observe two infrared colors for long stretches of time. With the imaging tool, the researchers observed Sagittarius A* for a total of 48 hours -- in 8-to-10-hour increments across one year. This enabled scientists to track how the black hole changed over time.

While Yusef-Zadeh expected to see flares, Sagittarius A* was more active than he anticipated. Simply put: the observations revealed ongoing fireworks of various brightness and durations. The accretion disk surrounding the black hole generated five to six big flares per day and several small sub-flares in between.

"In our data, we saw constantly changing, bubbling brightness," Yusef-Zadeh said. "And then boom! A big burst of brightness suddenly popped up. Then, it calmed down again. We couldn't find a pattern in this activity. It appears to be random. The activity profile of the black hole was new and exciting every time that we looked at it."



Two separate processes at play

Although astrophysicists do not yet fully understand the processes at play, Yusef-Zadeh suspects two separate processes are responsible for the short bursts and longer flares. If the accretion disk is a river, then the short, faint flickers are like small ripples that fluctuate randomly on the river's surface. The longer, brighter flares, however, are more like tidal waves, caused by more significant events.

Yusef-Zadeh posits that minor disturbances within the accretion disk likely generate the faint flickers. Specifically, turbulent fluctuations within the disk can compress plasma (a hot, electrically charged gas) to cause a temporary burst of radiation. Yusef-Zadeh likens the event to a solar flare.

"It's similar to how the sun's magnetic field gathers together, compresses and then erupts a solar flare," he explained. "Of course, the processes are more dramatic because the environment around a black hole is much more energetic and much more extreme. But the sun's surface also bubbles with activity."

Yusef-Zadeh attributes the big, bright flares to magnetic reconnection events -- a process where two magnetic fields collide, releasing energy in the form of accelerated particles. Traveling at velocities near the speed of light, these particles emit bright bursts of radiation.

"A magnetic reconnection event is like a spark of static electricity, which, in a sense, also is an 'electric reconnection,'" Yusef-Zadeh said.

Double vision

Because the JWST's NIRCam can observe two separate wavelengths (2.1 and 4.8 microns) at the same time, Yusef-Zadeh and his collaborators were able to compare how the flares' brightness changed with each wavelength. Yusef-Zadeh said capturing light at two wavelengths is like "seeing in color instead of black and white." By observing Sagittarius A* at multiple wavelengths, he captured a more complete and nuanced picture of its behavior.

Yet again, the researchers were met with a surprise. Unexpectedly, they discovered events observed at the shorter wavelength changed brightness slightly before the longer-wavelength events.

"This is the first time we have seen a time delay in measurements at these wavelengths," Yusef-Zadeh said. "We observed these wavelengths simultaneously with NIRCam and noticed the longer wavelength lags behind the shorter one by a very small amount -- maybe a few seconds to 40 seconds."

This time delay provided more clues about the physical processes occurring around the black hole. One explanation is that the particles lose energy over the course of the flare -- losing energy quicker at shorter wavelengths than at longer wavelengths. Such changes are expected for particles spiraling around magnetic field lines.

Aiming for an uninterrupted look

To further explore these questions, Yusef-Zadeh hopes to use the JWST to observe Sagittarius A* for a longer period of time. He recently submitted a proposal to observe the black hole for an uninterrupted 24 hours. The longer observation run will help reduce noise, enabling the researchers to see even finer details.

"When you are looking at such weak flaring events, you have to compete with noise," Yusef-Zadeh said. "If we can observe for 24 hours, then we can reduce the noise to see features that we were unable to see before. That would be amazing. We also can see if these flares show periodicity (or repeat themselves) or if they are truly random."

The study, "Non-stop variability of Sgr A* using JWST at 2.1 and 4.8 micron wavelengths: Evidence for distinct populations of faint and bright variable emission," was supported by NASA and the National Science Foundation.


Story Source:

Materials provided by Northwestern University.


Visit Us : bookofaward.com

Contact Us :  contact@bookofaward.com


Social Media:


Tags:
- No comments:

Tuesday, 18 February 2025

Solar-powered device captures carbon dioxide from air to make sustainable fuel

 

Date:
February 13, 2025
Source:
University of Cambridge
Summary:
Researchers have developed a reactor that pulls carbon dioxide directly from the air and converts it into sustainable fuel, using sunlight as the power source.

Researchers have developed a reactor that pulls carbon dioxide directly from the air and converts it into sustainable fuel, using sunlight as the power source.



The researchers, from the University of Cambridge, say their solar-powered reactor could be used to make fuel to power cars and planes, or the many chemicals and pharmaceuticals products we rely on. It could also be used to generate fuel in remote or off-grid locations.

Unlike most carbon capture technologies, the reactor developed by the Cambridge researchers does not require fossil-fuel-based power, or the transport and storage of carbon dioxide, but instead converts atmospheric CO2 into something useful using sunlight. The results are reported in the journal Nature Energy.

Carbon Capture and Storage (CCS) has been touted as a possible solution to the climate crisis, and has recently received £22bn in funding from the UK government. However, CCS is energy-intensive and there are concerns about the long-term safety of storing pressurised CO2 deep underground, although safety studies are currently being carried out.

"Aside from the expense and the energy intensity, CCS provides an excuse to carry on burning fossil fuels, which is what caused the climate crisis in the first place," said Professor Erwin Reisner, who led the research. "CCS is also a non-circular process, since the pressurised CO2 is, at best, stored underground indefinitely, where it's of no use to anyone."

"What if instead of pumping the carbon dioxide underground, we made something useful from it?" said first author Dr Sayan Kar from Cambridge's Yusuf Hamied Department of Chemistry. "CO2 is a harmful greenhouse gas, but it can also be turned into useful chemicals without contributing to global warming."

The focus of Reisner's research group is the development of devices that convert waste, water and air into practical fuels and chemicals. These devices take their inspiration from photosynthesis: the process by which plants convert sunlight into food. The devices don't use any outside power: no cables, no batteries -- all they need is the power of the sun.

The team's newest system takes CO2 directly from the air and converts it into syngas: a key intermediate in the production of many chemicals and pharmaceuticals. The researchers say their approach, which does not require any transportation or storage, is much easier to scale up than earlier solar-powered devices.

The device, a solar-powered flow reactor, uses specialised filters to grab CO2 from the air at night, like how a sponge soaks up water. When the sun comes out, the sunlight heats up the captured CO2, absorbing infrared radiation and a semiconductor powder absorbs the ultraviolet radiation to start a chemical reaction that converts the captured CO2 into solar syngas. A mirror on the reactor concentrates the sunlight, making the process more efficient.

The researchers are currently working on converting the solar syngas into liquid fuels, which could be used to power cars, planes and more -- without adding more CO2 to the atmosphere.

"If we made these devices at scale, they could solve two problems at once: removing CO2 from the atmosphere and creating a clean alternative to fossil fuels," said Kar. "CO2 is seen as a harmful waste product, but it is also an opportunity."

The researchers say that a particularly promising opportunity is in the chemical and pharmaceutical sector, where syngas can be converted into many of the products we rely on every day, without contributing to climate change. They are building a larger scale version of the reactor and hope to begin tests in the spring.

If scaled up, the researchers say their reactor could be used in a decentralised way, so that individuals could theoretically generate their own fuel, which would be useful in remote or off-grid locations.

"Instead of continuing to dig up and burn fossil fuels to produce the products we have come to rely on, we can get all the CO2 we need directly from the air and reuse it," said Reisner. "We can build a circular, sustainable economy -- if we have the political will to do it."

The technology is being commercialised with the support of Cambridge Enterprise, the University's commercialisation arm. The research was supported in part by UK Research and Innovation (UKRI), the European Research Council, the Royal Academy of Engineering, and the Cambridge Trust. Erwin Reisner is a Fellow of St John's College, Cambridge.


Story Source:

Materials provided by University of Cambridge. 


Visit Us : bookofaward.com

Contact Us :  contact@bookofaward.com


Social Media:

Tags:
- No comments:

Monday, 17 February 2025

Researchers identify a brain circuit for creativity

 

Date:
February 13, 2025
Source:
Brigham and Women's Hospital
Summary:
Researchers analyzed data from 857 patients across 36 fMRI brain imaging studies and mapped a common brain circuit for creativity.

A new study led by researchers at Mass General Brigham suggests that different brain regions activated by creative tasks are part of one common brain circuit. By evaluating data from 857 participants across 36 fMRI studies, researchers identified a brain circuit for creativity and found people with brain injuries or neurodegenerative diseases that affect this circuit may have increased creativity. Their results are published in JAMA Network Open.


"We wanted to answer the questions, 'What brain regions are key for human creativity and how does this relate to the effects of brain injuries?'" said co-senior author Isaiah Kletenik, MD, a neurologist in the Center for Brain Circuit Therapeutics at Brigham and Women's Hospital, a founding member of the Mass General Brigham healthcare system.

The study was led by Julian Kutsche, MA, first author on the paper, who completed a research fellowship at the Center for Brain Circuit Therapeutics, and in collaboration with researchers at the Center for Brain Circuit Therapeutics, Boston Children's Hospital, University College London, University of Georgia, Max Planck Institute for Human Cognitive and Brain Sciences and Charité Berlin.

"We found that many complex human behaviors such as creativity don't map to a specific brain region but do map to specific brain circuits," said co-senior author Michael D. Fox, MD, PhD, who founded and leads the Center for Brain Circuit Therapeutics, and helped develop the techniques of coordinate and lesion network mapping employed in this work.

The team first looked at fMRI data to identify brain regions activated by different creative activities such as drawing, creative writing and making music. They then assessed data from patients who had changes in creativity due to brain injury and neurodegenerative diseases.

"Some people with neurologic diseases experience a new onset of creative behavior and show specific patterns of damage that align with our creativity circuit," Kutsche said.

Kutsche said the most interesting finding to him is that different brain regions activated by creative tasks were all negatively connected to the right frontal pole. This part of your brain, Kutsche says, is important for monitoring and rule-based behaviors.

Kletenik said reduced activity in the right frontal pole could align with the hypothesis that creativity requires shutting down a function. For example, creativity may depend on inhibiting self-censoring assessments that could then allow free association and idea generation to flow more freely. "To be creative you may have to turn off your inner critic to allow yourself to find new directions and even make mistakes."

"These findings could help explain how some neurodegenerative diseases might lead to decreases in creativity while others may show a paradoxical increase in creativity," Kletenik said. "It could also potentially add a pathway for brain stimulation to increase human creativity."

Kletenik said it is important to note that these findings do not represent the entire neural circuitry involved in creativity, adding that many different parts of the brain are involved in completing different creative tasks.

"We are learning more about neurodiversity and how brain changes that are considered pathological may improve function in some ways," he said. "These findings help us better understand how the circuitry of our brains may influence and unleash creativity."


Story Source:

Materials provided by Brigham and Women's Hospital


Visit Us : bookofaward.com

Contact Us :  contact@bookofaward.com


Social Media:



Tags:



.

- No comments:

Saturday, 15 February 2025

Astronomers Unveil 'Quipu': The Universe’s Single Largest Known Structure

 

A Colossal Cosmic Revelation

Astronomers have stumbled upon a colossal cosmic structure unlike anything seen before. Spanning 1.3 billion light-years, this mysterious formation dwarfs anything previously discovered. Its intricate web of galaxies holds unimaginable mass, bending space-time itself. The true scale of this cosmic giant is only beginning to be understood.

Astronomers have identified an unprecedented cosmic titan—a vast superstructure of galaxies stretching 1.3 billion light-years across, making it the single largest known structure in the universe. Named Quipu, after the Incan system of knotted cords used for counting, this colossal filamentary web contains an unimaginable 200 quadrillion solar masses and extends more than 13,000 times the length of the Milky Way.



What Is Quipu? A Cosmic Giant Hiding in Plain Sight

Quipu is not just a supercluster—it is a superstructure of galaxy clusters and filaments that form an interconnected network spanning over a billion light-years. Unlike traditional galaxy clusters, which are tightly bound by gravity, Quipu consists of a long, central filament with multiple branching filaments, much like a woven cord.

This immense structure was not discovered through traditional detection algorithms but was visibly apparent in sky maps of galaxy clusters in a specific redshift range. The research team noted that Quipu stood out immediately, indicating its extraordinary prominence in the cosmos.



The New Hierarchy of Cosmic Giants

Before this discovery, the largest known cosmic formations included:

  • Laniākea Supercluster – The vast region of galaxies that includes our own Milky Way, stretching 500 million light-years across.

  • Shapley Supercluster – One of the densest and most massive superclusters, previously considered the largest known structure.

  • The Hercules-Corona Borealis Great Wall – A massive concentration of galaxies 10 billion light-years away, spanning up to 10 billion light-years, though its existence remains debated.

However, Quipu and four newly discovered structures outsize the Shapley Supercluster, reshaping our understanding of the universe’s large-scale distribution of matter.

These five newly classified superstructures include:

  • Quipu (red) – The largest filamentary structure ever detected.

  • Serpens-Corona Borealis superstructure (green) – Another massive formation stretching through these constellations.

  • Hercules supercluster (purple) – A dense galactic region with significant gravitational influence.

  • Sculptor-Pegasus superstructure (beige) – A massive structure connecting these two well-known constellations.

  • Shapley Supercluster (blue) – Once the reigning cosmic giant, now overshadowed by Quipu and its counterparts.

Together, these formations contain 45% of all known galaxy clusters, 30% of the observable galaxies, and 25% of all matter in the known universe. They account for 13% of the observable universe’s volume, making them some of the most influential structures in cosmic evolution.

How Quipu Was Discovered: Mapping the Cosmic Web

Astronomers detected Quipu through an advanced redshift mapping survey, focused on galaxy clusters between redshifts of 0.3 and 0.6. The greater the redshift, the farther away (and older) the structures. Most previous large-scale surveys had mapped only objects up to redshift 0.3, missing deeper, larger structures.

By extending the search range, scientists found Quipu and its counterparts—indicating that even larger structures may exist further in the universe’s past.



The Redshift Technique: A Window Into the Deep Universe

Redshift occurs because the expanding universe stretches the wavelength of light, shifting it toward the red end of the spectrum. By measuring these shifts, astronomers can estimate the distance and velocity of galaxies, helping them construct a 3D map of the universe.



A Fleeting Giant in the Grand Timeline

Despite its immense size, Quipu is not eternal. The universe is constantly expanding, and over billions of years, these vast filaments will disperse. Gravity keeps them bound for now, but as dark energy accelerates cosmic expansion, the filaments will slowly unravel, separating galaxies from one another.

The Fate of Quipu and the Cosmic Web

  • Over the next billions of years, Quipu will break into smaller clusters as cosmic expansion stretches space itself.

  • Galaxies within Quipu will drift apart, eventually becoming isolated island universes.

  • Future astronomers (if any exist) may no longer detect these superstructures, as the cosmic web itself dissolves.



What’s Next? The Hunt for Even Larger Structures

While Quipu currently holds the record as the largest known structure, astronomers believe even bigger formations may lurk deeper in space. With the continued advancement of telescope technology (such as the James Webb Space Telescope and upcoming Euclid mission), future surveys could extend redshift mapping beyond 1.0, potentially revealing structures hundreds of billions of light-years across.

This discovery, detailed in a recent study on arXiv, challenges our understanding of large-scale cosmic formations and raises fundamental questions about the structure and evolution of the universe. For now, Quipu stands as a breathtaking reminder of the sheer scale and complexity of the universe—a vast, interconnected web stretching across billions of light-years, whispering secrets from the cosmic past.


Visit Us : bookofaward.com


Contact Us :  contact@bookofaward.com


Social Media:



Tags:



- No comments:

Friday, 14 February 2025

Scientists herald active matter breakthrough with creation of three-dimensional 'synthetic worms'

 

Date:
February 13, 2025
Source:
University of Bristol
Summary:
Researchers have made a breakthrough in the development of 'life-like' synthetic materials which are able to move by themselves like worms. Scientists have been investigating a new class of materials called 'active matter', which could be used for various applications from drug delivery to self-healing materials.

Researchers at the University of Bristol have made a breakthrough in the development of "life-like" synthetic materials which are able to move by themselves like worms.



Scientists have been investigating a new class of materials called 'active matter', which could be used for various applications from drug delivery to self-healing materials.

Compared to inanimate matter -- the sort of motionless materials we come across in our lives every day such as plastic and wood -- active matter can show fascinating life-like behaviour.

These materials are made of elements which are driven out of equilibrium by internal energy sources, allowing them to move independently.

Researchers from the University of Bristol, in collaboration with scientists in Paris and Leiden, carried out the experiment using special micron-sized (one millionth of a meter) particles called Janus colloids, which were suspended in a liquid mixture.

The team then made the material active by applying a strong electric field and observed the effects using a special kind of microscope which takes three-dimensional images.

Previous research in this field had used larger colloid particles -- but by scaling the colloids to a third of their size the University of Bristol researchers were able to experiment in three-dimensions and found fascinating results.

When the electric field was turned on, the scattered colloid particles would merge together to form worm-like structures -- which creates a fully three-dimensional synthetic active matter system.

The research paper, 'Traveling Strings of Active Dipolar Colloids' has been published in Physical Review Letters. First author Mr Xichen Chao explained: "We found the formation of fascinating new structures -- self-driven active filaments that are reminiscent of living worms. We were then able to develop a theoretical framework which enabled us to predict and control the motion of the synthetic worms solely based on their lengths."

Co-author Prof Tannie Liverpool added: "While applications in the real world are probably far in the future, because these materials can move independently it could eventually lead to the ability to design devices that independently move different parts of themselves, or the design of swarms of particles which can search for a target which could have health applications by having specifically targeted medicines and treatments."

The synthetic worm chains discovered emerge under low-density conditions.

At higher densities, the researchers found the particles formed sheet-like and maze-like structures.

The University of Bristol academics believe there may be several useful applications for the breakthrough, which they are investigating now with more experiments and theoretical modelling.


Story Source:

Materials provided by University of Bristol.


Visit Us : bookofaward.com

Contact Us :  contact@bookofaward.com


Social Media:

Tags:



- No comments:

Thursday, 13 February 2025

First detection of an ultra-high-energy neutrino

 

- No comments:
Subscribe to: Posts (Atom)

  James Webb Space Telescope reveals ongoing, rapid-fire light show Date: February 18, 2025 Source: Northwestern University Summary: Astroph...