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The theory goes that black holes accrete material, often from nearby stars. However the theory also suggests there is a limit to how big a black hole can grow due to accretion and certainly shouldn’t be as large as they are seen to be in the early Universe. Black holes it seems, are fighting back and don’t care about those limits! A recent study shows that supermassive black holes are growing at rates that defy the limits of current theory. Astronomers just need to figure out how they’re doing it! 

Black holes usually form from the collapse of a massive star. The origin of their larger cousins, the supermassive black holes found at the centre of most galaxies, remains a mystery. Theories suggest they grew over billions of years by consuming stars, gas and maybe even other black holes. Others suggest they formed from the primordial conditions of the early Universe or maybe from dense clusters of hot young early stars. The immense gravity from them plays a significant part in shaping stellar formation and the evolution of their host galaxy. If a supermassive black hole is actively accreting material, they are often seen as quasars, extremely luminous objects that are visible across million, even billions of light years. 

Illustration of a powerful black hole and its magnetic field. Credit: L. Calçada/ESO

A recent discovery by a team of astronomers revealed a low-mass supermassive black hole that was devouring material at an extreme rate. The black hole is at a distance that means we are seeing light as it was 1.5 billion years after the Big Bang. This means we can learn about the processes that govern these objects when the Universe was a lot younger. 

The black hole known as LID-568 was detected by a team of astronomers led by the International Gemini Observatory/NSF NOIRLab astronomer Hyewon Suh. It was detected in images from the James Webb Space Telescope following on from assessment of galaxies from the Chandra X-ray Observatory’s COSMOS legacy survey. The galaxies observed are bright X-ray sources but not visible in optical or near-infrared surveys. The team used JWST’s NIRSpec instrument that is capable of getting a spectrum off each individual pixel in its field of view. 

The Gemini North telescope on the summit of Mauna Kea (Gemini Observatory/AURA)

The study allowed the team to make the rather unexpected discovery of immense flows of gas out from the region around the centre of the black hole.  Suh and team could infer from this that a significant fraction of the growth of LID-568  may well have occurred in one single rapid accretion event. They calculated that it must be feeding on matter at a rate which is 40 times the Eddington limit. The limit relates to the maximum luminosity it can achieve acknowledging there is a balance between the outward force of radiation and the inward force of gravity. When the two forces balance, it is known as hydrostatic equilibrium. If an object exceeds the limit then an immense outward force will result in it losing mass. When the luminosity of LID-568 was calculated it was much higher then should be theoretically possible. 

The discovery provides an excellent opportunity for astronomers to study black holes in the early Universe and in particular those that challenge the Eddington limit theory. It would however suggest that the outflows of energy are acting to release energy that has built up during extreme accretion periods. Follow up observations are required. 

Source : NSF NOIRLab Astronomers Discover the Fastest-Feeding Black Hole in the Early Universe

The post Early Black Holes Fed 40x Faster than Should Be Possible appeared first on Universe Today.

Eventually, every stellar civilization will have to migrate to a different star. The habitable zone around all stars changes as they age. If long-lived technological civilizations are even plausible in our Universe, migration will be necessary, eventually.

Could Extraterrestrial Intelligences (ETIs) use stars themselves as stellar engines in their migrations?

In broad terms, a stellar engine uses a star to generate work. A simple example is solar panels, which use the Sun’s radiation to generate electricity that we use to perform work. But the scaled-up idea is to use the star to produce thrust. That thrust could be used to move the star itself. An ETI capable of doing that would be a Type II civilization on the Kardashev Scale.

To most of us, it seems like a wildly improbable idea. But who knows what’s out there? If an ETI can survive long enough, it may become a Type II civ.

The stellar engine idea dates back to science fiction author Olaf Stapledon. A couple of decades after Stapledon, astronomer Fritz Zwicky also discussed manipulating stars with advanced technology, even turning them into spacecraft. In the decades since, the idea has persisted, and other researchers have delved into it. In 1988, Leonid Shakdov developed the first detailed stellar engine model called the Shakdov Thruster.

In new research, Clement Vidal, from Vrije Universiteit in Brussels, Belgium, examines how an advanced civilization could use a binary star as a stellar engine. The paper is titled “The Spider Stellar Engine: a Fully Steerable Extraterrestrial Design?”

“Since about half the stars in our galaxy are in binary systems where life might develop too, we introduce a model of a binary stellar engine,” Vidal writes. “We apply the model to candidate systems, spider pulsars, which are binary stars composed of one millisecond pulsar and a very low-mass companion star that is heavily irradiated by the pulsar wind.”

Vidal is concerned with stellar engine technosignatures. Research has focused on hypervelocity stars as potential stellar engine technosignatures because they’re easily observable. Other researchers have also proposed other stellar engine concepts, but according to Vidal, they’re “poorly linked to observable technosignatures. ”

Vidal’s main goal in this work is to determine what types of technosignatures a binary stellar engine would emit. He discusses what potential signatures might be emitted by acceleration, deceleration, steering, and maneuvers such as gravitational assists or captures. However, unlike some other researchers, he focuses on a specific type of binary system: spider pulsars, which are a subclass of binary millisecond pulsars.

Pulsars are what remains of some massive stars. At the end of their lives, some massive stars collapse to form neutron stars. When these neutron stars spin rapidly, they produce beams of radiation from their poles. If the radiation is aimed at Earth, then we can observe the pulses of energy. These pulses have exquisitely precise timing, and astronomers use them to determine cosmic distances.

A spider pulsar is a pulsar with a companion, usually a red dwarf, a brown dwarf, or even a planetary-mass object. They’re called spider pulsars because it’s as if the pulsar spins a web of powerful beams of radiation that strips away the companion’s mass, eventually destroying it.

Artist’s impression of a so-called “Black Widow” pulsar PSR B1957+20 (seen in the background) through the cloud of gas enveloping its brown dwarf star companion. Credit: Dr. Mark A. Garlick; Dunlap Institute for Astronomy & Astrophysics, University of Toronto

Vidal’s paper describes the payload as a pulsar with about 1.8 solar masses and the propellant as its low-mass companion star with between 0.01 and 0.7 solar masses.

In essence, the gravitationally bound binary system is the vehicle, and the smaller companion star is the propellant. The spider pulsar generates thrust by expelling propellant out of the gravitational system, and the propellant is the matter stripped from the companion.

The binary pair orbits a common center of gravity. The idea behind this binary stellar engine (BSE) is that as they orbit, the pulsar’s radiation strikes the companion or propellant star. A close binary is more effective because the closer the pulsar is to the propellant, the more thrust is generated. The assumption is that a Type II civilization would have the technology to moderate this thrust to serve their purposes by timing the radiation and heating the outer layers of the propellant star with X-ray or gamma radiation.

To decelerate, the BSE would produce active thrust in the opposite direction of travel. It could also use a passive magnetic sail deployed from the pulsar to transfer momentum to the interstellar medium.

The BSE steers by selectively evaporating the star during different orbital phases. “To choose a direction, it suffices to evaporate the companion star once per orbit, at a specific orbital phase, in order to create consistent thrust in one direction,” Vidal explains.

The top panels show the BSE in different configurations, with the top being the direction of travel. (a) The BSE is in acceleration mode. (b) the BSE is steering to the left. (c) the BSE is decelerating. (d) is a side view that shows changes in the orbital plane by asymmetric heating of the companion, which creates a lifting
force in relation to the orbital plane. The binary separation is not to scale. Image Credit: Vidal et al. 2024.

These various maneuvers and manipulations with the BSE would emit technosignatures. Have astronomers observed any candidate BSEs in the Milky Way? Possibly.

“Could our galaxy host a kind of fully steerable binary stellar engine that we proposed? This is a plausible hypothesis in the context of the stellivore hypothesis, which reinterprets some observed accreting binary stars as advanced civilizations feeding on stars,” Vidal writes.

A stellivore is a hypothesized type of civilization first proposed by Vidal that has the technology to consume its home star via accretion. They use the star’s energy to sustain their existence. Vidal writes that rather than consume the energy, they could use it to migrate to a more favourable location in the galaxy.

“For most of its time, a stellivore civilization would eat its home star via accretion. However, energy is never eternal, and instead of eating its star until the end and dying, a stellivore civilization would use its low-mass companion star as fuel not to be accreted but to be evaporated in order to create thrust and travel towards a nearby star,” Vidal explains.

This brings us to spider pulsars. Rather than accreting material, a spider pulsar appears to be evaporating its propellant companion.

There are two types of spider pulsars: Black Widows and Redblacks. The distinction is in the mass of the companion. In a black widow (BW), the companion is less than 0.1 stellar masses. In a redblack, the companion is between 0.1 and 0.7 stellar masses. Spider pulsars are different from other pulsar binaries because they evaporate their companions rather than accrete them. When pulsars accrete too much material, they can form black holes. Spider pulsars don’t tempt the same fate. Vidal calls these spider stellar engines (SSEs) rather than binary stellar engines (BSEs).

The panels in this figure show PSR J1959+2048, the original Black Widow pulsar. Left: the BW pulsar (in blue) is plotted in the RA-DEC plane, and its proper motion vector is displayed until it reaches a close encounter with a target star, in orange. Middle: a Chandra X-ray view of the BW pulsar, displaying a comet-like tail; the candidate target star is also visible in the bottom right (visualization with ESASky). Right: The composite image on the right shows the X-ray tail (in red/white) and a bow shock visible in the optical (green). Credit: X-ray: NASA/CXC/ASTRON/B. Stappers et al.; Optical: AAO/J.Bland-Hawthorn & H. Jones.

Previous researchers have studied the original BW, and Vidal writes, “… the 3D motion of the system appears to be nearly aligned with the spin axis of the MSP.” This fits in with the SSE interpretation because this perfect alignment is necessary to produce maximum thrust. A stellivore civilization would have a destination in mind, and Vidal says that he’s found a potential destination for the original Black Widow pulsar. He says that the pulsar will reach this target star in about 420 years while also acknowledging the uncertainty in this determination.

PSR J1959+2048, the original BW, also modulates itself, which could be interpreted as steering. However, it also displays other characteristics and moderation that call into question the ‘steering’ interpretation.

Ultimately, Vidal’s SSE may have a shorter duty cycle than other proposed stellar engines, limiting its usefulness. However, it has advantages in steering over others. “Transposing it on a smaller scale, it might also be an inspirational design for advanced propulsion solutions, or for planetary defence purposes such
as deflecting asteroids,” Vidal writes.

The idea may seem preposterous to some, but that’s incidental. Many ideas in history seemed preposterous until they weren’t.

Vidal isn’t claiming that we’re seeing the technosignatures of stellar engines. He’s arguing that it’s worth pursuing the idea of observing them. He sees these candidates and predictions of what their signals might look like as clues and as starting points for further investigation.

“Spider pulsars thus offer observable stellar engine technosignature candidates, with decades of data, active studies that discover, model and monitor these dazzling systems,” he concludes.

The post A Spider Stellar Engine Could Move Binary Stars Halfway Across a Galaxy appeared first on Universe Today.

Samantha Harvey has won the UK's top fiction prize for a novel that takes place over 24 hours on the International Space Station

AI and Google Street View have created 'digital twins' of living trees in North American cities – part of a huge simulation that could help make urban tree planting and trimming decisions

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In 2023, 107,543 Americans died from an overdose—over 75 thousand of those overdosed from fentanyl. This is almost double the number of people who died in car accidents or from gun homicides that year.

Fentanyl has been cut into heroin for years, but now is often mixed into meth and cocaine, fueling rising death counts for those drugs, a troubling development, considering that Americans are much more likely to try meth and cocaine than heroin.

In Canada, the numbers are similarly astronomical, and fentanyl deaths have marched upward in Australia and many European countries as well. Ten years ago, fentanyl and its analogues overtook heroin to become the deadliest drug in Sweden.

“Fentanyl is the game changer,” Special Agent in Charge James Hunt of the US Drug Enforcement Administration (DEA) told Vice News. “It’s the most dangerous substance in the history of drug tracking. Heroin and cocaine pale in comparison to how dangerous fentanyl is.”

Ben Westhoff is a best-selling investigative journalist focused on drugs, culture, and poverty. His book Fentanyl, Inc.: How Rogue Chemists Created the Deadliest Wave of the Opioid Epidemic is the bombshell first book about fentanyl. Since its publication, Westhoff has advised top government officials on the fentanyl crisis, including from the White House Office of National Drug Control Policy, U.S. Senate and House of Representatives, the U.S. embassy in Beijing, and the U.S. State Department.

His new book Little Brother: Love, Tragedy, and My Search for the Truth tells the story of his relationship with Jorell Cleveland, his longtime mentee in the Big Brothers Big Sisters program. When Jorell was murdered at age 19, and the case went cold, Ben used his skills as an investigative journalist to find the killer. It’s a three-year investigation set in the northern suburbs of St. Louis that uncovers a heartbreaking cycle of poverty, poor education, drug trafficking, and violence. Follow him at benwesthoff.substack.com and benwesthoff.com.

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Droplets of fluid have been known to hover above a hot surface, but a new experiment suggests the same can happen to tiny jets of liquid too

Today is a video day since the news is the depressing same-old-same old. Instead, I found this amazing three-minute video of a deep-sea (“benthic”) octopus, Graneledone boreopacifica, who brooded her eggs for more than FOUR YEARS (to be precise, 53 months). That is by far the record for any animal, as the video says. (The previous record for any animal was 14 months.)  Octopuses are smart, and I wonder if she got bored sitting in the same spot for all that time.

Do realize that she almost certainly had nothing to eat over that period.

As far as I know, this guarding/brooding behavior is known in all octopuses that have been studied, and the sad part is that after the babies hatch, the mother simply withers and dies. This means that females reproduce only once.

 

h/t: Matthew

A research team has succeeded in synthesizing simple, environmentally sensitive cells complete with artificial organelles. For the first time, the researchers have also been able to emulate natural cell-cell communication using these proto-cells -- based on the model of photoreceptors in the eye. This opens up new possibilities for basic research and applications in medicine.

Researchers have developed PanoRadar, a new tool to give robots superhuman vision by transforming simple radio waves into detailed, 3D views of the environment.

Researchers have developed PanoRadar, a new tool to give robots superhuman vision by transforming simple radio waves into detailed, 3D views of the environment.

When active filaments are exposed to localized illumination, they accumulate into stable structures along the boundaries of the illuminated area. Based on this fact, researchers developed a model that can be used to simulate the self-organization of thread-like living matter. This model provides important insights for potential technical applications in the formation of structures.

Researchers have developed a groundbreaking coating that could make medical devices safer for millions of patients, reducing the risks associated with blood clots and dangerous bleeding. The new material is designed to mimic the natural behavior of blood vessels so that catheters, stents, blood-oxygenation machines and dialysis machines won't trigger clotting by activating certain proteins in the blood.

Scientists have advanced their NeuroMechFly model, simulating fruit fly movement in the real world. With integrated vision and smell, NeuroMechFly v2 helps us understand brain-body coordination, setting a path for neuroengineering's role in robotics and AI.

Scientists have advanced their NeuroMechFly model, simulating fruit fly movement in the real world. With integrated vision and smell, NeuroMechFly v2 helps us understand brain-body coordination, setting a path for neuroengineering's role in robotics and AI.

An international research team has for the first time designed realistic photonic time crystals ---- exotic materials that exponentially amplify light. The breakthrough opens up exciting possibilities across fields such as communication, imaging and sensing by laying the foundations for faster and more compact lasers, sensors and other optical devices.

Researchers have developed a patch for easier and more effective treatment of psoriasis. The method may also be used in treatment of other inflammatory skin diseases.

An interdisciplinary team of researchers has developed a machine learning framework that uses limited water quality samples to predict which inorganic pollutants are likely to be present in a groundwater supply. The new tool allows regulators and public health authorities to prioritize specific aquifers for water quality testing.

Researchers have combined two gene editing methods. This enables them to quickly investigate the significance of many genetic mutations involved in the development and treatment of cancer.

The standard model for how galaxies formed in the early universe predicted that the James Webb Space Telescope (JWST) would see dim signals from small, primitive galaxies. But data are not confirming the popular hypothesis that invisible dark matter helped the earliest stars and galaxies clump together.

Inside cells, there exists an extensive system of canals known as the endoplasmic reticulum (ER), which consists of membrane-encased tubes that are partially broken down as needed -- for instance in case of a nutrient deficiency. As part of this process, bulges or protrusions form in the membrane, which then pinch off and are recycled by the cell. A study has examined this protrusion process using computer simulations. Its finding: certain structural motifs of proteins in the ER membrane play a central role in this process.