News Feeds

Is potential death worse than real death?

The post Once a Doctor Has Minimized Literal Death for Young People, Should We Value Their Opinion on Any Topic Less Consequential Than Literal Death? first appeared on Science-Based Medicine.

By now there is ample evidence not only that sexual violence was part of Hamas’s attack on Israel on October 7, but also that this violence was part of the overall plen to brutalize and humiliate the Jews.  This much has been admitted even by the United Nations, whose UN Women group took way too long to even denounce that violence.

The UN’s official report, whose summary you can find here, concludes this, though results are still coming in:

Based on the information it gathered, the mission team found clear and convincing information that sexual violence, including rape, sexualized torture, cruel, inhuman and degrading treatment has been committed against hostages and has reasonable grounds to believe that such violence may be ongoing against those still held in captivity. In line with a survivor/victim-centered approach, findings are conveyed in generic terms and details are not revealed.

In the context of the coordinated attack by Hamas and other armed groups against civilian and military targets throughout the Gaza periphery, the mission team found that there are reasonable grounds to believe that conflict-related sexual violence occurred in multiple locations during the 7 October attacks, including rape and gang-rape in at least three locations, namely: the Nova music festival site and its surroundings, Road 232, and Kibbutz Re’im. In most of these incidents, victims first subjected to rape were then killed, and at least two incidents relate to the rape of women’s corpses.

The mission team also found a pattern of victims, mostly women, found fully or partially naked, bound, and shot across multiple locations. Although circumstantial, such a pattern may be indicative of some forms of sexual violence, including sexualized torture, cruel, inhuman and degrading treatment.

. . .Overall, the mission team is of the view that the true prevalence of sexual violence during the 7 October attacks and their aftermath, may take months or years to emerge and may never be fully known.

Although the report has a bit of both-sideism by mentioning “allegations of conflict-related sexual violence” committed by “Israeli security forces and settlers,” none of that has been documented. Although those allegations persist, most, at least since October 7, have been retracted—even by Hamas.

Nevertheless, part of the attack on Israel is “rape denialism”: either denying that any sexual violence took place (“no proof,” some people say), or to admit that there may have been a small amount, but it was ancillary and not part of the strategy of Hamas (here’s one example of that denialism). The denialism is, of course, part of the denigration of Israel and Jews that has followed October 7.

If you have any doubts about the existence or extent of sexual violence, read the full UN report, remembering that the UN investigatory visit to Israel took place mostly during February of this year. But first, I’d highly recommend that you watch this hourlong movie, “Screams Before Silence”. Created by Sheryl Sandberg; it received its premiere just two days ago and has already been made public for free.  I’m putting the link here and urge you to watch it, even if you’re squeamish. It is immensely moving, disturbing, and yet heartening as the survivors struggle to tell their tale because they want people to know what happened. Most of all, it’s convincing.

As the Times of Israel reports about the movie,

The hour-long film, created in cooperation with Israel’s Kastina Productions, provides first-hand accounts from survivors, freed hostages, first responders, and legal, medical, and forensic experts. Sandberg is present throughout the film either interviewing individuals in a studio or accompanying them to October 7-related sites.

What emerges is not only an understanding of the mass scale and barbarism of Hamas’s sexual attacks against women but also their deliberate, pre-meditated, and systematic nature.

“When the body of the woman is violated, it symbolizes [the violation] of the body of the whole nation,” Prof. Ruth Halperin-Kaddari, former vice-president of the United Nations Commission on the Elimination of Discrimination Against Women, says in the documentary.

The film’s testimonies detail a horrific truth that was largely brushed aside by a report released earlier this week by United Nations Secretary-General Antonio Guterres, in which he declined to include Hamas among organizations suspected by the UN of committing acts of sexual violence during conflict. That report noted there is evidence that sex crimes were committed during the Palestinian terror group’s devastating October 7 attack on Israel, but did not specifically attribute responsibility to Hamas.

Guterres is, of course, an odious, Israel-hating git, and that’s nowhere better demonstrated than in his refusal even now to admit that Hamas committed sexual violence during its attack. (It also, as you’ll see in the movie, did so to some of the hostages.)  Since many of the victims are dead, and there is still a dearth of witnesses, much less bodies that can give evidence of rape or other sexual violence, there is certainly enough to buttress the UN’s report—and to show Guterres up as the liar he is.

But I digress. In this movie, which you can see by clicking below, Sandberg largely stands aside but listens as survivors, witnesses, and forensic experts tell the story. If this doesn’t move and anger you, well, I don’t know how that could happen to anyone with a heart.

Click below and then on the “watch full film” box. NOTE:  Some of the material is not for those who can’t bear to hear about the often horrible violence done to women. As I said, if you are squeamish about that, you might not want to watch.  I was horrified at some parts, but I also think that one can’t comprehend such a phenomenon without confronting it directly rather than through words like “sexual violence happened.” But your mileage may vary.

John Oliver and UFOs; News Items: Voyager Fixed, NASA's New Solar Sail, Bird Flu in Milk, Dark Energy Getting Weaker, After Death Communications; Who's That Noisy; Your Questions and E-mails: Havana Syndrome; Science or Fiction

It’s time for Caturday again.

First, from Cole and Marmalade, we have, yes, a page devoted to chirping cats. You can find anything on the internet.

Click to read:

An excerpt:

People absolutely love it when cats do the funny sound that’s become known as ‘Ekekek.’ We usually call it chattering, the strange sound that cats often make when they see a bird from the window. Others call it chirping, similar to trilling. They often do it when they see another cat outside.

Sometimes, they do it for no apparent reason at all, like Jugg below!

Video by Cole and Marmalade featuring our own Jugg of Jugg and Zig Zag:

The chirping is also known as “machine-gunning,” and is often seen when a cat spies a bird outside the window:

More videos of cats making “that noise”:

. . . and cats chattering en masse:

*********************

Here a cat bullies a husky, going for the d*g’s ears and muzzle. As you expect, the d*g doesn’t like it. But the husky doesn’t try to hurt the moggy.

*****************

The Rijksmuseum in Amsterdam, a gold mine of Dutch art, is most famous for housing Rembrandt.  And I’ll be going there in about two weeks. The museum itself, though, has put up a post showing ten of its most popular cat paintings, which you can see by clicking below. I’ve singled out five.

Detail from “The Fall of Man” by Cornelis Corneliszoon van Haarlem, 1592 (full painting here).  This is apparently the most popular depiction of a cat in the museum.

Cornelis van Haarlem, Public domain, via Wikimedia Commons

“Children Teaching a Cat to Dance“, by Jan Steen, painted 1660-1679. A detail is below; the cat clearly doesn’t like it:

Detail:

“Dog and Cat Dancing”, attributed to Adriaen Matham after Adriaen Pietersz. van de Venne, 1620 – 1660. Source, Rijksmuseum site.

Cat by Anselmus de Boodt (1550-1632). From rawpixel.com:

Henriëtte Ronner-Knip (1821-1909), “Kittens at Play”. I’m not sure this one is in the Rijksmuseum, but other cat paintings by the artist are.

*****************

Lagniappe:  In footage captured from a ring camera, a cat fights off black bear:

h/t: Matthew

Today is part 2 of photos of a part in southern Africa from reader William Terre Blanche; this is the second of two installments (the first is here).  His notes are indented, and you can enlarge the photos by clicking on them. I begin by quoting his introduction from yesterday:

Here are some photos from a visit last year to the Kgalagadi Transfrontier Park  (Kgalagadi means “place of great thirst” in the San Language).

This vast wilderness reserve used to comprise two separate game parks, the Kalahari Gemsbok National Park (South Africa) and the Gemsbok National Park (Botswana) separated by an unfenced border. However, in a historic 1999 agreement, South Africa and Botswana joined forces to create the world’s first trans-frontier nature reserve, the Kalagadi Transfrontier Park. It covers an amazing 38,000 km², an enormous conservation area across which the wildlife flows without any hindrance.

The Park is famous for its magnificent black-maned male lions, as well as an abundance of raptor species, but the beautiful desert landscape and unique atmosphere is probably what draws most return visitors there (myself included).

In December 2023, I had the privilege of spending almost 2 weeks in the park, and these are just some of the many photographs taken there (apologies, mostly birds, again..).

Three-banded Plover (Charadrius tricollaris)  These can often be seen using the typical plover run-stop-search method of foraging at any suitable body of water. The area had unusually good summer rains last year, and these pretty little birds were often seen:

Violet-eared Waxbill (Ureaginthus granatinus).  An almost impossibly brightly coloured little bird, they are actually quite common in the Kgalagadi, but the vibrant colours never ceases to amaze me whenever I come across one of them:

Sociable Weaver (Philetairus socius).  One of the most iconic sights of the Kgalagadi Transfrontier Park is the massive communal nests of the Sociable Weaver. Colonies of up to 500 birds build these nests in trees, telephone poles and sometimes rock faces. The nests are built entirely out of grass, and each pair builds its own nest chamber:

Northern Black Korhaan (Afrotis afraoides). Their raucous kraak-kraak-kraak call is often heard long before they are seen! Spends most of the day on the ground, searching for food which is mostly insects and occasionally small reptiles:

Cheetah (Acinonyx jubatus).  The world’s fastest land animal and Africa’s most endangered big cat. This female was presumably calling for the young, although I unfortunately never got to see them:

Urikaruus Wilderness Camp.  There are 3 main “Restcamps” inside the Park, plus a number of so-called Wilderness Camps. There are normally well off the beaten track, and mostly only reachable by 4×4 vehicle. There are no facilities whatsoever at these camps, so you have to be completely self-sufficient during the time spent there:

Male Lion (Panthera leo).  I spent a couple of nights at the abovementioned Urikaruus Wilderness Camp, and on the second morning was awakened at around 04:30 by a male lion roaring right under the room where I was sleeping (next to my car, in the picture below). This was at the same time exciting and terrifying, but one of the memories that will stay with me for life.

After a while he started moving away, and I was able to get a photograph of this magnificent animal:

Lioness:

Cubs.  On another occasion I spotted a single female lion lying in the shade of the tree a small distance from the road. After a couple of minutes she started calling, and these two cubs appeared from a nearby bush to join her. I can only assume that she had hidden them there, and after determining that the area was safe called them out into the open.

https://traffic.libsyn.com/secure/sciencesalon/mss426_Robin_Reames_2024_04_27.mp3 Download MP3

The discipline of rhetoric was the keystone of Western education for over two thousand years. Only recently has its perceived importance faded.

In this book, renowned rhetorical scholar Robin Reames argues that, in today’s polarized political climate, we should all care deeply about learning rhetoric. Drawing on examples ranging from the destructive ancient Greek demagogue Alcibiades to modern-day conspiracists like Alex Jones, Reames breaks down the major techniques of rhetoric, pulling back the curtain on how politicians, journalists, and “journalists” convince us to believe what we believe—and to talk, vote, and act accordingly. Understanding these techniques helps us avoid being manipulated by authority figures who don’t have our best interests at heart. It also grants us rare insight into the values that shape our own beliefs. Learning rhetoric, Reames argues, doesn’t teach us what to think but how to think—allowing us to understand our own and others’ ideological commitments in a completely new way.  Thoughtful, nuanced, and leavened with dry humor, The Ancient Art of Thinking for Yourself offers an antidote to our polarized, post-truth world. 

Robin Reames is associate professor of English at the University of Illinois at Chicago, specializing in rhetorical theory and the history of ideas. She teaches graduate and undergraduate courses in contemporary and ancient rhetorical theory, language theory, rhetorical criticism, political rhetoric, writing, as well as courses in literature and literary theory. Her research is guided by an interest in the visceral and primordial power of human speech, for which ancient rhetoric serves as a first theory. Her book, Seeming and Being in Plato’s Rhetorical Theory examines how Plato used rhetorical theory to forge the primordial distinction between seeming and being—the foundational fissure from which Western metaphysics emerged, and the very grounds of the opposition between true and false. Her new book is The Ancient Art of Thinking For Yourself: The Power of Rhetoric in Polarized Times.

Reames and Shermer discuss:

• What is rhetoric?
• How has rhetoric changed her life?
• Rhetoric vs. facts (rhetorical truths vs. empirical truths)
• Is the point of reason to understand reality or to persuade? (Hugo Mercier/Dan Sperber, The Enigma of Reason)
• Canons of rhetoric: invention, arrangement, style, memory, delivery
• “Through thinking rhetorically about our ideological commitments it is possible for people from radically different orientations to have different, better, and more productive conversation.”
• Logos (authority), pathos (feelings), ethos (ethics), hubris (pride)
• Bullshitters vs. liars
• What is reason?
• Induction and deduction
• What is truth?
• Can you reason people out of beliefs they didn’t reason themselves into?
• Thinking rhetorically rather than ideologically
• Thinking metaphorically: “war on poverty”, “government as family” (George Lakoff)
• Thought and language
• Thought, language, and ideology
• How language is processed (thoughts vs. pictures)
• How to disagree with people/debate hot issues (guns, abortion, immigration)
• Culture wars: war between two different cultures—liberal and conservative
• How to have impossible conversations
• Toulmin scheme: data, claim, warrant, backing, qualifier, rebuttal
• Facts and values
• Value hierarchy
• Warrant: linking data to a claim
• Syllogistic reasoning/deduction
• Conspiracy theories and why people believe them
• Birtherism and Trutherism.

If you enjoy the podcast, please show your support by making a $5 or $10 monthly donation.

Any event in the cosmos generates gravitational waves, the bigger the event, the more disturbance. Events where black holes and neutron stars collide can send out waves detectable here on Earth. It is possible that there can be an event in visible light when neutron stars collide so to take advantage of every opportunity an early warning is essential. The teams at LIGO-Virgo-KAGRA observatories are working on an alert system that will alert astronomers within 30 seconds fo a gravity wave event. If warning is early enough it may be possible to identify the source and watch the after glow. 

The very fabric of space-time can be thought of as a giant celestial ocean. Any movement within the ocean will generate waves. The same is true of movements and disturbances in space, causing a compression in one direction while stretching out in the perpendicular direction. Modern gravity wave detectors are usually L-shaped with beams shining down each arm of the building. The two beams are combined and the interference patterns are studied allowing the lengths of the two beams to be accurately calculated. Any change suggests the passage of a gravity wave. 

LIGO Observatory

A team of researchers at the University of Minnesota have run a study that endeavours to improve the detection of the waves. Not only do they hope to improve the detection itself but also to establish an alerting mechanism so that astronomers get a notification within 30 seconds after the event detection. 

The team used data from previous observations and created simulated gravity wave signal data so that they could test the system. But it is far more than just an alerting system. Once fully operational, it will be able to detect the shape of the signals, track how it evolves over time and even provide an estimate of the properties of the individual components that led to the waves. 

After it is fully operational, the software would detect the wave for example from neutron star or black hole collisions. The former usually too faint to be able to detect unless its location is known precisely. It would generate an alert from the wave to help precisely pinpoint the location giving an opportunity for follow up study. 

Light bursts from the collision of two neutron stars. Credit: NASA’s Goddard Space Flight Center/CI Lab

There are still many outstanding questions surrounding neutron star and black hole formation not least of which is the exact mechanism that leads to the formation of gold and uranium. 

graThe LIGO (Laser Interferometer Gravitational-Wave Observatory) has just finished its latest run but the next is due in February 2025. Between recent observing runs, enhancements and improvements have been made to improve the capability of detecting signals. Eventually of course it comes down to the data and once the current run ends, the teams will get started. 

Source : Researchers advance detection of gravitational waves to study collisions of neutron stars and black holes

The post Astronomers Will Get Gravitational Wave Alerts Within 30 Seconds appeared first on Universe Today.

As the US grapples with an ongoing bird flu outbreak in dairy cattle, the country’s health agencies are ramping up surveillance efforts and working to develop a vaccine if needed

Commercial bowhead whaling ended in the early 20th century, but the industry’s lasting effects on the whales’ genetic diversity are leading to declines again

During the Space Race, scientists in both the United States and the Soviet Union investigated the concept of ion propulsion. Like many early Space Age proposals, the concept was originally explored by luminaries like Konstantin Tsiolkovsky and Hermann Oberth – two of the “forefathers of rocketry.” Since then, the technology has been validated repeatedly by missions like the Deep Space-1 (DS-1) technology demonstrator, the ESA’s Smart-1 lunar orbiter, JAXA’s Hayabusa and Hayabysa 2 satellites, and NASA’s Dawn mission.

Looking to the future of space exploration, researchers at the NASA Glenn Research Center (GRC) have been busy developing a next-generation ion engine that combines extreme fuel efficiency with high acceleration. These efforts have led to the NASA-H71M sub-kilowatt Hall-effect thruster, a small spacecraft electric propulsion (SSEP) system that will enable new types of planetary science missions. With the help of commercial partners like SpaceLogistics, this thruster will also be used to extend the lifetimes of spacecraft that are already in orbit.

Space exploration and commercial space have benefitted from the development of small spacecraft and small satellites. These missions are notable for being cost-effective since they require less propellant to launch, can be deployed in smarms, and take advantage of rideshares. Similarly, the proliferation of small satellite constellations in Low Earth Orbit (LEO) has made low-power Hall-effect thrusters the most common electric propulsion system in space today. These systems are noted for their fuel efficiency, allowing many years of orbital maneuvers, corrections, and collision avoidance.

Nevertheless, small spacecraft will need to be able to perform challenging propulsive maneuvers like achieving escape velocity, orbital capture, and other maneuvers that require significant acceleration (delta-v). The thrust required to perform these maneuvers – 8 km/s (~5 mps) of delta-v – is beyond the capability of current and commercially available propulsion technology. Moreover, low-cost commercial electric propulsion systems have limited lifetimes and typically process only about 10% of a small spacecraft’s propellant mass.

Similarly, secondary spacecraft are becoming more common thanks to rockets with excess capacity (enabling rideshare programs). Still, these are generally limited to scientific targets that align with the primary mission’s trajectory. Additionally, secondary missions typically have limited time to collect data during high-speed flybys. What is needed is an electric propulsion system that requires low power (sub-kilowatt) and has high-propellant throughout – meaning it is capable of using lots of propellant over its lifetime.

To meet this demand, engineers at NASA Glenn are taking many advanced high-power solar electric propulsion (SEP) elements developed over the past decade and are miniaturizing them. These elements were developed as part of NASA’s Moon to Mars mission architecture, with applications including the Power and Propulsion Element (PPE) of the Lunar Gateway. A SEP system was also part of the design for a Deep Space Transport (DST), the vehicle that will conduct the first crewed missions to Mars by 2040. The NASA-H71M system, however, is expected to have a major impact on small spacecraft, expanding mission profiles and durations.

According to NASA, missions using the NASA-H71M system could operate for 15,000 hours and process over 30% of the small spacecraft’s initial mass in propellant. This system could increase the reach of secondary spacecraft, allowing them to deviate from the primary mission’s trajectory and explore a wider range of scientific targets. By allowing spacecraft to decelerate and make orbital insertions, this technology could increase mission durations and the amount of time they have to study objects.

NASA-H71M Hall-effect thruster on the Glenn Research Center Vacuum Facility 8 thrust stand (left) and Dr. Jonathan Mackey tuning the thrust stand before closing and pumping down the test facility (right). Credit: NASA GRC

It’s also beyond the needs of most commercial LEO missions, and the associated costs are generally higher than what commercial missions call for. As such, NASA continues to seek partnerships with commercial developers working on small commercial spacecraft with more ambitious mission profiles. One such partner is SpaceLogistics, a wholly owned subsidiary of Northrop Grumman that provides in-orbit satellite servicing to geosynchronous satellite operators using its proprietary Mission Extension Vehicle (MEV).

This vehicle relies on Northrop Grumman NGHT-1X Hall-effect thrusters based on the NASA-H71M design. This propulsive capability will allow the MEV to reach satellites in Geosynchronous Earth Orbit (GEO), where it will dock with customer’s satellites, extending their lives for at least six years. Through a Space Act Agreement (SAA), Northrop Grumman is conducting long-duration wear tests (LDWT) at NASA Glenn’s Vacuum Facility 11. The first three MEP spacecraft are expected to launch in 2025 and extend the lives of three GEO communication satellites.

Further Reading: NASA

The post Next Generation Ion Engines Will Be Extremely Powerful appeared first on Universe Today.

Researchers have found two novel types of attacks that target the conditional branch predictor found in high-end Intel processors, which could be exploited to compromise billions of processors currently in use.

A new algorithm can identify the most predictive data points that a tipping point is near.

Researchers have demonstrated that ferromagnetism, an ordered state of atoms, can be induced by increasing particle motility and that repulsive forces between atoms are sufficient to maintain it. The discovery not only extends the concept of active matter to quantum systems but also contributes to the development of novel technologies that rely on the magnetic properties of particles, such as magnetic memory and quantum computing.

Researchers have demonstrated that ferromagnetism, an ordered state of atoms, can be induced by increasing particle motility and that repulsive forces between atoms are sufficient to maintain it. The discovery not only extends the concept of active matter to quantum systems but also contributes to the development of novel technologies that rely on the magnetic properties of particles, such as magnetic memory and quantum computing.

Researchers have developed a new PCB that performs on par with traditional materials and can be recycled repeatedly with negligible material loss. Researchers used a solvent that transforms a type of vitrimer -- a cutting-edge class of polymer -- into a jelly-like substance without damage, allowing solid components to be plucked out for reuse or recycling. With these 'vPCBs' (vitrimer printed circuit boards), researchers recovered 98% of the vitrimer and 100% of the glass fiber.

Researchers have developed a new PCB that performs on par with traditional materials and can be recycled repeatedly with negligible material loss. Researchers used a solvent that transforms a type of vitrimer -- a cutting-edge class of polymer -- into a jelly-like substance without damage, allowing solid components to be plucked out for reuse or recycling. With these 'vPCBs' (vitrimer printed circuit boards), researchers recovered 98% of the vitrimer and 100% of the glass fiber.

Researchers have created TopicVelo, a powerful new method of using the static snapshots from scRNA-seq to study how cells and genes change over time. This will help researchers better study how embryos develop, cells differentiate, cancers form, and the immune system reacts.

The Milky Way has a missing pulsar problem in its core. Astronomers have tried to explain this for years. One of the more interesting ideas comes from a team of astronomers in Europe and invokes dark matter, neutron stars, and primordial black holes (PBHs).

Astronomer Roberto Caiozzo, of the International School for Advanced Studies in Trieste, Italy, led a group examining the missing pulsar problem. “We do not observe pulsars of any kind in this inner region (except for the magnetar PSR J1745-2900),” he wrote in an email. “This was thought to be due to technical limitations, but the observation of the magnetar seems to suggest otherwise.” That magnetar orbits Sagittarius A*, the black hole at the core of the Milky Way.

An x-ray map of the core of the Milky Way showing the position of the recently discovered magnetar orbiting the supermassive black hole Sgr A*. Courtesy Chandra and XMM-Newton.

The team examined other possible reasons why pulsars don’t appear in the core and looked closely at matnetar formation as well as disruptions of neutron stars. One intriguing idea they examined was the cannibalization of primordial black holes by neutron stars. The team explored the missing-pulsar problem by asking the question: could neutron star-primordial black hole cannibalism explain the lack of detected millisecond pulsars in the core of the Milky Way? Let’s look at the main players in this mystery to understand if this could happen.

Neutron Stars, Pulsars, and Little Black Holes, Oh My

Theory suggests that primordial black holes were created in the first seconds after the Big Bang. “PBHs are not known to exist,” Caiozzo points out, “but they seem to explain some important astrophysical phenomena.” He pointed at the idea that supermassive black holes seemed to exist at very early times in the Universe and suggested that they could have been the seeds for these monsters. If there are PHBs out there, the upcoming Nancy Grace Roman Telescope could help find them. Astronomers predict they could exist in a range of masses, ranging from the mass of a pin to around 100,000 the mass of the Sun. There could be an intermediate range of them in the middle, the so-called “asteroid-mass” PBHs. Astronomers suggest these last ones as dark matter candidates.

Primordial black holes, if they exist, could have formed by the collapse of overdense regions in the very early universe. Credit M. Kawasaki, T.T. Yanagida.

Dark matter makes up about 27 percent of the Universe, but beyond suggesting that PBH could be part of the dark matter content, astronomers still don’t know exactly what it is. There does seem to be a large amount of it in the core of our galaxy. However, it hasn’t been directly observed, so its presence is inferred. Is it bound up in those midrange PBHs? No one knows.

The third player in this missing pulsar mystery is neutron stars. They’re huge, quivering balls of neutrons left over after the death of a supergiant star of between 10 and 25 solar masses. Neutron stars start out very hot (in the range of ten million K) and cool down over time. They start out spinning very fast and they do generate magnetic fields. Some emit beams of radiation (usually in radio frequencies) and as they spin, those beams appear as “pulses” of emission. That earned them the nickname “pulsar”. Neutron stars with extremely powerful magnetic fields are termed “magnetars”.

Pulsars are fast-spinning neutron stars that emit narrow, sweeping beams of radio waves. A new study identifies the origin of those radio waves. NASA’s Goddard Space Flight Center The Missing Pulsar Problem

Astronomers have searched the core of the Milky Way for pulsars without much success. Survey after survey detected no radio pulsars within the inner 25 parsecs of the Galaxy’s core. Why is that? Caizzo and his co-authors suggested in their paper that magnetar formation and other disruptions of neutron stars that affect pulsar formation don’t exactly explain the absence of these objects in the galactic core. “Efficient magnetar formation could explain this (due to their shorter lifetime),” he said, “But there is no theoretical reason to expect this. Another possibility is that the pulsars are somehow disrupted in other ways.”

Usually, disruption happens in binary star systems where one star is more massive than the other and it explodes as a supernova. The other star may or may not explode. Something may kick it out of the system altogether. The surviving neutron star becomes a “disrupted” pulsar. They aren’t as easily observed, which could explain the lack of radio detections.

If the companion isn’t kicked out and later swells up, its matter gets sucked away by the neutron star. That spins up the neutron star and affects the magnetic field. If the second star remains in the system, it later explodes and becomes a neutron star. The result is a binary neutron star. This disruption may help explain why the galactic core seems to be devoid of pulsars.

Using Primordial Black Hole Capture to Explain Missing Pulsars

Caizzo’s team decided to use two-dimensional models of millisecond pulsars—that is, pulsars spinning extremely fast—as a way to investigate the possibility of primordial black hole capture in the galactic core. The process works like this: a millisecond pulsar interacts in some way with a primordial black hole that has less than one stellar mass. Eventually, the neutron star (which has a strong enough gravitational pull to attract the PBH) captures the black hole. Once that happens, the PBH sinks to the core of the neutron star. Inside the core, the black hole begins to accrete matter from the neutron star. Eventually, all that’s left is a black hole with about the same mass as the original neutron star. If this occurs, that could help explain the lack of pulsars in the inner parsecs of the Milky Way.

Could this happen? The team investigated the possible rates of capture of PBHs by neutron stars. They also calculated the likelihood that a given neutron star would collapse and assessed the disruption rate of pulsars in the galactic core. If not all the disrupted pulsars are or were part of binary systems, then that leaves neutron star capture of PBHs as another way to explain the lack of pulsars in the core. But, does it happen in reality?

Missing Pulsar Tension Continues

It turns out that such cannibalism cannot explain the missing pulsar problem, according to Caizzo. “We found that in our current model PBHs are not able to disrupt these objects but this is only considering our simplified model of 2 body interactions,” he said. It doesn’t rule out the existence of PHBs, only that in specific instances, such capture isn’t happening.

So, what’s left to examine? If there are PHBs in the cores and they’re merging, no one’s seen them yet. But, the center of the Galaxy is a busy place. A lot of bodies crowd the central parsecs. You have to calculate the effects of all those objects interacting in such a small space. That “many-body dynamics” problem has to account for other interactions, as well as the dynamics and capture of PBHs.

Astronomers looking to use PBH-neutron star mergers to explain the lack of pulsar observations in the core of the Galaxy will need to better understand both the proposed observations and the larger populations of pulsars. The team suggests that future observations of old neutron stars close to Sgr A* could be very useful. They’d help set stronger limits on the number of PBHs in the core. In addition, it would be useful to get an idea of the masses of these PBHs, since those on the lower end (asteroid-mass types) could interact very differently.

For More Information

Revisiting Primordial Black Hole Capture by Neutron Stars
Searching for Pulsars in the Galactic Centre at 3 and 2 mm

The post Neutron Stars Could be Capturing Primordial Black Holes appeared first on Universe Today.

To celebrate the launch of our new event series in the US, kicking off with a masterclass on the brain and consciousness, we have unlocked five incredible long reads

The genetic variant, which causes people to be insensitive to growth hormone, may also protect people from heart disease