Science

The problem with debating a flat-Earther is that they didn’t arrive at their conclusions from the weight evidence, so using the evidence isn’t going to work to change their minds.

That said, the evidence for the curved Earth is abundant. Besides the enormous body of photographic documentation, it’s even possible to do the experiment yourself. For example, I recently flew from New York City to Doha, from there to Singapore, then to Brisbane, then to Dallas, then back home. I followed an eastward course for my entire journey, and ended up back where I started. That’s only possible on a globe.

On that journey I got to enjoy plenty of views of the night sky, and one of the most striking features was that the sky was different. On a flat Earth, everyone would get the same view of the sky, but there were stars that I could only see at home and couldn’t on my trip, and vice versa.

And lastly, during a lunar eclipse the shadow of the Earth passes over the Moon. That shadow is always a circle, and only spheres are capable of casting circular shadows 100% of the time, regardless of angle.

But like I said, it’s not about the evidence. People who believe that the Earth is flat think that we are being lied to by scientists and political leaders. Many people don’t trust their society, and especially leaders of that society. And most especially elite leaders of that society. Scientists are indeed elite leaders of the government, academia, and other powerful institutions. By claiming that the Earth is flat, people are really expressing a deep distrust of scientists and science itself.

Distrust in science is a deep, thorny issue. But one way to rebuild trust is to simply listen. I know it sounds counter-intuitive, but studies have shown that people tend to trust other people, not necessarily the facts. So if you encounter a flat-Earth, as I have many times, don’t bother getting in a debate. Instead, change the subject so that you focus on something you find wonderful or extraordinary about the universe or about science. Maybe it’s an exciting new observation, or a clever experimental result, or an example of a real-world impact from scientific learning.

By building bridges based on shared wonder, awe, and curiosity, we can defuse the tension, moving around the flashpoint caused by a triggering proclamation and instead focusing on common ground. That’s the only place where trust can take root. And once trust is established, the question of the geometry of the Earth simply fades into the background.

The post How to Debate a Flat-Earther appeared first on Universe Today.

Researchers have developed a drastically smaller and more energy efficient method of creating coveted photon pairs that influence each other from any distance. The technology could transform computing, telecommunications, and sensing.

Researchers have developed a drastically smaller and more energy efficient method of creating coveted photon pairs that influence each other from any distance. The technology could transform computing, telecommunications, and sensing.

Although extremely flammable, cotton is one of the most commonly used textiles due to its comfort and breathable nature. However, in a single step, researchers can reduce the flammability of cotton using a polyelectrolyte complex coating.

The traditional theory of black hole formation seems to struggle to explain how black holes can merge into larger more massive black holes yet they have been seen with LIGO. It’s possible that they may have formed at the beginning of time and if so, then they may be a worthy candidate to explain dark matter but only if there are enough of them. A team of researchers recently searched for microlensing events from black holes in the Large Magellanic Cloud but didn’t find enough to account for more than a fraction of dark matter. 

Classical black hole formation theory explains how they from the remnants of massive stars that have reached the end of their life and exhausted their fuel. When a star with a mass greater than about 20 times that of the Sun reaches the end of its life, it undergoes a supernova explosion, ejecting most of its outer layers into space. 

3D rendering of a rapidly spinning black hole’s accretion disk and a resulting black hole-powered jet. Credit: Ore Gottlieb et al. (2024)

The core that is left behind is no longer supported by the pressure from nuclear fusion so it collapses under its own gravity. If the core’s mass is sufficient, typically several times the mass of the Sun, it will continue to collapse into a singularity—an infinitely dense point with an extremely strong gravitational pull. This process creates a black hole, characterised by the event horizon, a boundary beyond which nothing, not even light, can escape its gravity.

That’s a widely accepted description of the formation of black holes. However a recent set of observations using gravity wave detectors has identified some massive black holes. When compared to those that can be seen in the Milky Way they bare little resemblance. One possible explanation suggests that they may have instead formed from fluctuations in density during an earlier part of the universe’s history. These are known as primordial black holes and some theories suggest that they may account for dark matter. Possibly even up to 100% of the dark matter to account for the observed black hole merger rates. If they exist in the dark matter halo of the Milky Way then they should be observable by gravitational microlensing events. 

Image from NASA’s Hubble Space Telescope of a galaxy cluster that could contain dark matter (blue-shaded region). (Credit: NASA, ESA, M. J. Jee and H. Ford et al. (Johns Hopkins Univ.))

Previous studies have failed to identify such events but the team believe the observations were not sensitive enough. The paper published by Przemek Mroz from the University of Warsaw and team offer their findings of long-timescale microlensing events (events that occur over extended periods of times from weeks sometimes even years) in the Large Magellanic Cloud over the 20 years of the OGLE (Optical Gravitational Lensing Experiment) survey. The survey began in 1992 and is a long term study to detect microlensing events and observe variable phenomenon such as variable stars and supernova. It’s based at the Las Campanas Observatory in Chile and using the 1.3 metre telescope to monitor sections of sky. 

The Large Magellanic cloud. Credit: CTIO/NOIRLab/NSF/AURA/SMASH/D. Nidever (Montana State University) Image processing: Travis Rector (University of Alaska Anchorage), Mahdi Zamani & Davide de Martin.

Having analysed the 20 years of data they found no events within the timescales longer than a year. Other shorter period events were identified but these are more likely down to stellar events than supermassive primordial black holes (PMB.) They find therefore, that PMB’s up to 6.3 million solar masses cannot make up more than 1% of dark matter. Those in the larger category up to 860 million solar masses cannot compose any more than 10% of dark matter. The unmistakable conclusion is that PMBs, based on the observations in the Large Magellanic Cloud, cannot account for a significant fraction of dark matter.

Source : No massive black holes in the Milky Way halo

The post LIGO Has Detected Unusual Black Holes Merging, But they Probably Don’t Explain Dark Matter appeared first on Universe Today.

Fast Radio Bursts (FRBs) are mysterious pulses of energy that can last from a fraction of a millisecond to about three seconds. Most of them come from outside the galaxy, although one has been detected coming from a source inside the Milky Way. Some of them also repeat, which only adds to their mystery.

Though astrophysicists think that a high-energy astrophysical process is the likely source of FRBs, they aren’t certain how they’re generated. Researchers used gravitational waves (GWs) to observe one nearby, known source of FRBs to try to understand them better.

The only confirmed FRB source in the Milky Way is a neutron star with a powerful magnetic field—a magnetar—named SGR 1935+2154. Its FRB was detected in 2020 and was the first one to be connected to a source. Though SGR 1935+2154 is around 20,000 light-years away, it’s still close enough to be studied.

In new research in The Astrophysical Journal, scientists used the British-German GEO600 gravitational wave detector to probe any connections between the FRBs and gravitational waves. The research is “A Search Using GEO600 for Gravitational Waves Coincident with Fast Radio Bursts from SGR 1935+2154,” and the lead author is A. G. Abac. Abac is from the Max Planck Institute for Gravitational Physics.

FRBs are extraordinarily energetic, and so are magnetars. Connecting an FRB with the magnetar SGR 1935-2154 is a big step in understanding FRBs, although there are still a whole host of unanswered questions. Some magnetars repeatedly emit FRBs and also glow in X-rays. Magnetars can experience powerful star quakes when tension in their crusts is released, and the released energy shakes the magnetar’s magnetic field, releasing the FRBs and X-rays. Researchers have wondered if those same quakes might generate gravitational waves.

Artist’s conception of a starquake cracking the surface of a neutron star. Credit: Darlene McElroy of LANL

Can observing the magnetar for GWs open a window into magnetars and the processes that generate FRBs?

“Observing fast radio bursts and gravitational waves from a magnetar at almost simultaneously would be the evidence we have been looking for for a long time,” said James Lough, lead scientist of the German-British gravitational-wave detector GEO600 at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute; AEI) in Hanover. A simultaneous observation of FRBs and GWs could confirm the common origin in the stellar quakes generated by the neutron star. “That’s why we worked with an international team to analyze data we took with GEO600 while a magnetar on our cosmic doorstep was emitting fast radio bursts,” adds Lough.

If the magnetar is generating GWs, they’ll be strong when they reach our detectors, and their effects should be easier to observe. Between April 2020 and October 2022, SGR 1935+2154 generated three episodes of FRBs, and GEO600 was listening. The GW detector is part of the global network of GW detectors.

The GEO600 GW detector is near Hanover, Germany. While other GW detectors suffered shutdowns during the COVID-19 pandemic, GEO600 continued to operate. LIGO, for example, resumed operations post-pandemic, including some new upgrades. Image Credit: Max Planck Institute for Gravitational Physics (Albert Einstein Institute)/Milde Marketing

“It was essential that GEO600 could continue observing while all the other detectors were in an upgrade phase,” explained Lough. “Otherwise, we would have missed the opportunity of having gravitational-wave data during these fascinating events occurring so close to us.”

Unfortunately, careful analysis of GEO600’s data showed no evidence of GWs. However, the detector’s observations were still valuable. Since the magnetar is so close to us, even the lack of detection provided some new information.

This isn’t the first time that scientists have used GW detectors to search for GWs emitted simultaneously with FRBs, as well as for GWs from magnetar bursts and pulsar glitches. Different researchers have used the more powerful LIGO, Virgo, and KAGRA (LVK) collaborations to find them without success. “While no detections were found in these studies, the searches have established upper limits on GW energy that may have been emitted in association with these events,” the authors write in their research.

This illustration shows the merger of two supermassive black holes and the gravitational waves that ripple outward as the black holes spiral toward each other. Image Credit: LIGO/T. Pyle

The LVK detectors are larger and more powerful than GEO600. Their data shows that the maximum possible gravitational-wave energy that could have been emitted during the magnetar’s 2020 to 2022 FRBs without being detected must have been up to 10,000 times smaller than astronomers had concluded from previous studies.

Different models explain how GWs are produced in FRBs, and the GW observations aren’t yet sensitive enough to distinguish between them. However, by establishing limits for the strength of the GWs, the GW observations are still providing information that is helping scientists refine their models.

The attempt to link GWs and FRBs is really only beginning. While LIGO/Virgo weren’t able to observe the magnetar during its last FRBs, they will hopefully be operational during the next episode. This time, their effectiveness and sensitivity will have been upgraded.

For a long time, astrophysicists have theorized that magnetars are the source of FRBs, and the detection of FRBs from SGR 1935+2154 confirms this, at least for some FRBs. However, the exact mechanism behind their generation remains elusive. “The relationship between these magnetar bursts and FRBs is poorly understood, but are likely to be caused by different physical processes, even if the underlying magnetar behaviour may be related,” the authors write in their conclusion.

If future GW observations of the magnetar with the upgraded LIGO/Virgo and KAGRA observatories can show that GWs are emitted simultaneously with FRBs, that will be a huge development. “Given the increased sensitivity of these detectors compared to GEO600, any SGR 1935+2154 FRB during the remainder of O4 (Observing Run 4) could provide another opportunity to probe the GW-FRB connection,” the authors of the study explain.

“Things could get exciting really soon. We hope that the magnetar, which has been quiet for two years and has not emitted any radio bursts, will become active again in the next few months,” says Karsten Danzmann, director at the AEI and director of the Institute for Gravitational Physics at Leibniz University Hannover. The international detector network is partway through an observing run that will continue until June 2025. “With the data from the more sensitive instruments, we will be able to look even more closely whether the fast radio burst of magnetars are accompanied by gravitational waves and thus perhaps solve a very old mystery,” says Danzmann.

The post Gravitational Waves Could Give Us Insights into Fast Radio Bursts appeared first on Universe Today.

Last year, Meta allowed thousands of paid ads containing sexually explicit imagery on social media platforms, including Facebook and Instagram

Volcanoes have been proposed as the reason for the extinction of the Neanderthals and the hobbits of Indonesia, but the end of those species may not have come from a single, dramatic event

Bats depend on open bodies of water such as small ponds and lakes for foraging and drinking. Access to water is particularly important for survival in the increasingly hot and dry summers caused by climate change, the time when female bats are pregnant and rear their young. A scientific team has now shown that access to drinking sites is hampered by wind turbines in agricultural landscapes: Many bat species avoid the turbines and water bodies located close to the turbines for several kilometers.

The night sky has always played a crucial role in navigation, from early ocean crossings to modern GPS. Besides stars, the United States Navy uses quasars as beacons. Quasars are distant galaxies with supermassive black holes, surrounded by brilliantly hot disks of swirling gas that can blast off jets of material. Following up on the groundbreaking 2020 discovery of newborn jets in a number of quasars, aspiring naval officer Olivia Achenbach of the United States Naval Academy has used NASA's Hubble Space Telescope to reveal surprising properties of one of them, quasar J0742+2704.

The name 'blue lurker' might sound like a villainous character from a superhero movie. But it is a rare class of star that NASA's Hubble Space Telescope explored by looking deeply into the open star cluster M67, roughly 2,800 light-years away.

The Sun can kill. Until Earth developed its ozone layer hundreds of millions of years ago, life couldn’t venture out onto dry land for fear of exposure to the Sun’s deadly ultraviolet radiation. Even now, the 1% of its UV radiation that reaches the surface can cause cancer and even death.

Astronauts outside of Earth’s protective ozone layer and magnetic shield are exposed to far more radiation than on the planet’s surface. Exposure to radiation from the Sun and elsewhere in the cosmos is one of the main hurdles that must be cleared in long-duration space travel or missions to the lunar and Martian surfaces.

Unfortunately, there’s no harmonized approach to understanding the complexity of the hazard and protecting astronauts from it.

Astronauts haven’t gone further into space than the ISS for decades. But if Artemis lives up to its promise, they’re about to leave Earth and its protective environment behind. Artemis will land astronauts on the Moon, which could be an intermediate step to an eventual landing on Mars. What hazards does radiation pose, and how can astronauts be protected?

A new research editorial in the Journal of Medical Physics examines the issue. It is titled “System of radiological protection: Towards a consistent framework on Earth and in space.” The lead author is Werner Rühm from the Federal Office for Radiation Protection, München (Neuherberg), Germany. The same issue of the Journal of Medical Physics contains several other articles about radiation exposure. Together, they’re part of a research effort by the International Commission on Radiological Protection (ICRP) to update and harmonize radiation exposure guidelines.

The term ‘radiation’ is descriptive enough that most of us recognize the potential threat. However, when it comes to variable space environments and human physiology, the word holds a lot more detail. The authors use the term ‘mixed radiation field’ to describe the radiation environment astronauts must endure.

“The mixed-radiation field outside and within a space vehicle is of particular complexity involving not only low-linear energy transfer (LET) radiation such as gamma radiation, electrons, and positrons but also high-LET radiation such as neutrons and heavy ions,” the authors write. The components of the field contain a wide span of particles with different energy levels. “The quantitative and even qualitative risks of exposure to the combined impact of a complex radiation environment, microgravity, and other stressors remain unclear,” they explain.

One problem in preparing for exposure to these mixed radiation fields is the different approaches taken by different countries and space agencies.

NASA astronauts exploring Mars on future missions, perhaps starting in the 2030s, will require protection from long-term exposure to the cancer-causing space radiation environment. Credit: NASA.

According to lead author Rühm, this disharmony is caused by “the complex and dynamic radiation environments and an incomplete understanding of their biological consequences. Because of this, space agencies follow somewhat different concepts to quantify radiation doses and their resulting health effects.”

This paper and its companions are part of an effort to unify our understanding of radiation and its hazards and to harmonize the various approaches to dealing with them. The goal is to develop a “consistent radiological protection framework.” To do that, the authors explain that several questions need answers:

• Which radiation-induced health effects should be considered?
• What dose quantities are the best for the radiological protection of astronauts?
• Which metrics should be used to quantify radiation-related health risks?
• How do we address sex and age differences in radiation risk?
• What kind of protection criteria should be applied?
• How do we decide on the tolerability of radiation-induced risks, given that astronauts are exposed to many other occupation-related risks?
• How do we deal with the fact that increased health risks due to radiation exposure may persist after an astronaut’s career ends?
• How do we communicate radiation risk and make a comparison with other health hazards in a meaningful way?
• How do we harmonize national radiological protection guidelines, given that different subpopulations might have different levels of risk tolerance?

This list of questions vividly illustrates the complexity of the radiation exposure problem. Answering them will help harmonize the approach to radiation on space missions.

Rühm and his colleagues want to support space agencies as they harmonize and coordinate their guidelines for astronauts’ exposure to radiation. The goal is to develop an approach consistent with the thorough guidelines followed here on Earth.

The difference between how males and females respond to radiation illustrates one of the problems in developing radiation exposure guidelines. In past decades, much medical research was based on males and the results were applied to females as well. According to Rühm, the same thing has happened with radiation.

“It is worth mentioning that on Earth, the System developed by ICRP does not include any systematic differentiation between recommendations on limits for males and females,” the authors write. This is in spite of the fact that it is “well known that there are individual differences in radiation sensitivity between males and females.” The difference is largely because reproductive tissue is more susceptible to radiation than other tissue, and women have more of it.

This infographic shows how men’s and women’s bodies react differently to spaceflight. It’s also becoming well-known that women are more sensitive to radiation exposure. Image Credit: NASA/NSBRI

NASA has developed a different approach to radiation exposure because of this. “This standard is based on a REID (Risk of Exposure-Induced Death) of 3% calculated for cancer mortality in the most vulnerable group of astronauts––35-year-old females,” the authors write. Scientists understand that females are more vulnerable to radiation than males and that younger females are more sensitive than older females. It’s worth noting that astronauts are unlikely to be under the age of 35.

The difference between the sexes isn’t the only thing that needs to be addressed when it comes to astronauts’ exposure to radiation. Different sub-populations might have different risk factors; there are lifestyle-related risks, different mission architectures hold different risks, and many other factors come into play. Harmonizing an approach with all of these different factors is a daunting task.

Difficult or not—and there’s nothing easy about space travel—a harmonized and coordinated approach to understanding the radiation risk is the logical next step. Artemis itself is a collaboration between different nations and agencies, and it’s only fair to the astronauts themselves that they have the same protections and considerations when it comes to radiation exposure.

Rühm and his colleagues hope that their work will help lead to a harmonized approach to assessing the radiation hazards faced by astronauts in mixed radiation fields. We owe it to the people willing to put their lives on the line and serve as astronauts.

“Adventurous people have always tried to widen their horizon, this is part of our very nature as humans,” Rühm says. “Our work contributes to and supports one of the most exciting and challenging human endeavors ever undertaken.”

The post As We Explore the Solar System, Radiation Will Be One of Our Greatest Threats appeared first on Universe Today.

The tattoos of 1200-year-old mummies from Peru can now be seen in exquisite detail, showing fine markings that may have been made with cactus needles or animal bones

In February 2016, scientists working for the Laser Interferometer Gravitational-Wave Observatory (LIGO) made history by announcing the first-ever detection of gravitational waves (GW). These waves, predicted by Einstein’s Theory of General Relativity, are created when massive objects collide (neutron stars or black holes), causing ripples in spacetime that can be detected millions or billions of light years away. Since their discovery, astrophysicists have been finding applications for GW astronomy, which include probing the interiors of neutron stars.

For instance, scientists believe that probing the continuous gravitational wave (CW) emissions from neutron stars will reveal data on their internal structure and equation of state and can provide tests of General Relativity. In a recent study, members of the LIGO-Virgo-KAGRA (LVK) Collaboration conducted a search for CWs from 45 known pulsars. While their results showed no signs of CWs emanating from their sample of pulsars, their work does establish upper and lower limits on the signal amplitude, potentially aiding future searches.

The LVK Collaboration is an international consortium of scientists from hundreds of universities and institutes worldwide. This collaboration combines data from the Laser Interferometer Gravitational-Wave Observatory’s (LIGO) twin observatories, the Virgo Observatory, and the Kamioka Gravitational Wave Detector (KAGRA). The preprint of the paper, “Search for continuous gravitational waves from known pulsars in the first part of the fourth LIGO-Virgo-KAGRA observing run,” recently appeared online.

First discovered in 1967, pulsars are a class of neutron stars that have strong magnetic fields, causing them to emit beams of electromagnetic radiation from their poles. They also rotate rapidly, creating a strobing effect reminiscent of a lighthouse. Given their stability and predictability, pulsars present an opportunity to search for continuous gravitational waves (CWs). Unlike transient GW, which are produced by binary black hole and neutron star mergers, CWs are long-lasting signals expected to come from massive, spinning objects (like pulsars).

To date, all GW events observed by astronomers have been transient in nature. To find evidence of these events, the team searched for signals from 45 known pulsars (and a narrowband search for 16 pulsars) from the first part of the fourth LIGO-Virgo-KAGRA observing run (O4a). They also employed three independent data analysis methods and two different emission models. As they indicated in their paper, no CW signals were detected, but the results were still informative:

“No evidence of a CW signal was found for any of the targets. The upper limit results show that 29 targets surpass the theoretical spin-down limit. For 11 of the 45 pulsars not analyzed in the last LVK targeted search, we have a notable improvement in detection sensitivity compared to previous searches. For these targets, we surpass or equal the theoretical spin-down limit for the single-harmonic emission model. We also have, on average, an improvement in the upper limits for the low-frequency component of the dual-harmonic search for all analyzed pulsars.”

The team also conducted a search for polarization that is consistent with a theory of gravitation alternative to General Relativity (Brans–Dicke theory). While CWs remain unconfirmed, the team predicts that a full analysis of the full O4 dataset will improve the sensitivity of targeted/narrowband searches for pulsars and CWs.

Further Reading: arXiv

The post LIGO Fails to Find Continuous Gravitational Waves From Pulsars appeared first on Universe Today.

A new analysis of marsquakes measured by NASA’s InSight lander indicates Mars has a solid inner core – but other researchers say the evidence is thin

Scientists have succeeded in controlling the structure and function of biological membranes with the help of 'DNA origami'. The system they developed may facilitate the transportation of large therapeutic loads into cells. This opens up a new way for the targeted administration of medication and other therapeutic interventions. Thus, a very valuable instrument can be added to the toolbox of synthetic biology.

In a significant step toward creating a sustainable and circular economy, researchers have demonstrated that carbon nanotube (CNT) fibers can be fully recycled without any loss in their structure or properties. This discovery positions CNT fibers as a sustainable alternative to traditional materials like metals, polymers and the much larger carbon fibers, which are notoriously difficult to recycle.

A thorough analysis of market, technological, and supply chain outcomes for sodium-ion batteries finds that significant advances are needed before commercialization.

Scientists have come a step closer to understanding how collisionless shock waves -- found throughout the universe -- are able to accelerate particles to extreme speeds.

Scientists have taken a major step forwards in tackling one of the greatest abiding challenges in chemistry, by learning how to program the self-assembly of molecules in such a way that the end result is predictable and desirable. Their 'Malteser-like' molecules could one day have a suite of applications -- from highly sensitive and specific sensors, to next-gen, targeted drug delivery agents.