Science

Copper-oxide (CuO2) superconductors, such as Bi2Sr2CaCu2O8+ (Bi2212), have unusually high critical temperatures. Optical reflectivity measurements of Bi2212 have shown that it exhibits strong optical anisotropy. However, this has not been studied through optical transmittance measurements, which can offer more direct insights into bulk properties. Now, researchers have elucidated the origin of this optical anisotropy through ultraviolet and visible light transmittance measurements of lead-doped Bi2212 single crystals, enabling a more precise investigation into its superconductivity mechanisms.

Copper-oxide (CuO2) superconductors, such as Bi2Sr2CaCu2O8+ (Bi2212), have unusually high critical temperatures. Optical reflectivity measurements of Bi2212 have shown that it exhibits strong optical anisotropy. However, this has not been studied through optical transmittance measurements, which can offer more direct insights into bulk properties. Now, researchers have elucidated the origin of this optical anisotropy through ultraviolet and visible light transmittance measurements of lead-doped Bi2212 single crystals, enabling a more precise investigation into its superconductivity mechanisms.

Ferrocene is a key molecule for developing molecular machines. However, it readily decomposes on the surface of flat noble metal substrates, marking a significant challenge. Now researchers have stabilized ferrocene by linking it with ammonium salts and trapping them in a molecular film made up of cyclic crown ether molecules. The ammonium-linked molecule performs reversible lateral sliding motion upon the application of electrical voltage, representing the smallest molecular machine.

A researcher has developed a new technique to detect long wave infrared (LWIR) photons of different wavelengths or 'colors.' The new detection and imaging technique will have applications in analyzing materials by their spectral properties, or spectroscopic imaging, as well as thermal imaging applications.

Non-reciprocal interactions can increase the order in an active system. The researchers created a model to describe the emerging patterns depending on the amount of non-reciprocity in an active system.

Researchers have developed a 3D-printed device that generates twisting light beams with orbital angular momentum (OAM), a form of rotational energy that can carry more data than regular beams.

Researchers have developed a 3D-printed device that generates twisting light beams with orbital angular momentum (OAM), a form of rotational energy that can carry more data than regular beams.

Researchers have successfully developed a deep learning model that classifies pancreatic ductal adenocarcinoma (PDAC), the most common form of pancreatic cancer, into molecular subtypes using histopathology images. This approach achieves high accuracy and offers a rapid, cost-effective alternative to current methods that rely on expensive molecular assays. The new study holds promise to advance personalized treatment strategies and improve patient outcomes.

Researchers have unlocked a new method for producing one class of 2D material and for supercharging its magnetic properties.

The future of breast cancer screening and risk-reducing strategies is being shaped by artificial intelligence (AI), according to a recent review article.

The future of breast cancer screening and risk-reducing strategies is being shaped by artificial intelligence (AI), according to a recent review article.

Theoretical physicists along with an experimental team have found evidence of a quantum spin liquid in a material known as pyrochlore cerium stannate. They achieved this by combining state-of-the-art experimental techniques, including neutron scattering at extremely low temperatures, with theoretical analysis. By measuring the way in which neutrons interact magnetically with the electron spin in pyrochlore, the researchers observed the collective excitations of spins interacting strongly with light-like waves.

The Earth and Moon have been locked in a gravitational dance for billions of years. Each day, as the Earth turns, the Moon tugs upon the oceans of the world, causing the rise and fall of tides. As a result, the Earth’s day gets a little bit longer, and the Moon gets a little more distant. The effect is small, but over geologic time it adds up. About 620 million years ago, a day on Earth was only 22 hours long, and the Moon was at least 10,000 km closer than it is now.

Evidence for this evolving dance in the geological record only goes back about two billion years. Beyond that, the Earth was so very different that there simply isn’t enough evidence to gather. So, instead, we must rely on computational models and our understanding of dynamics. We know that when the Earth formed, it had no large moon. Then, about 4.4 billion years ago, a Mars-sized protoplanet named Theia collided with our world to create the Earth-Moon system. What’s interesting is that most of the computer simulations for this collision generate a Moon that is much closer to the Earth than we’d expect. Early Earth didn’t have vast oceans, so there were no water tides to drive the Moon to a larger orbit. So how did the Moon get to its present distance?

The potential structure of a lava planet. Credit: Farhat, et al

A new study argues that back then the Earth did have tides, but they were made of lava, not water. Just after the Great Collision, Earth would have been covered in an ocean of hot lava. With the Moon so near, the lava would have experienced strong tides. Since lava is much denser than water, the effects of the tide would have been much greater. The Earth’s rotation would have slowed down much faster, and the Moon would quickly become more distant. Based on their simulations, the authors argue that the Moon’s distance would have increased by 25 Earth-radii in just 10,000 to 100,000 years. This would explain how the Moon moved towards its present distance range rather quickly.

The idea of tides on an ocean world also has implications for planets around other stars. Planets that form very close to their sun would be extremely hot, and many of them could have lava oceans for a billion years or more. Simulations of such worlds show that lava tides would accelerate the spin dynamics of such a world and could cause them to become tidally locked on a million-year timescale instead of a billion-year timescale. If this model is correct, it would have a significant impact on potentially habitable worlds. Most exoplanets orbit red dwarf stars, since red dwarfs make up about 75% of the stars in our galaxy. The habitable zone of red dwarfs is very close to the star, meaning that many of them would have begun as lava worlds. This would mean most potentially habitable worlds would have one side always facing the sun, while the other side is forever in the cold. Life on these worlds would be very different from what we see on Earth.

Reference: Farhat, Mohammad, et al. “Tides on Lava Worlds: Application to Close-in Exoplanets and the Early Earth-Moon System.” arXiv preprint arXiv:2412.07285 (2024).

The post Early Earth's Oceans of Magma Accelerated the Moon's Departure appeared first on Universe Today.

Wildlife photos return today, but I have precious few batches in the tank. If you got ’em, please send ’em, lest this feature disappear.

Today UC Davis mathematician Abby Thompson, who survived cancelation, is back with pictures of California tide pools. Abby’s captions are indented, and you can enlarge the photos by clicking on them.

November-December tidepools (Northern California).  The weather at the coast over the Thanksgiving weekend was spectacular- sunny, warm, with no wind; perfect for poking around in the tide pools.    As usual I got help with some of the IDs from people on inaturalist.

Mussel-covered rock (probably Mytilus californianus); I liked the pattern made on the sand as the tide retreated:

Calliostoma ligatum (blue-ringed top snail):

Eupentacta quinquesemita (stiff-footed sea cucumber) Probably; it’s a little hard to tell with sea cucumbers. This one was a couple of inches long.

Hemigrapsus nudus (Purple shore crab). This is one of the most common crabs on this stretch of shore.   This one was small (maybe 2” across the back) but testy, apparently ready to take me on:

Dendronotus subramosus (nudibranch). Nudibranchs are often scarce at this time of year, but the calm sea seems to have brought them out:

Phidiana hiltoni (nudibranch) Posing for the camera:

Anthopleura artemisia (moonglow anemone). I’ve posted a few pictures of this species.   The color varies so much that they all look quite different.   I’ve never seen one that’s blue before; it was striking next to the brilliant orange sponge:

Hermissenda opalescens: (nudibranch):

Cervus canadensis nannodes (Tule elk) from tiny creatures to large (although this species is small for elk). This picture is from Point Reyes National Seashore, where there’s a reserve.    A short, highly recommended hike takes you to where the elk can be found wandering about:

Tomales Point at sunset, as the tide was beginning to turn:

Camera info:  Mostly Olympus TG-7, in microscope mode, pictures taken from above the water.    The last two pictures were taken with my iphone.

La Niña conditions are expected to lead to a slightly cooler average global surface temperature in 2025, though it does not mean the planet as a whole has stopped warming

Currently, 5,788 exoplanets have been confirmed in 4,326 star systems, while thousands more candidates await confirmation. So far, the vast majority of these planets have been gas giants (3,826) or Super-Earths (1,735), while only 210 have been “Earth-like” – meaning rocky planets similar in size and mass to Earth. What’s more, the majority of these planets have been discovered orbiting within M-type (red dwarf) star systems, while only a few have been found orbiting Sun-like stars. Nevertheless, no Earth-like planets orbiting within a Sun-like star’s habitable zone (HZ) have been discovered so far.

This is largely due to the limitations of existing observatories, which have been unable to resolve Earth-sized planets with longer orbital periods (200 to 500 days). This is where next-generation instruments like the ESA’s PLAnetary Transits and Oscillations of stars (PLATO) mission come into play. This mission, scheduled to launch in 2026, will spend four years surveying up to one million stars for signs of planetary transits caused by rocky exoplanets. In a recent study, an international team of scientists considered what PLATO would likely see based on what it would see if observing the Solar System itself.

The study was led by Andreas F. Krenn, a PhD student at the Space Research Institute at the Austrian Academy of Sciences. He was joined by researchers from the Observatoire Astronomique de l’Université de Genève, Aix Marseille University, the Columbia Astrophysics Laboratory, the Leibniz Institute for Astrophysics Potsdam (AIP), the Institute of Astronomy at KU Leuven, the National Center for Atmospheric Research, and the Kanzelhöhe Observatory for Solar and Environmental Research at the University of Graz. The paper that describes their research recently appeared in the journal Astronomy & Astrophysics.

As they note in their study, an Earth-like planet orbiting within the HZ of a G-type star would be a prime target to search for biosignatures. These include oxygen gas, carbon dioxide, methane, ammonia, and water vapor in the atmosphere, as well as indications of photosynthesis taking place on the surface – i.e., the vegetation red edge (VRE). This has been very difficult for telescopes as Earth-like planets are more likely to orbit closer to Sun-like stars, making it difficult to obtain data on their atmospheres using either Direct Imaging or transmission spectra.

This latter technique involves the Transit Photometry (or the Transit Method), where astronomers measure the light curve of distant stars for periodic dips in brightness. These are often the result of exoplanets passing in front of the star (i.e., transiting) relative to the observer. To date, the vast majority of exoplanets – more than 4,300, or 74.5% – have been confirmed using this method. When the conditions are right, astronomers sometimes observe light as it passes through the exoplanet’s atmosphere, which is then studied using spectrometers to determine its chemical composition.

But as Krenn told Universe Today via email, this has been a significant challenge for astronomers:

“The main difficulty is the small signals that such planets generate. For example, the radial velocity amplitude of the Earth is roughly 0.1 m/s. This is about the speed of a giant Galapagos tortoise. That means that if a distant observer would like to see the Sun’s motion around the common center of mass of the Earth-Sun system, they would need to see the Sun move at the speed of a giant Galapagos tortoise from light years away.

“Similarly, the relative amount emitted by the Sun that is blocked by the Earth when a distant observer observes the Earth transiting across the solar disk is 84 parts per million, which is 0.0084%. So a distant observer would need to see the light of that star being dimmed by 0.0084% in order to detect Earth.”

Moreover, Krenn added that existing spectrographs have not been precise enough to measure such small signals. Whereas exoplanet-hunting missions like the ESA’s CHaracterising ExOPlanets Satellite (CHEOPS) have managed to obtain spectra from transiting exoplanets, several transit events were needed to achieve this precision. This isn’t easy when dealing with planets like Earth with longer orbital periods that fit into the 200- to 500-day range. Lastly, instrumental effects and stellar variability can be orders of magnitude larger than a planetary signal.

This is expected to change considerably with the ESA’s next-generation PLAnetary Transits and Oscillations of stars (PLATO) space telescope. This mission will rely on a multi-telescope approach involving 26 cameras, including 24 “normal” cameras organized in 4 groups and 2 “fast” cameras for bright stars. These instruments will continuously observe the same area of the sky for at least two years to detect transit signals by Earth-like planets around solar analogs. Said Krenn:

“PLATO’s photometric instrument will be precise enough to detect the transit of an Earth-like planet orbiting a solar-like star using a single transit event. Supported by its stellar variability program and ground-based follow-up campaign, we will hopefully be able to correctly account for the influences of noise sources. In short, PLATO will utilize the interdisciplinary of exoplanet science on a whole new level. It will combine high-precision photometry, up-to-date data analysis tools, a dedicated stellar variability program, and its own ground-based follow-up campaign.

“Experts from all of these fields will work together to try and make the detection of these tiny planetary signals possible. Additionally, PLATO will also utilize a special observing strategy that allows it to observe thousands of stars a the same time and produce 2 years of almost continuous photometric data for each of them.”

ESA’s trifecta of dedicated exoplanet missions – Cheops, Plato, and Ariel – will also be complemented by the James Webb Space Telescope mission Credit: ESA

To assess what PLATO might see when observing thousands of Sun-like stars for Earth analogs, the team modeled the impact of short-term solar variability using the Sun as a proxy. This consisted of using data obtained by the Helioseismic and Magnetic Imager (HMI) aboard NASA’s Solar Dynamics Observatory, which has been observing the Sun continuously since 2010. Using 88 consecutive days of HMI observations, they injected Earth-like transit signals and noise models into the data and simulated PLATO observations for five scenarios and five stellar magnitudes.

Their results showed that transit signals can be reliability detected with a high signal-to-noise ratio for bright targets, but still very likely for faint ones. They further found that the PLATO mission has a good shot at precisely and accurately measuring the size of Earth-like planets, one of its chief objectives. As Krenn explained, these findings could help inform the PLATO mission and assist in finding the signals of Earth analogs amid all the noise, though much work needs to be done to ensure all sources of noise are accounted for:

“In our analysis, we focused only on the effects of short-term variability, which we know is only one of many noise sources that will affect PLATO observations. We have seen that even correctly accounting for this single type of noise can be challenging. The final analysis of PLATO data will need to combine a variety of complex noise models simultaneously to correctly account for all of the different noise sources. I think our research has shown that we need to have an in-depth understanding of individual noise sources but, at the same time, also need to learn how to best combine all of the individual models.”

Other next-generation instruments, such as the James Webb Space Telescope (JWST), the Atmospheric Remote-sensing Infrared Exoplanet Large-survey (ARIEL) telescope, and the Nancy Grace Roman Space Telescope will also allow for the discovery and characterization of countless exoplanets using the Direct Imaging Method. Along with upcoming ground-based observatories, these missions will rely on advanced optics, coronographs, and spectrometers to locate more Earth analogs and analyze their atmospheres and surfaces for evidence of life. Soon enough, astronomers will do away with terms like “potentially habitable” and be able to say with confidence that an exoplanet is “habitable” (and perhaps even “inhabited”!)

Further Reading: Astronomy & Astrophysics

The post Could the ESA’s PLATO Mission Find Earth 2.0? appeared first on Universe Today.

Most galaxies are thought to play host to black holes. At the center of Centaurus A, a galaxy 12 million light years away, a jet is being fired out into space. Images that have been captured by NASA’s Chandra X-ray observatory show that the high energy particles have struck a nearby object creating a shockwave. The target is thought to be a giant star, maybe even a binary system, where the collision and turbulence has increased density in the region.

A black hole is an object and a region of space! At the centre is the singularity, a single point object where density is infinite and all the laws of physics seem to fail us. Surrounding the singularity is a region of space where the velocity needed to escape the singularity’s gravitational pull is in excess of the speed of light. The boundary between the region of space dominated by the singularity and dare I say ‘normal space’ is known as the event horizon. Collectively we call this phenomenon a black hole. 

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

Black holes at the centre of galaxies are usually supermassive, often millions to billions of times more massive than the Sun. They exert an immense pull of gravity which has an impact on the motion of stars and gas within their host galaxy. Matter getting drawn toward a black hole by its immense gravitational pull forms into an accretion disk surrounding the black hole. Here the gravitational force is high and so it heats the incoming material. The material falling in to the black hole gets heated to extreme temperatures generating strong electromagnetic fields. The fields can accelerate the particles outward forming into the familiar jet structure. 

A simulation of a galaxy’s ‘heart and lungs’ at work is pictured inset on an artist’s impression of bi-polar jets of gas originating from a supermassive black hole at the centre of a galaxy. Credit ESA/Hubble, L. Calçada (ESO) / C Richards/MD Smith/University of Kent Licence type Attribution (CC BY 4.0)

Our own Milky Way galaxy has a black hole at the centre as does the galaxy Centaurus A. At a distance of 12 million light years, it’s relatively in our back yard! A team of astronomers have turned NASA’s Chandra X-Ray observatory on Centaurus A and found the jet of its black hole striking an unidentified object. The team of astronomers discovered that parts of the jet are moving at speeds close to the speed of light. They also detected the region where it seemed to be striking something, appearing as a bright source of X-rays in the image, known as C4. 

This is Centaurus A, the nearest galaxy with an active nucleus. The active nucleus is where a supermassive black hole resides. One of the questions in astrophysics is how SMBHs grow so large, and the JWST should help answer that question. Image Credit: By ESO/WFI (Optical); MPIfR/ESO/APEX/A.Weiss et al. (Submillimetre); NASA/CXC/CfA/R.Kraft et al. (X-ray)

At a distance of 12 million light years, it’s too far away for the object to be seen but the team theorise that it’s either a massive star or one with a companion star. It’s thought that the X-rays are caused by a collision between the particles in the jet and the stellar wind from the star. The impact from the collision can be the generation of turbulence which leads to an increase in the density of gas in the jet, driving the X-ray emissions that have been detected. 

In the deepest image from Chandra, at the C4 source there appeared a strange V-shaped structure. The shape is not fully understood but analysis revealed the arms of the ‘V’ are at least 700 light years long! The results were published in the Astrophysical Journal by lead author David Bogensberger from the University of Michigan and a team of US astronomers. 

Source : Black Hole Jet Stumbles Into Something in the Dark

The post Zap! A Black Hole Scores a Direct Hit With its Jet appeared first on Universe Today.

More and more people under 50 have been diagnosed with bowel cancer in different parts of the world over the past few decades

On 24 December, the Parker Solar Probe will be the closest human-made object ever to a star, taking unprecedented measurements of the sun

Just a few months after the previous record was set, a start-up called Quantinuum has announced that it has entangled the largest number of logical qubits – this will be key to quantum computers that can correct their own errors