SPACE/COSMOS
New ESO image captures a dark wolf in the sky
ESO
image:
Fittingly nicknamed the Dark Wolf Nebula, this cosmic cloud was captured in a 283-million-pixel image by the VLT Survey Telescope (VST) at ESO’s Paranal Observatory in Chile. Located around 5300 light-years from Earth, the cold clouds of cosmic dust create the illusion of a wolf-like silhouette against a colourful backdrop of glowing gas clouds.
view moreCredit: ESO/VPHAS+ team
For Halloween, the European Southern Observatory (ESO) reveals this spooktacular image of a dark nebula that creates the illusion of a wolf-like silhouette against a colourful cosmic backdrop. Fittingly nicknamed the Dark Wolf Nebula, it was captured in a 283-million-pixel image by the VLT Survey Telescope (VST) at ESO’s Paranal Observatory in Chile.
Found in the constellation Scorpius, near the centre of the Milky Way on the sky, the Dark Wolf Nebula is located around 5300 light-years from Earth. This image takes up an area in the sky equivalent to four full Moons, but is actually part of an even larger nebula called Gum 55. If you look closely, the wolf could even be a werewolf, its hands ready to grab unsuspecting bystanders…
If you thought that darkness equals emptiness, think again. Dark nebulae are cold clouds of cosmic dust, so dense that they obscure the light of stars and other objects behind them. As their name suggests, they do not emit visible light, unlike other nebulae. Dust grains within them absorb visible light and only let through radiation at longer wavelengths, like infrared light. Astronomers study these clouds of frozen dust because they often contain new stars in the making.
Of course, tracing the wolf’s ghost-like presence in the sky is only possible because it contrasts with a bright background. This image shows in spectacular detail how the dark wolf stands out against the glowing star-forming clouds behind it. The colourful clouds are built up mostly of hydrogen gas and glow in reddish tones excited by the intense UV radiation from the newborn stars within them.
Some dark nebulae, like the Coalsack Nebula, can be seen with the naked eye –– and play a key role in how First Nations interpret the sky [1] –– but not the Dark Wolf. This image was created using data from the VLT Survey Telescope, which is owned by the National Institute for Astrophysics in Italy (INAF) and is hosted at ESO’s Paranal Observatory, in Chile’s Atacama Desert. The telescope is equipped with a specially designed camera to map the southern sky in visible light.
The picture was compiled from images taken at different times, each one with a filter letting in a different colour of light. They were all captured during the VST Photometric Hα Survey of the Southern Galactic Plane and Bulge (VPHAS+), which has studied some 500 million objects in our Milky Way. Surveys like this help scientists to better understand the life cycle of stars within our home galaxy, and the obtained data are made publicly available through the ESO science portal. Explore this treasure trove of data yourself: who knows what other eerie shapes you will uncover in the dark?
Notes
[1] The Mapuche people of south-central Chile refer to the Coalsack Nebula as ‘pozoko’ (water well), and the Incas called it ‘yutu’ (a partridge-like bird).
More information
The European Southern Observatory (ESO) enables scientists worldwide to discover the secrets of the Universe for the benefit of all. We design, build and operate world-class observatories on the ground — which astronomers use to tackle exciting questions and spread the fascination of astronomy — and promote international collaboration for astronomy. Established as an intergovernmental organisation in 1962, today ESO is supported by 16 Member States (Austria, Belgium, Czechia, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom), along with the host state of Chile and with Australia as a Strategic Partner. ESO’s headquarters and its visitor centre and planetarium, the ESO Supernova, are located close to Munich in Germany, while the Chilean Atacama Desert, a marvellous place with unique conditions to observe the sky, hosts our telescopes. ESO operates three observing sites: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its Very Large Telescope Interferometer, as well as survey telescopes such as VISTA. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world’s largest and most sensitive gamma-ray observatory. Together with international partners, ESO operates ALMA on Chajnantor, a facility that observes the skies in the millimetre and submillimetre range. At Cerro Armazones, near Paranal, we are building “the world’s biggest eye on the sky” — ESO’s Extremely Large Telescope. From our offices in Santiago, Chile we support our operations in the country and engage with Chilean partners and society.
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Ancient rocks may bring dark matter to light
With new imaging capabilities, the first successful dark-matter detector might be some old rock
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Ph.D. candidate Keegan Walkup (at left) and physicist Patrick Huber work in the new lab that Huber is establishing to look for evidence of dark matter inside the crystal lattice structures of old rocks.
view moreCredit: Photo by Spencer Coppage for Virginia Tech.
The visible universe — all the potatoes, gas giants, steamy romance novels, black holes, questionable tattoos, and overwritten sentences — accounts for only 5 percent of the cosmos.
A Virginia Tech-led team is hunting for the rest of it, not with telescopes or particle colliders, but by scrutinizing billion-year-old rocks for traces of dark matter.
In leading a transdisciplinary team from multiple universities on this unconventional search, physics’ Patrick Huber is also taking an unconventional step: from theoretical work into experimental work.
With support from a $3.5 million Growing Convergence Research award from the National Science Foundation and a separate $750,000 award from the National Nuclear Security Administration, Huber is building a new lab in Robeson Hall to test dark matter theories — and see what else might come to light along the way.
Dark matter is super dark
Scientists can only infer dark matter’s existence because objects in the universe fall faster than they should around the center of galaxies. Gravity from this unseen substance accounts for the extra oomph.
Unlike the bump and grind of regular stuff, dark matter is thought to interact only very weakly with other matter, imperceptible except when one happens to bump into a nucleus of a visible matter atom. Recoiling from the collision like an atomic billiard ball, the nucleus deposits a spark of energy.
Over the past 50 years, physicists have conducted all manner of dark-matter experiments in hopes of witnessing one of these rare recoil events.
So far? Dark matter has stayed dark. Physicists haven’t turned up any hard evidence for dark matter. Now they’re turning down — deep down.
Paleodetectives
If dark matter exists, there’s a chance it has interacted with the Earth at some point in its 4.6 billion-year-old history. What if, instead of waiting for dark matter to come to them, scientists could excavate ancient evidence from minerals deep in the Earth?
While the idea for using rocks as subterranean detectors was first proposed in the 1980s, technological advances prompted researchers, including Huber, to revisit this idea.
“It’s crazy. When I first heard about this idea, I was like — this is insane. I want to do it,” said Huber, the William E. Hassinger, Jr. Senior Faculty Fellow.
Huber, being a theoretical physicist, came up with a theory of how to solve it. But the theory wasn’t enough. If this plan was possible, he wanted to see what it would take to execute it.
“Other people in their midlife crisis might take a mistress or get a sports car. I got a lab,” Huber said.
Who knocked the nuclei?
By developing and using sophisticated imaging techniques, Huber and his collaborators hope to uncover miniature trails of destruction left by long-ago dark matter interactions inside crystal lattice structures.
When a high-energy particle bounces off a nucleus inside a rock, the explosive recoil can pop a nucleus out of place, said Vsevolod Ivanov, a researcher at the Virginia Tech National Security Institute who is collaborating with Huber. The ejected nucleus and the empty gap it leaves behind represent structural changes within crystal.
“We’ll take a crystal that’s been exposed to different particles for millions of years and subtract the distributions that correspond to things we do know,” Ivanov said. “Whatever is left must be something new, and that could be the dark matter.”
Most dark matter experiments are conducted underground to cut back on interference from other high-energy particles called cosmic rays, but going underground presents a new set of problems. The planet pulses with a radioactive background that can also jostle nuclei. University Distinguished Professor Robert Bodnar, recently inducted into the National Academy of Sciences, will be working with Huber’s team to identify, locate, and characterize minerals that could serve as suitable detectors.
Proof in 3D
To start in on this massive imaging task, Huber is working with researchers at the University of Zurich’s Brain Research Institute who provided access to special microbiology imaging technology typically used to image animal nervous systems.
The team has already started generating 3D renderings of high-energy particle tracks in synthetic lithium fluoride. This artificial crystal won’t make a good dark-matter detector, said Huber, but it will help establish the full range of signals while keeping the crystal intact. In an unexpected twist, applications of lithium fluoride imaging technology include “nuclear transparency devices,” which might look like backpack-sized monitoring devices for nuclear reactors.
With tangential outputs from this “insane” research objective already proving of immediate value, Huber his collaborators will dig deeper and look closer to see if an old rock can tell us how the stars fly around the galaxy.
NASA’s Hubble, Webb probe surprisingly smooth disk around Vega
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[left] A Hubble Space Telescope false-color view of a 100-billion-mile-wide disk of dust around the summer star Vega. Hubble detects reflected light from dust that is the size of smoke particles largely in a halo on the periphery of the disk. The disk is very smooth, with no evidence of embedded large planets. The black spot at the center blocks out the bright glow of the hot young star.
[right] The James Webb Space Telescope resolves the glow of warm dust in a disk halo, at 23 billion miles out. The outer disk (analogous to the solar system’s Kuiper Belt) extends from 7 billion miles to 15 billion miles. The inner disk extends from the inner edge of the outer disk down to close proximity to the star. There is a notable dip in surface brightness of the inner disk from approximately 3.7 to 7.2 billion miles. The black spot at the center is due to lack of data from saturation.
Credit: NASA, ESA, CSA, STScI, S. Wolff (University of Arizona), K. Su (University of Arizona), A. Gáspár (University of Arizona)
In the 1997 movie "Contact," adapted from Carl Sagan's 1985 novel, the lead character scientist Ellie Arroway (played by actor Jodi Foster) takes a space-alien-built wormhole ride to the star Vega. She emerges inside a snowstorm of debris encircling the star — but no obvious planets are visible.
It looks like the filmmakers got it right.
A team of astronomers at the University of Arizona, Tucson used NASA's Hubble and James Webb space telescopes for an unprecedented in-depth look at the nearly 100-billion-mile-diameter debris disk encircling Vega. "Between the Hubble and Webb telescopes, you get this very clear view of Vega. It's a mysterious system because it's unlike other circumstellar disks we've looked at," said Andras Gáspár of the University of Arizona, a member of the research team. "The Vega disk is smooth, ridiculously smooth."
The big surprise to the research team is that there is no obvious evidence for one or more large planets plowing through the face-on disk like snow tractors. "It's making us rethink the range and variety among exoplanet systems," said Kate Su of the University of Arizona, lead author of the paper presenting the Webb findings.
Webb sees the infrared glow from a disk of particles the size of sand swirling around the sizzling blue-white star that is 40 times brighter than our Sun. Hubble captures an outer halo of this disk, with particles no bigger than the consistency of smoke that are reflecting starlight.
The distribution of dust in the Vega debris disk is layered because the pressure of starlight pushes out the smaller grains faster than larger grains. "Different types of physics will locate different-sized particles at different locations," said Schuyler Wolff of the University of Arizona team, lead author of the paper presenting the Hubble findings. "The fact that we're seeing dust particle sizes sorted out can help us understand the underlying dynamics in circumstellar disks."
The Vega disk does have a subtle gap, around 60 AU (astronomical units) from the star (twice the distance of Neptune from the Sun), but otherwise is very smooth all the way in until it is lost in the glare of the star. This shows that there are no planets down at least to Neptune-mass circulating in large orbits, as in our solar system, say the researchers.
"We're seeing in detail how much variety there is among circumstellar disks, and how that variety is tied into the underlying planetary systems. We’re finding a lot out about the planetary systems — even when we can’t see what might be hidden planets," added Su. "There's still a lot of unknowns in the planet-formation process, and I think these new observations of Vega are going to help constrain models of planet formation."
Disk Diversity
Newly forming stars accrete material from a disk of dust and gas that is the flattened remnant of the cloud from which they are forming. In the mid-1990s Hubble found disks around many newly forming stars. The disks are likely sites of planet formation, migration, and sometimes destruction. Fully matured stars like Vega have dusty disks enriched by ongoing "bumper car" collisions among orbiting asteroids and debris from evaporating comets. These are primordial bodies that can survive up to the present 450-million-year age of Vega (our Sun is approximately ten times older than Vega). Dust within our solar system (seen as the Zodiacal light) is also replenished by minor bodies ejecting dust at a rate of about 10 tons per second. This dust is shoved around by planets. This provides a strategy for detecting planets around other stars without seeing them directly – just by witnessing the effects they have on the dust.
"Vega continues to be unusual," said Wolff. "The architecture of the Vega system is markedly different from our own solar system where giant planets like Jupiter and Saturn are keeping the dust from spreading the way it does with Vega."
For comparison, there is a nearby star, Fomalhaut, which is about the same distance, age and temperature as Vega. But Fomalhaut's circumstellar architecture is greatly different from Vega's. Fomalhaut has three nested debris belts.
Planets are suggested as shepherding bodies around Fomalhaut that gravitationally constrict the dust into rings, though no planets have been positively identified yet. "Given the physical similarity between the stars of Vega and Fomalhaut, why does Fomalhaut seem to have been able to form planets and Vega didn't?" said team member George Rieke of the University of Arizona, a member of the research team. "What's the difference? Did the circumstellar environment, or the star itself, create that difference? What's puzzling is that the same physics is at work in both," added Wolff.
First Clue to Possible Planetary Construction Yards
Located in the summer constellation Lyra, Vega is one of the brightest stars in the northern sky. Vega is legendary because it offered the first evidence for material orbiting a star — presumably the stuff for making planets — as potential abodes of life. This was first hypothesized by Immanuel Kant in 1775. But it took over 200 years before the first observational evidence was collected in 1984. A puzzling excess of infrared light from warm dust was detected by NASA's IRAS (Infrared Astronomy Satellite). It was interpreted as a shell or disk of dust extending twice the orbital radius of Pluto from the star.
In 2005, NASA's infrared Spitzer Space Telescope mapped out a ring of dust around Vega. This was further confirmed by observations using submillimeter telescopes including Caltech's Submillimeter Observatory on Mauna Kea, Hawaii, and also the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, and ESA's (European Space Agency's) Herschel Space Telescope, but none of these telescopes could see much detail. "The Hubble and Webb observations together provide so much more detail that they are telling us something completely new about the Vega system that nobody knew before," said Rieke.
Two papers (Wolff et al. and Su et. al.) from the Arizona team will be published in The Astrophysical Journal.
The James Webb Space Telescope is the world's premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).
The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, Colorado, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, Maryland, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
Explore More:
Finding Planetary Construction Zones
The science paper by Schuyler Wolff et al., PDF (3.24 MB)
The science paper by Kate Su et al., PDF (2.10 MB)
Media Contacts:
Claire Andreoli (claire.andreoli@nasa.gov), Laura Betz (laura.e.betz@nasa.gov)
NASA's Goddard Space Flight Center, Greenbelt, MD
Ray Villard, Christine Pulliam
Space Telescope Science Institute, Baltimore, MD
Journal
The Astrophysical Journal
Method of Research
Observational study
Subject of Research
Not applicable
Article Title
Deep Search for a scattered light dust halo around Vega with the Hubble Space Telescope, and Imaging of the Vega Debris System using JWST/MIRI
Mission to International Space Station launches research on brain organoids, heart muscle atrophy, and cold welding
The SpaceX CRS-31 mission to the ISS for NASA includes studies on in-space manufacturing, cardiac health, and a method to repair spacecraft damaged by debris
International Space Station U.S. National Laboratory
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The SpaceX Dragon spacecraft atop the Falcon 9 rocket at Kennedy Space Center in March 2023.
view moreCredit: SpaceX
KENNEDY SPACE CENTER (FL), November 1, 2024 – More than 25 payloads sponsored by the International Space Station (ISSInternational Space Station) National Laboratory, including technology demonstrations, in-space manufacturing, student experiments, and multiple projects funded by the U.S. National Science Foundation (NSF), are bound for the orbiting outpost. These investigations, launching on SpaceX’s 31st Commercial Resupply Services (CRS) mission for NASANational Aeronautics and Space Administration, aim to improve life on Earth through space-based research and foster a sustainable economy in low Earth orbit(Abbreviation: LEO) The orbit around the Earth that extends up to an altitude of 2,000 km (1,200 miles) from Earth’s surface. The International Space Station’s orbit is in LEO, at an altitude of approximately 250 miles. (LEO).
The mission is scheduled to launch no earlier than Monday, November 4 at 9:29 p.m. EST from Launch Complex 39A at NASA’s Kennedy Space Center. Below highlights some of the ISS National Lab-sponsored projects on this mission.
- Bristol Myers Squibb (BMS) will build on its legacy of protein crystallization on the space station with a project, in collaboration with ISS National Lab Commercial Service ProviderImplementation Partners that own and operate commercial facilities for the support of research on the ISS or are developing future facilities. Redwire Space, seeking to crystallize model small molecule compounds to support the manufacturing of more effective therapeutics. Crystals grown in microgravityThe condition of perceived weightlessness created when an object is in free fall, for example when an object is in orbital motion. Microgravity alters many observable phenomena within the physical and life sciences, allowing scientists to study things in ways not possible on Earth. The International Space Station provides access to a persistent microgravity environment. are often larger and more well-ordered than those grown on the ground and could have improved morphology (geometric shape).
- NSF is funding four investigations launching on this mission, including a collaborative project from Oregon State University and Texas Tech University focused on cardiac health. This experiment will use 3D-bioprinted cardiac organoids to study microgravity-induced heart muscle atrophy. Results could lead to an increased understanding of heart muscle atrophy, which occurs in several conditions, such as cancer, muscle disease, muscular dystrophy, diabetes, sepsis, and heart failure.
- Multiple projects sponsored by the ISS National Lab and funded by NASA focus on in-space manufacturing. One investigation by Sachi Bioworks, working with ISS National Lab Commercial Service Provider Space Tango, could help advance the development of new therapeutics for neurodegenerative conditions. The project will use brain organoids in microgravity to test the effects of a novel drug on Alzheimer’s disease, Parkinson’s disease, and dementia.
- The Malta College of Arts, Science, and Technology is launching a project, with support from ISS National Lab Commercial Service Provider Voyager Space, to test a heatless method of welding. Cold welding is a process that bonds similar metallic materials using force or pressure instead of heat. This method could one day be used to safely repair space platforms and ensure their long-term viability, which would help to address the growing concern of space debris. In this project, the research team will test remote-operated, cold welding to apply metal patches to simulated spacecraft hull samples.
- The Student Spaceflight Experiment Program (SSEP) will send 39 student-led experiments on its 18th mission to the space station. SSEP aims to prepare the next generation of scientists and engineers by actively involving school communities in the development of scientific investigations to be conducted in microgravity. More than 35 communities took part in this SSEP mission, engaging hundreds of students in grades 5-12, junior college, and undergraduate studies.
For additional information on ISS National Lab-sponsored investigations launching on NASA’s SpaceX CRS-31, visit our launch page. To learn more about the research and technology development sponsored by the ISS National Lab, including how to propose concepts for future space-based research, visit our website.
Download a high-resolution image for this release: SpaceX CRS-27 Prepares for Launch in March 2023
Faster space communication with record-sensitive receiver
Chalmers University of Technology
image:
In the new communication system from researchers at Chalmers University of Technology, in Sweden, a weak optical signal (red) from the spacecraft's transmitter can be amplified noise-free when it encounters two so-called pump waves (blue and green) of different frequencies in a receiver on Earth. Thanks to the researchers' noise-free amplifiers in the receiver, the signal is kept undisturbed and the reception on Earth becomes record-sensitive, which in turn paves the way for a more error-free and faster data transmission in space in the future.
view moreCredit: Chalmers University of Technology | Rasmus Larsson
In space exploration, long-distance optical links can now be used to transmit images, films and data from space probes to Earth using light. But in order for the signals to reach all the way and not be disturbed along the way, hypersensitive receivers and noise-free amplifiers are required. Now, researchers at Chalmers University of Technology, in Sweden, have created a system that, with a silent amplifier and record-sensitive receiver, paves the way for faster and improved space communication.
Space communication systems are increasingly based on optical laser beams rather than radio waves, as the signal loss has been shown to be less when light is used to carry information over very long distances. But even information carried by light loses its power during the journey, and optical systems for space communication therefore require extremely sensitive receivers capable of sensing signals that have been greatly weakened before they finally reach Earth. The Chalmers researchers' concept for optical space communication opens up new communication opportunities – and discoveries – in space.
"We can demonstrate a new system for optical communication with a receiver that is more sensitive than has been demonstrated previously at high data rates. This means that you can get a faster and more error-free transfer of information over very long distances, for example when you want to send high-resolution images or videos from the Moon or Mars to Earth," says Peter Andrekson, Professor of Photonics at Chalmers and one of the lead authors of the study, which was recently published in the scientific journal Optica.
Silent amplifier with simplified transmitter improves communication
The researchers' communication system uses an optical amplifier in the receiver that amplifies the signal with the least possible noise so that its information can be recycled. Just like the glow of a flashlight, the light from the transmitter widens and weakens with distance. Without amplification, the signal is so weak after the space flight that it is drowned out by the electronic noise of the receiver. After twenty years of struggling with disturbing noise that impaired the signals, the research team at Chalmers was able to demonstrate a noise-free optical amplifier a few years ago. But until now, the silent amplifier has not been able to be used practically in optical communication links, as it has placed completely new, significantly more complex, demands on both transmitter and receiver.
Due to the limited resources and minimal space on board a space probe, it is important that the transmitter is as simple as possible. By allowing the receiver on Earth to generate two of the three light frequencies needed for noise-free amplification, and at the same time allowing the transmitter to generate only one frequency, the Chalmers researchers were able to implement the noise-free amplifier in an optical communication system for the first time. The results show an outstanding sensitivity, while complexity at the transmitter is modest.
"This phase-sensitive optical amplifier does not, in principle, generate any extra noise, which contributes to a more sensitive receiver and that error-free data transmission is achieved even when the power of the signal is lower. By generating two extra waves of different frequencies in the receiver, rather than as previously done in the transmitter, a conventional laser transmitter with one wave can now be used to implement the amplifier. Our simplification of the transmitter means that already existing optical transmitters on board satellites and probes could be used together with the noise-free amplifier in a receiver on Earth," says Rasmus Larsson, Postdoctoral Researcher in Photonics at Chalmers and one of the lead authors of the study.
Can solve problematic bottleneck
The progress means that the researchers' silent amplifiers can eventually be used in practice in communication links between space and Earth. The system is thus poised to contribute in solving a well-known bottleneck problem among space agencies today.
NASA talks about 'the science return bottleneck', and here the speed of the collection of scientific data from space to Earth is a factor that constitutes an obstacle in the chain. We believe that our system is an important step forward towards a practical solution that can resolve this bottleneck," says Peter Andrekson.
The next step for the researchers is to test the optical communication system with the implemented amplifier during field studies on Earth, and later also in communication links between a satellite and Earth.
More about the scientific article
The study "Ultralow noise preamplified optical receiver using conventional single wavelength transmission" has been published in Optica and is written by Rasmus Larsson, Ruwan U Weerasuriya and Peter Andrekson. The researchers are active at Chalmers University of Technology and the University of Moratuwa, Sri Lanka.
The development of the technology has been done at Chalmers University of Technology and the research has been funded by the Swedish Research Council.
For more information, please contact:
Rasmus Larsson, Postdoctoral Researcher, Division of Photonics, Department of Microtechnology and Nanoscience, Chalmers University of Technology
rasmus.larsson@chalmers.se
Peter Andrekson, Professor, Division of Photonics, Department of Microtechnology and Nanoscience, Chalmers University of Technology
peter.andrekson@chalmers.se, +46 31 772 16 06
The contact persons both speak English and Swedish. They are available for live and pre-recorded interviews. At Chalmers, we have podcast studios and broadcast filming equipment on site and would be able to assist a request for a television, radio or podcast interview.
Illustration caption: In the new communication system from researchers at Chalmers University of Technology, in Sweden, a weak optical signal (red) from the spacecraft's transmitter can be amplified noise-free when it encounters two so-called pump waves (blue and green) of different frequencies in a receiver on Earth. Thanks to the researchers' noise-free amplifiers in the receiver, the signal is kept undisturbed and the reception on Earth becomes record-sensitive, which in turn paves the way for a more error-free and faster data transmission in space in the future.
Illustration credit: Chalmers University of Technology | Rasmus Larsson
Journal
Optica
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Ultralow-noise preamplified optical receiver using conventional single-wavelength transmission
The dynamic core of black holes
A new study investigates the internal dynamics of black holes and their implications for future astrophysical observations
Black holes continue to captivate scientists: they are purely gravitational objects, remarkably simple, yet capable of hiding mysteries that challenge our understanding of natural laws. Most observations thus far have focused on their external characteristics and surrounding environment, leaving their internal nature largely unexplored. A new study, conducted through a collaboration between the University of Southern Denmark, Charles University in Prague, Scuola Internazionale Superiore di Studi Avanzati (SISSA) in Trieste, and Victoria University of Wellington in New Zealand, and published in Physical Review Letters, examines a common aspect of the innermost region of various spacetime models describing black holes, suggesting that our understanding of these enigmatic objects may require further investigation.
According to the corresponding author, postdoc Raúl Carballo-Rubio from the research center CP3-Origins at the University of Southern Denmark, the key insight from this study is that “the internal dynamics of black holes, which remain largely uncharted, could radically transform our understanding of these objects, even from an external perspective.”
The Kerr solution to the equations of General Relativity is the most accurate representation of rotating black holes observed in gravitational astrophysics. It depicts a black hole as a maelstrom in spacetime, characterized by two horizons: an outer one, beyond which nothing can escape its gravitational pull, and an inner one that encloses a ring singularity, a region where spacetime as we know it ceases to exist. This model aligns well with observations, as deviations from Einstein's theory outside the black hole are regulated by new physics parameters, which govern the core's size and are expected to be quite small.
However, a recent study conducted by the international team mentioned above has highlighted a critical issue concerning the interior of these objects: while it was known that a static inner horizon is characterised by an infinite accumulation of energy, the study demonstrates that even more realistic dynamic black holes are subject to significant instability over relatively short timescales. This instability is due to an accumulation of energy that grows exponentially over time until it reaches a finite, but extremely large, value, capable of significantly influencing the overall geometry of the black hole and thus altering it.
The ultimate outcome of this dynamic process is still unclear, but the study implies that a black hole cannot stabilise in Kerr geometry, at least over long timescales, although the speed and magnitude of deviations from Kerr spacetime remain under investigation. As Stefano Liberati, professor at SISSA and one of the study's authors, explains: “This result suggests that the Kerr solution—contrary to previous assumptions—cannot accurately describe observed black holes, at least on the typical timescales of their existence.”
Understanding the role of this instability is therefore essential for refining theoretical models of the interior of black holes and their relationship to the overall structure of these objects. In this sense, it could provide a missing link between theoretical models and potential observations of physics beyond General Relativity. Ultimately, these results open new perspectives for studying black holes, offering an opportunity to deepen our understanding of their internal nature and dynamic behaviour.
Journal
Physical Review Letters
Article Title
Mass inflation without Cauchy horizons
Article Publication Date
1-Nov-202
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