COMPUTER MODELS OF INJURED BRAINS PREDICT NEUROLOGICAL DEFICITS IN STROKE
The fundamental mechanisms underlying the dynamics of brain activity are still largely unknown. Their knowledge could help understand the brain‘s response to pathological conditions, such as brain injury (strokes). Despite the efforts of the scientific community, the neural mechanisms underlying the functional and behavioral recovery of stroke patients are still poorly understood.
The study ‘Recovery of neural dynamics criticality in personalized whole brain models of stroke‘ published in Nature Communications, fruit of an international collaboration between physicists, neurologists, and psychologists, by Rodrigo Rocha, Loren Koçillari, Samir Suweis, Michele De Grazia, Michel Thiebaut De Schotten, Marco Zorzi and Maurizio Corbetta, proposes the theory of brain criticality to explain brain-behaviour relationships in neurological patients.
Interdisciplinary research in neuroscience, inspired by statistical physics, has suggested that healthy brain’s neural dynamics operate at a critical state (i.e., in the vicinity of a critical phase transition between order and disorder) that provides optimal functional capabilities. If criticality is indeed a fundamental property of healthy brains, then neurological dysfunctions shall alter this optimal dynamical configuration. Some studies have reported disrupted criticality during epileptic seizures, slow-wave sleep, anesthesia, and Alzheimer’s disease. However, a crucial test of the hypothesis requires showing alterations of criticality after focal brain injury that cause local alterations of the brain’s structural and functional architecture. Furthermore, these alterations shall improve over time in parallel to recovery. Another prediction is that if criticality is essential for behaviour, then its alteration after focal injury shall relate to behavioural dysfunction and recovery of function. Finally, changes in criticality should also correlate with plasticity mechanisms that underlie recovery.
“The aim of the present work was to address these important questions through an interdisciplinary approach combining neuroimaging, computational neuroscience, statistical physics, and data science methods“, explain Rodrigo Rocha (Department of Physics of the Federal University of Santa Catarina, Florianópolis, Brazil). “We examined how brain lesions change criticality using a novel personalized whole brain modelling approach. Our theoretical framework models individual (i.e., single patient) brain dynamics based on real structural connectivity networks. We studied longitudinally a cohort of first-time stroke and healthy participants with neuropsychological tests, and diffusion weighted imaging (DWI) and functional MRI (fMRI) connectivity measures. We found that patients affected by stroke present at three months decreased levels of neural activity, decreased entropy, and decreased strength of functional connections. All these factors contribute to an overall loss of criticality that improves over time with recovery. We also show that changes in criticality predict the degree of behavioural recovery and critically depend on specific white matter connections. In summary, our work describes an important advance in understanding the alteration of brain dynamics as well as brain-behaviour relationships in neurological patients” says Rodrigo Rocha.
Rodrigo Rocha
“Our results show that personalized whole brain computer models can be used to track and predict stroke recovery at the level of single patients, thereby opening promising paths for novel interventions as computer models will allow to test the efficacy of different strategies to improve function” concludes Maurizio Corbetta (Department of Neuroscience and Padova Neuroscience, University of Padua, and Venetian Institute of Molecular Medicine).
Maurizio Corbetta
R.P.R. was funded by Research, Innovation and Dissemination Center for Neuromathematics (FAPESP) and the National Council for Scientific and Technological Development (CNPq), Brasil, to RR; M.T.dS by European Research Council (ERC) H2020 (grant# 818521); M.D.F. and M.Z. the Italian Ministry of Health (Grant# RF-2013-02359306); M.C. by the Italian Ministry of Research Departments of Excellence (2017-2022), CARIPARO foundation (Grant #55403), Italian Ministry of Health (Grant# RF-2018-12366899; RF-2019-12369300), H2020-SC5-2019-2 (Grant # 869505); H2020-SC5-2019-2 (Grant # 869505).
Info sheet
Who: Department of Physics of the Federal University of Santa Catarina; Laboratory of Neural Computation Istituto Italiano di Tecnologia (Rovereto); Department of Physics and Astronomy of the University of Padua; Brain Connectivity and Behaviour Laboratory of the Sorbonne Universities; Groupe d’imagerie Neurofonctionnelle of the University of Bordeaux; Department of General Psychology of the University of Padua; IRCCS San Camillo Hospital Venice; Department of Neuroscience and Padova Neuroscience Center (PNC), of the University of Padua; and, Veneto Institute of Molecular Medicine (VIMM)
What: Interdisciplinary approach to study the role of brain criticality and brain-behavior relationships in neurological patients published in Nature Communications: Recovery of neural dynamics criticality in personalized whole brain models of stroke.
Computer models of injured brains predict neurological deficits in stroke. Picture by Gerd Altmann
New research questions hypotheses about climate-controlled ecosystem change during the origin of dinosaurs in Argentina
A group of researchers from CONICET and the University of Utah demonstrated that during the time of the first dinosaurs, variations in the diversity and abundance of the plant and vertebrate animal species cannot be related to the climatic changes recorded throughout its deposition, in contrast with previous hypotheses.
Artist’s reconstruction of the Triassic ecosystem preserved in the Ischigualasto Formation. Animals include amphibians (bottom center-left underwater), rhynchosaurian reptiles (left mid-ground on riverbank), early crocodilian relatives (far left mid-ground and center far background), early mammal relatives (center mid-ground in river and along riverbank, and far right foreground), and early dinosaurs (far left foreground, center right foreground, and far right mid-ground). Credits: Jorge Gonzalez/Natural History Museum of Utah
In the new study, published in the open access journal Frontiers in Earth Science, the team of scientists investigated multiple independent lines of evidence (sedimentology, clay mineralogy, and geochemistry) to elucidate changes paleoclimatic conditions (such as mean annual precipitation and mean annual temperature) within the Ischigualasto Formation. These fossil-rich sedimentary rocks were deposited by rivers and streams between ~231 and 226 million years ago during the Late Triassic Period in what is now northwestern Argentina (La Rioja and San Juan provinces). In the middle of the formation, the researchers observed a clear change in conditions approximately from warmer, drier conditions to more temperate humid conditions, but no concurrent major changes could be identified in the fossil record.
An overview of extensive Ischigulasto Formation outcrops in the study area, located in La Rioja Province, northwestern Argentina. Credits: Randall Irmis/Natural History Museum of Utah
“We conclude that variations in the abundance and diversity of species, as recorded by their first and last appearances in the fossil record, are better explained by preservation and sampling biases biases than by changes in climate,” said Adriana Mancuso, lead author and CONICET independent researcher at the Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales in Mendoza, Argentina.
“What we see is that how many specimens collected from each interval of the sequence, and the chemical & physical characteristics that allow greater or lesser preservation of the remains of animals and plants, were significant factors. These two factors, collection and preservation, have more influence on the increase or decrease of abundance and diversity than the climate changes recorded,” explained Mancuso.
However, although the evolution of the ecosystem does not generally show a biotic response associated with climate change, the research group did observe a relationship between climatic variations and two groups of reptiles, rhynchosaurs (herbivorous early archosauromorphs) and pseudosuchians (crocodilian-line archosaurs).
“We did find that the abundance of rhynchosaurs and extinction of a few pseudosuchian species appear to coincide with a climate shift,” said Randall Irmis, co-author from the U and the Natural History Museum of Utah.
New research questions hypotheses about climate-controlled ecosystem change during the origin of dinosaurs in Argentina: a team member exposes fresh rock to obtain a geologic sample for geochemical lab analysis to reconstruct the paleoclimate record of the Ischigualasto Formation. Credits: Adriana Mancuso
Beyond conclusions about this specific fossil and paleoclimate record from Argentina, the new research emphasizes the importance of an explicit framework for testing hypotheses about the link between climatic changes and the fossil record.
“In addition to the contribution on the relationship of biotic and climatic events in the Ischigualasto Formation, the work provides a methodological framework to test climate-biota associations, highlighting the data gaps that must be filled, and makes new testable predictions that can be tested in future studies,” concludes Mancuso.
Other authors include Tomás Pedernera and Cecilia Benavente of the Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales (CONICET), Leandro Gaetano from the Instituto de Estudios Andinos (CONICET) and Departamento de Ciencias Geológicas of the Universidad de Buenos Aires, and Benjamin Breeden of the University of Utah.
Bibliographical information:
Paleoenvironmental and biotic changes in the Late Triassic of Argentina: testing hypotheses of abiotic forcing at the basin scale, Frontiers in Earth Science (13-Jun-2022), DOI: 10.3389/feart.2022.883788
Astronomers reveal first image of the black hole at the heart of our galaxy
Today, at simultaneous press conferences around the world, including at the European Southern Observatory (ESO) headquarters in Germany, astronomers have unveiled the first image of the supermassive black hole at the centre of our own Milky Way galaxy. This result provides overwhelming evidence that the object is indeed a black hole and yields valuable clues about the workings of such giants, which are thought to reside at the centre of most galaxies. The image was produced by a global research team called the Event Horizon Telescope (EHT) Collaboration, using observations from a worldwide network of radio telescopes.
The black hole at the heart of our galaxy. This artist’s impression depicts a rapidly spinning supermassive black hole surrounded by an accretion disc. This thin disc of rotating material consists of the leftovers of a Sun-like star which was ripped apart by the tidal forces of the black hole. The black hole is labelled, showing the anatomy of this fascinating object. Credit:ESOThe black hole at the heart of our galaxy. This chart shows the location of the field of view within which Sagittarius A* resides — the black hole is marked with a red circle within the constellation of Sagittarius (The Archer). This map shows most of the stars visible to the unaided eye under good conditions. Credit:ESO, IAU and Sky & Telescope
The image is a long-anticipated look at the massive object that sits at the very centre of our galaxy. Scientists had previously seen stars orbiting around something invisible, compact, and very massive at the centre of the Milky Way. This strongly suggested that this object — known as Sagittarius A* (Sgr A*, pronounced “sadge-ay-star”) — is a black hole, and today’s image provides the first direct visual evidence of it.
The black hole at the heart of our galaxy. This is the first image of Sgr A*, the supermassive black hole at the centre of our galaxy. It’s the first direct visual evidence of the presence of this black hole. It was captured by the Event Horizon Telescope (EHT), an array which linked together eight existing radio observatories across the planet to form a single “Earth-sized” virtual telescope. The telescope is named after the event horizon, the boundary of the black hole beyond which no light can escape. Although we cannot see the event horizon itself, because it cannot emit light, glowing gas orbiting around the black hole reveals a telltale signature: a dark central region (called a shadow) surrounded by a bright ring-like structure. The new view captures light bent by the powerful gravity of the black hole, which is four million times more massive than our Sun. The image of the Sgr A* black hole is an average of the different images the EHT Collaboration has extracted from its 2017 observations. In addition to other facilities, the EHT network of radio observatories that made this image possible includes the Atacama Large Millimeter/submillimeter Array (ALMA) and the Atacama Pathfinder EXperiment (APEX) in the Atacama Desert in Chile, co-owned and co-operated by ESO is a partner on behalf of its member states in Europe. Credit: EHT Collaboration
Although we cannot see the black hole itself, because it is completely dark, glowing gas around it reveals a telltale signature: a dark central region (called a shadow) surrounded by a bright ring-like structure. The new view captures light bent by the powerful gravity of the black hole, which is four million times more massive than our Sun.
“We were stunned by how well the size of the ring agreed with predictions from Einstein’s Theory of General Relativity,” said EHT Project Scientist Geoffrey Bower from the Institute of Astronomy and Astrophysics, Academia Sinica, Taipei. “These unprecedented observations have greatly improved our understanding of what happens at the very centre of our galaxy, and offer new insights on how these giant black holes interact with their surroundings.” The EHT team’s results are being published today in a special issue of The Astrophysical Journal Letters.
Because the black hole is about 27 000 light-years away from Earth, it appears to us to have about the same size in the sky as a doughnut on the Moon. To image it, the team created the powerful EHT, which linked together eight existing radio observatories across the planet to form a single “Earth-sized” virtual telescope [1]. The EHT observed Sgr A* on multiple nights in 2017, collecting data for many hours in a row, similar to using a long exposure time on a camera.
The black hole at the heart of our galaxy. The Event Horizon Telescope (EHT) Collaboration has created a single image (top frame) of the supermassive black hole at the centre of our galaxy, called Sagittarius A*, or Sgr A* for short, by combining images extracted from the EHT observations. The main image was produced by averaging together thousands of images created using different computational methods — all of which accurately fit the EHT data. This averaged image retains features more commonly seen in the varied images, and suppresses features that appear infrequently. The images can also be clustered into four groups based on similar features. An averaged, representative image for each of the four clusters is shown in the bottom row. Three of the clusters show a ring structure but, with differently distributed brightness around the ring. The fourth cluster contains images that also fit the data but do not appear ring-like. The bar graphs show the relative number of images belonging to each cluster. Thousands of images fell into each of the first three clusters, while the fourth and smallest cluster contains only hundreds of images. The heights of the bars indicate the relative “weights,” or contributions, of each cluster to the averaged image at top. In addition to other facilities, the EHT network of radio observatories that made this image possible includes the Atacama Large Millimeter/submillimeter Array (ALMA) and the Atacama Pathfinder EXperiment (APEX) in the Atacama Desert in Chile, co-owned and co-operated by ESO is a partner on behalf of its member states in Europe. Credit: EHT Collaboration
In addition to other facilities, the EHT network of radio observatories includes the Atacama Large Millimeter/submillimeter Array (ALMA) and the Atacama Pathfinder EXperiment (APEX) in the Atacama Desert in Chile, co-owned and co-operated by ESO on behalf of its member states in Europe. Europe also contributes to the EHT observations with other radio observatories — the IRAM 30-meter telescope in Spain and, since 2018, the NOrthern Extended Millimeter Array (NOEMA) in France — as well as a supercomputer to combine EHT data hosted by the Max Planck Institute for Radio Astronomy in Germany. Moreover, Europe contributed with funding to the EHT consortium project through grants by the European Research Council and by the Max Planck Society in Germany.
This image shows the Atacama Large Millimeter/submillimeter Array (ALMA) looking up at the Milky Way as well as the location of Sagittarius A*, the supermassive black hole at our galactic centre. Highlighted in the box is the image of Sagittarius A* taken by the Event Horizon Telescope (EHT) Collaboration. Located in the Atacama Desert in Chile, ALMA is the most sensitive of all the observatories in the EHT array, and ESO is a co-owner of ALMA on behalf of its European Member States. Credit: ESO/José Francisco Salgado (josefrancisco.org), EHT Collaboration
“It is very exciting for ESO to have been playing such an important role in unravelling the mysteries of black holes, and of Sgr A* in particular, over so many years,” commented ESO Director General Xavier Barcons. “ESO not only contributed to the EHT observations through the ALMA and APEX facilities but also enabled, with its other observatories in Chile, some of the previous breakthrough observations of the Galactic centre.” [2]
The EHT achievement follows the collaboration’s 2019 release of the first image of a black hole, called M87*, at the centre of the more distant Messier 87 galaxy.
These panels show the first two images ever taken of black holes. On the left is M87*, the supermassive black hole at the centre of the galaxy Messier 87 (M87), 55 million light-years away. On the right is Sagittarius A* (Sgr A*), the black hole at the centre of our Milky Way. The two images show the black holes as they would appear in the sky, with their bright rings appearing to be roughly the same size, despite M87* being around a thousand times larger than Sgr A*. The images were captured by the Event Horizon Telescope (EHT), a global network of radio telescopes including the Atacama Large Millimeter/submillimeter Array (ALMA) and Atacama Pathfinder EXperiment (APEX), in which ESO is co-owner. Credit: EHT Collaboration
The two black holes look remarkably similar, even though our galaxy’s black hole is more than a thousand times smaller and less massive than M87* [3].
“We have two completely different types of galaxies and two very different black hole masses, but close to the edge of these black holes they look amazingly similar,” says Sera Markoff, Co-Chair of the EHT Science Council and a professor of theoretical astrophysics at the University of Amsterdam, the Netherlands.
“This tells us that General Relativity governs these objects up close, and any differences we see further away must be due to differences in the material that surrounds the black holes.”
Size comparison of the two black holes imaged by the Event Horizon Telescope (EHT) Collaboration: M87*, at the heart of the galaxy Messier 87, and Sagittarius A* (Sgr A*), at the centre of the Milky Way. The image shows the scale of Sgr A* in comparison with both M87* and other elements of the Solar System such as the orbits of Pluto and Mercury. Also displayed is the Sun’s diameter and the current location of the Voyager 1 space probe, the furthest spacecraft from Earth. M87*, which lies 55 million light-years away, is one of the largest black holes known. While Sgr A*, 27 000 light-years away, has a mass roughly four million times the Sun’s mass, M87* is more than 1000 times more massive. Because of their relative distances from Earth, both black holes appear the same size in the sky. Credit: EHT collaboration (acknowledgment: Lia Medeiros, xkcd)
This achievement was considerably more difficult than for M87*, even though Sgr A* is much closer to us. EHT scientist Chi-kwan (‘CK’) Chan, from Steward Observatory and Department of Astronomy and the Data Science Institute of the University of Arizona, USA, explains:
“The gas in the vicinity of the black holes moves at the same speed — nearly as fast as light — around both Sgr A* and M87*. But where gas takes days to weeks to orbit the larger M87*, in the much smaller Sgr A* it completes an orbit in mere minutes. This means the brightness and pattern of the gas around Sgr A* were changing rapidly as the EHT Collaboration was observing it — a bit like trying to take a clear picture of a puppy quickly chasing its tail.”
The researchers had to develop sophisticated new tools that accounted for the gas movement around Sgr A*. While M87* was an easier, steadier target, with nearly all images looking the same, that was not the case for Sgr A*. The image of the Sgr A* black hole is an average of the different images the team extracted, finally revealing the giant lurking at the centre of our galaxy for the first time.
The effort was made possible through the ingenuity of more than 300 researchers from 80 institutes around the world that together make up the EHT Collaboration. In addition to developing complex tools to overcome the challenges of imaging Sgr A*, the team worked rigorously for five years, using supercomputers to combine and analyse their data, all while compiling an unprecedented library of simulated black holes to compare with the observations.
Scientists are particularly excited to finally have images of two black holes of very different sizes, which offers the opportunity to understand how they compare and contrast. They have also begun to use the new data to test theories and models of how gas behaves around supermassive black holes. This process is not yet fully understood but is thought to play a key role in shaping the formation and evolution of galaxies.
“Now we can study the differences between these two supermassive black holes to gain valuable new clues about how this important process works,” said EHT scientist Keiichi Asada from the Institute of Astronomy and Astrophysics, Academia Sinica, Taipei. “We have images for two black holes — one at the large end and one at the small end of supermassive black holes in the Universe — so we can go a lot further in testing how gravity behaves in these extreme environments than ever before.”
Progress on the EHT continues: a major observation campaign in March 2022 included more telescopes than ever before. The ongoing expansion of the EHT network and significant technological upgrades will allow scientists to share even more impressive images as well as movies of black holes in the near future.
This visible light wide-field view shows the rich star clouds in the constellation of Sagittarius (the Archer) in the direction of the centre of our Milky Way galaxy. The entire image is filled with vast numbers of stars — but far more remain hidden behind clouds of dust and are only revealed in infrared images. This view was created from photographs in red and blue light and form part of the Digitized Sky Survey 2. The field of view is approximately 3.5 degrees x 3.6 degrees. Credit:ESO and Digitized Sky Survey 2. Acknowledgment: Davide De Martin and S. Guisard (www.eso.org/~sguisard)
The black hole at the heart of our galaxy
Notes
[1] The individual telescopes involved in the EHT in April 2017, when the observations were conducted, were: the Atacama Large Millimeter/submillimeter Array (ALMA), the Atacama Pathfinder EXperiment (APEX), the IRAM 30-meter Telescope, the James Clerk Maxwell Telescope (JCMT), the Large Millimeter Telescope Alfonso Serrano (LMT), the Submillimeter Array (SMA), the UArizona Submillimeter Telescope (SMT), the South Pole Telescope (SPT). Since then, the EHT has added the Greenland Telescope (GLT), the NOrthern Extended Millimeter Array (NOEMA) and the UArizona 12-meter Telescope on Kitt Peak to its network.
ALMA is a partnership of the European Southern Observatory (ESO; Europe, representing its member states), the U.S. National Science Foundation (NSF), and the National Institutes of Natural Sciences (NINS) of Japan, together with the National Research Council (Canada), the Ministry of Science and Technology (MOST; Taiwan), Academia Sinica Institute of Astronomy and Astrophysics (ASIAA; Taiwan), and Korea Astronomy and Space Science Institute (KASI; Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, the Associated Universities, Inc./National Radio Astronomy Observatory (AUI/NRAO) and the National Astronomical Observatory of Japan (NAOJ). APEX, a collaboration between the Max Planck Institute for Radio Astronomy (Germany), the Onsala Space Observatory (Sweden) and ESO, is operated by ESO. The 30-meter Telescope is operated by IRAM (the IRAM Partner Organizations are MPG [Germany], CNRS [France] and IGN [Spain]). The JCMT is operated by the East Asian Observatory on behalf of The National Astronomical Observatory of Japan; ASIAA; KASI; the National Astronomical Research Institute of Thailand; the Center for Astronomical Mega-Science and organisations in the United Kingdom and Canada. The LMT is operated by INAOE and UMass, the SMA is operated by Center for Astrophysics | Harvard & Smithsonian and ASIAA and the UArizona SMT is operated by the University of Arizona. The SPT is operated by the University of Chicago with specialised EHT instrumentation provided by the University of Arizona.
The Greenland Telescope (GLT) is operated by ASIAA and the Smithsonian Astrophysical Observatory (SAO). The GLT is part of the ALMA-Taiwan project, and is supported in part by the Academia Sinica (AS) and MOST. NOEMA is operated by IRAM and the UArizona 12-meter telescope at Kitt Peak is operated by the University of Arizona.
A montage of the radio observatories that form the Event Horizon Telescope (EHT) network, used to image the Milky Way’s central black hole, Sagittarius A*. These include the Atacama Large Millimeter/submillimeter Array (ALMA), the Atacama Pathfinder EXperiment (APEX), IRAM 30-meter telescope, James Clark Maxwell Telescope (JCMT), Large Millimeter Telescope (LMT), Submillimeter Array (SMA), Submillimetere Telescope (SMT) and South Pole Telescope (SPT). The slightly transparent telescopes in the background, represent the three telescopes added to the EHT Collaboration after 2018: the Greenland Telescope, the NOrthern Extended Millimeter Array (NOEMA) in France, and the UArizona ARO 12-meter Telescope at Kitt Peak. These telescopes were added to the array after the 2017 observations of Sagittarius A*. Credit: ESO/M. Kornmesser. Images of individual telescopes: ALMA: ESO APEX: ESO LMT: INAOE Archives GLT: N. Patel JCMT: EAO-W. Montgomerie SMT: D. Harvey 30m: N. Billot SPT: Wikipedia SMA: S. R. Schimpf NOEMA: IRAM Kitt Peak: Wikipedia Milky Way: N. Risinger (skysurvey.org)A montage of the radio observatories that form the Event Horizon Telescope (EHT) network used to image the Milky Way’s central black hole, Sagittarius A*. These include the Atacama Large Millimeter/submillimeter Array (ALMA), the Atacama Pathfinder EXperiment (APEX), IRAM 30-meter telescope, James Clark Maxwell Telescope (JCMT), Large Millimeter Telescope (LMT), Submillimeter Array (SMA), Submillimeter Telescope (SMT) and South Pole Telescope (SPT). The slightly transparent telescopes in the background represent the three telescopes added to the EHT network after 2018: the Greenland Telescope, the NOrthern Extended Millimeter Array (NOEMA) in France, and the UArizona ARO 12-meter Telescope at Kitt Peak. These telescopes were added to the array after the 2017 observations of Sagittarius A*. Credit: ESO/M. Kornmesser. Images of individual telescopes: ALMA: ESO APEX: ESO LMT: INAOE Archives GLT: N. Patel JCMT: EAO-W. Montgomerie SMT: D. Harvey 30m: N. Billot SPT: Wikipedia SMA: S. R. Schimpf NOEMA: IRAM Kitt Peak: Wikipedia Milky Way: N. Risinger (skysurvey.org)
[2] A strong basis for the interpretation of this new image was provided by previous research carried out on Sgr A*. Astronomers have known the bright, dense radio source at the centre of the Milky Way in the direction of the constellation Sagittarius since the 1970s. By measuring the orbits of several stars very close to our galactic centre over a period of 30 years, teams led by Reinhard Genzel (Director at the Max –Planck Institute for Extraterrestrial Physics in Garching near Munich, Germany) and Andrea M. Ghez (Professor in the Department of Physics and Astronomy at the University of California, Los Angeles, USA) were able to conclude that the most likely explanation for an object of this mass and density is a supermassive black hole. ESO’s facilities (including the Very Large Telescope and the Very Large Telescope Interferometer) and the Keck Observatory were used to carry out this research, which shared the 2020 Nobel Prize in Physics.
[3] Black holes are the only objects we know of where mass scales with size. A black hole a thousand times smaller than another is also a thousand times less massive.
The black hole at the heart of our galaxy: more information
This research was presented in six papers published today in The Astrophysical Journal Letters.
A global map showing the radio observatories that form the Event Horizon Telescope (EHT) network used to image the Milky Way’s central black hole, Sagittarius A*. The telescopes highlighted in yellow were part of the EHT network during the observations of Sagittarius A* in 2017. These include the Atacama Large Millimeter/submillimeter Array (ALMA), the Atacama Pathfinder EXperiment (APEX), IRAM 30-meter telescope, James Clark Maxwell Telescope (JCMT), Large Millimeter Telescope (LMT), Submillimeter Array (SMA), Submillimetere Telescope (SMT) and South Pole Telescope (SPT). Highlighted in blue are the three telescopes added to the EHT Collaboration after 2018: the Greenland Telescope, the NOrthern Extended Millimeter Array (NOEMA) in France, and the UArizona ARO 12-meter Telescope at Kitt Peak. Credit:ESO/M. Kornmesser
The EHT collaboration involves more than 300 researchers from Africa, Asia, Europe, North and South America. The international collaboration aims to capture the most detailed black hole images ever obtained by creating a virtual Earth-sized telescope. Supported by considerable international efforts, the EHT links existing telescopes using novel techniques — creating a fundamentally new instrument with the highest angular resolving power that has yet been achieved.
This image shows the locations of some of the telescopes making up the EHT, as well as a representation of the long baselines between the telescopes. Credit:ESO/L. Calçada
The EHT consortium consists of 13 stakeholder institutes; the Academia Sinica Institute of Astronomy and Astrophysics, the University of Arizona, the Center for Astrophysics | Harvard & Smithsonian, the University of Chicago, the East Asian Observatory, Goethe-Universitaet Frankfurt, Institut de Radioastronomie Millimétrique, Large Millimeter Telescope, Max Planck Institute for Radio Astronomy, MIT Haystack Observatory, National Astronomical Observatory of Japan, Perimeter Institute for Theoretical Physics, and Radboud University.
This view shows several of the ALMA antennas and the central regions of the Milky Way above. In this wide field view, the zodiacal light is seen upper right and at lower left Mars is seen. Saturn is a bit higher in the sky towards the centre of the image. The image was taken during the ESO Ultra HD (UHD) Expedition. Credit:ESO/B. Tafreshi (twanight.org)
The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the Ministry of Science and Technology (MOST) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI). ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.
The slumbering Atacama Pathfinder Experiment (APEX) telescope sits beneath reddened skies amongst the snow covered Chajnantor landscape. Snow not only blankets the ground, but also the many peaks that encircle the Chilean plateau which also hosts the Atacama Large Millimeter/submillimeter Array (ALMA). Credit:Carlos A. Durán/ESO
APEX, Atacama Pathfinder EXperiment, is a 12-metre diameter telescope, operating at millimetre and submillimetre wavelengths — between infrared light and radio waves. ESO operates APEX at one of the highest observatory sites on Earth, at an elevation of 5100 metres, high on the Chajnantor plateau in Chile’s Atacama region. The telescope is a collaboration between the Max Planck Institute for Radio Astronomy (MPIfR), the Onsala Space Observatory (OSO), and ESO.
This image shows the dish of the Atacama Pathfinder Experiment (APEX) telescope seen perfectly from the side, including the starry sky. Credit:C. Duran/ESOESO Photo Ambassador Stéphane Guisard captured this astounding panorama from the site of ALMA, the Atacama Large Millimeter/submillimeter Array, in the Chilean Andes. The 5000-metre-high and extremely dry Chajnantor plateau offers the perfect place for this state-of-the-art telescope, which studies the Universe in millimetre- and submillimetre-wavelength light. Numerous giant antennas dominate the centre of the image. When ALMA is complete, it will have a total of 54 of these 12-metre-diameter dishes. Above the array, the arc of the Milky Way serves as a resplendent backdrop. When the panorama was taken, the Moon was lying close to the centre of the Milky Way in the sky, its light bathing the antennas in an eerie night-time glow. The Large and Small Magellanic Clouds, the biggest of the Milky Way’s dwarf satellite galaxies, appear as two luminous smudges in the sky on the left. A particularly bright meteor streak gleams near the Small Magellanic Cloud. On the right, some of ALMA’s smaller 7-metre antennas — twelve of which will be used to form the Atacama Compact Array — can be seen. Still further on the right shine the lights of the Array Operations Site Technical Building. And finally, looming behind this building is the dark, mountainous peak of Cerro Chajnantor. ALMA, an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA. Links ESO Photo Ambassadors More about ALMA at ESO The Joint ALMA Observatory. Links ESO Photo Ambassadors More about ALMA at ESO The Joint ALMA Observatory Credit:ESO/S. Guisard (www.eso.org/~sguisard)
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 in astronomy. Established as an intergovernmental organisation in 1962, today ESO is supported by 16 Member States (Austria, Belgium, the Czech Republic, 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 two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. 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 APEX and ALMA on Chajnantor, two facilities that observe 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.
The black hole at the heart of our galaxy. This is the first image of Sgr A*, the supermassive black hole at the centre of our galaxy, with an added black background to fit wider screens. It’s the first direct visual evidence of the presence of this black hole. It was captured by the Event Horizon Telescope (EHT), an array which linked together eight existing radio observatories across the planet to form a single “Earth-sized” virtual telescope. The telescope is named after the event horizon, the boundary of the black hole beyond which no light can escape. Although we cannot see the event horizon itself, because it cannot emit light, glowing gas orbiting around the black hole reveals a telltale signature: a dark central region (called a shadow) surrounded by a bright ring-like structure. The new view captures light bent by the powerful gravity of the black hole, which is four million times more massive than our Sun. The image of the Sgr A* black hole is an average of the different images the EHT Collaboration has extracted from its 2017 observations. In addition to other facilities, the EHT network of radio observatories that made this image possible includes the Atacama Large Millimeter/submillimeter Array (ALMA) and the Atacama Pathfinder EXperiment (APEX) in the Atacama Desert in Chile, co-owned and co-operated by ESO is a partner on behalf of its member states in Europe. Credit:EHT Collaboration
Supermassive Black Hole Precursor Detected in Archival Hubble Data
An international team of astronomers using archival data from the NASA/ESA Hubble Space Telescope and other space- and ground-based observatories have discovered a unique object in the distant, early Universe that is a crucial link between star-forming galaxies and the emergence of the earliest supermassive black holes. This object is the first of its kind to be discovered so early in the Universe’s history, and had been lurking unnoticed in one of the best-studied areas of the night sky.
Astronomers have struggled to understand the emergence of supermassive black holes in the early Universe ever since these objects were discovered at distances corresponding to a time only 750 million years after the Big Bang[1]. Rapidly growing black holes in dusty, early star-forming galaxies are predicted by theories and computer simulations but until now they had not been observed. Now, however, astronomers have reported the discovery of an object — which they name GNz7q — that is believed to be the first such rapidly growing black hole to be found in the early Universe. Archival Hubble data from the Advanced Camera for Surveys helped the team study the compact ultraviolet emission from the black hole’s accretion disc and to determine that GNz7q existed just 750 million years after the Big Bang.
“Our analysis suggests that GNz7q is the first example of a rapidly-growing black hole in the dusty core of a starburst galaxy at an epoch close to the earliest super massive black hole known in the Universe,” explains Seiji Fujimoto, an astronomer at the Niels Bohr Institute of the University of Copenhagen in Denmark and lead author of the paper describing this discovery. “The object’s properties across the electromagnetic spectrum are in excellent agreement with predictions from theoretical simulations.”
Supermassive Black Hole Precursor Detected in Archival Hubble Data: Crop of the GNz7q in the Hubble GOODS-North field. An international team of astronomers using archival data from the NASA/ESA Hubble Space Telescope and other space- and ground-based observatories have discovered a unique object in the distant, early Universe that is a crucial link between young star-forming galaxies and the earliest supermassive black holes. This object is the first of its kind to be discovered so early in the Universe’s history, and had been lurking unnoticed in one of the best-studied areas of the night sky. The object, which is referred to as GNz7q, is shown here in the centre of the image of the Hubble GOODS-North field. Credit: NASA, ESA, G. Illingworth (University of California, Santa Cruz), P. Oesch (University of California, Santa Cruz; Yale University), R. Bouwens and I. Labbé (Leiden University), and the Science Team, S. Fujimoto et al. (Cosmic Dawn Center [DAWN] and University of Copenhagen)
Current theories predict that supermassive black holes begin their lives in the dust-shrouded cores of vigorously star-forming “starburst” galaxies before expelling the surrounding gas and dust and emerging as extremely luminous quasars. Whilst they are extremely rare, examples of both dusty starburst galaxies and luminous quasars have been detected in the early Universe. The team believes that GNz7q could be the “missing link” between these two classes of objects.
“GNz7q provides a direct connection between these two rare populations and provides a new avenue towards understanding the rapid growth of supermassive black holes in the early days of the Universe,” continued Fujimoto. “Our discovery is a precursor of the supermassive black holes we observe at later epochs.”
Whilst other interpretations of the team’s data cannot be completely ruled out, the observed properties of GNz7q are in strong agreement with theoretical predictions. GNz7q’s host galaxy is forming stars at the rate of 1600 solar masses of stars per year [2] and GNz7q itself appears bright at ultraviolet wavelengths but very faint at X-ray wavelengths. The team have interpreted this — along with the host galaxy’s brightness at infrared wavelengths — to suggest that GNz7q is harbors a rapidly growing black hole still obscured by the dusty core of its accretion disc at the center of the star-forming host galaxy.
Supermassive Black Hole Precursor Detected in Archival Hubble Data: GNz7q in the Hubble GOODS-North field. An international team of astronomers using archival data from the NASA/ESA Hubble Space Telescope and other space- and ground-based observatories have discovered a unique object in the distant, early Universe that is a crucial link between young star-forming galaxies and the earliest supermassive black holes. This object is the first of its kind to be discovered so early in the Universe’s history, and had been lurking unnoticed in one of the best-studied areas of the night sky. The object, which is referred to as GNz7q, is shown here in the centre of the cutout from the Hubble GOODS-North field. Credit: NASA, ESA, G. Illingworth (University of California, Santa Cruz), P. Oesch (University of California, Santa Cruz; Yale University), R. Bouwens and I. Labbé (Leiden University), and the Science Team, S. Fujimoto et al. (Cosmic Dawn Center [DAWN] and University of Copenhagen)
As well as GNz7q’s importance to the understanding of the origins of supermassive black holes, this discovery is noteworthy for its location in the Hubble GOODS North field, one of the most highly scrutinised areas of the night sky [3].
“GNz7q is a unique discovery that was found just at the centre of a famous, well-studied sky field — showing that big discoveries can often be hidden just in front of you,” commented Gabriel Brammer, another astronomer from the Niels Bohr Institute of the University of Copenhagen and a member of the team behind this result. “It’s unlikely that discovering GNz7q within the relatively small GOODS-N survey area was just ‘dumb luck’ rather the prevalence of such sources may in fact be significantly higher than previously thought.”
Finding GNz7q hiding in plain sight was only possible thanks to the uniquely detailed, multi-wavelength datasets available for GOODS-North. Without this richness of data GNz7q would have been easy to overlook, as it lacks the distinguishing features usually used to identify quasars in the early Universe. The team now hopes to systematically search for similar objects using dedicated high-resolution surveys and to take advantage of the NASA/ESA/CSA James Webb Space Telescope’s spectroscopic instruments to study objects such as GNz7q in unprecedented detail.
“Fully characterising these objects and probing their evolution and underlying physics in much greater detail will become possible with the James Webb Space Telescope.” concluded Fujimoto. “Once in regular operation, Webb will have the power to decisively determine how common these rapidly growing black holes truly are.”
Supermassive Black Hole Precursor Detected in Archival Hubble Data: Artist’s Impression of GNz7q. An international team of astronomers using archival data from the NASA/ESA Hubble Space Telescope and other space- and ground-based observatories have discovered a unique object in the distant, early Universe that is a crucial link between young star-forming galaxies and the earliest supermassive black holes. This object is the first of its kind to be discovered so early in the Universe’s history, and had been lurking unnoticed in one of the best-studied areas of the night sky. Current theories predict that supermassive black holes begin their lives in the dust-shrouded cores of vigorously star-forming “starburst” galaxies before expelling the surrounding gas and dust and emerging as extremely luminous quasars. Whilst they are extremely rare, examples of both dusty starburst galaxies and luminous quasars have been detected in the early Universe. The team believes that GNz7q could be the “missing link” between these two classes of objects. Credit: ESA/Hubble, N. Bartmann
Notes
[1] Whilst light travels imperceptibly quickly in day-to-day life, the vast distances in astronomy mean that as astronomers look at increasingly distant objects, they are also looking backwards in time. For example, light from the Sun takes around 8.3 minutes to reach Earth, meaning that we view the Sun as it was 8.3 minutes ago. The most distant objects are the furthest back in time, meaning that astronomers studying very distant galaxies are able to study the earliest periods of the Universe.
[2] This does not mean that 1600 Sun-like stars are produced each year in GNz7q’s host galaxy, but rather that a variety of stars are formed each year with a total mass 1600 times that of the Sun.
[3] GOODS — the Great Observatories Origins Deep Survey — is an astronomical survey that combines multi-wavelength observations from some of the most capable telescopes ever built, including Hubble, ESA’s Herschel and XMM-Newton space telescopes, NASA’s Spitzer Space Telescope and Chandra X-ray Observatory, and powerful ground-based telescopes.
Supermassive Black Hole Precursor: more information
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
These results have been published in Nature.
The international team of astronomers in this study consists of S. Fujimoto (Cosmic Dawn Center [DAWN] and Niels Bohr Institute, University of Copenhagen, Denmark), G. B. Brammer (DAWN and Niels Bohr Institute, University of Copenhagen, Denmark), D. Watson (DAWN and Niels Bohr Institute, University of Copenhagen, Denmark), G. E. Magdis (DAWN, DTU-Space at the Technical University of Denmark, and Niels Bohr Institute at the University of Copenhagen, Denmark), V. Kokorev (DAWN and Niels Bohr Institute, University of Copenhagen, Denmark), T. R. Greve (DAWN and DTU-Space, Technical University of Denmark, Denmark), S. Toft (DAWN and Niels Bohr Institute, University of Copenhagen, Denmark), F. Walter ( DAWN, Denmark, the Max Planck Institute for Astronomy, Germany, and the National Radio Astronomy Observatory, USA), R. Valiante (INAF-Osservatorio Astronomico di Roma, Rome, Italy), M. Ginolfi (European Southern Observatory, Garching, Germany), R. Schneider (INAF-Osservatorio Astronomico di Roma, Rome, Italy and Dipartimento di Fisica, Universitá di Roma La Sapienza, Rome, Italy), F. Valentino (DAWN and Niels Bohr Institute, University of Copenhagen, Denmark), L. Colina (DAWN, Copenhagen, Denmark and Centro de Astrobiología (CAB, CSIC-INTA), Madrid, Spain), M. Vestergaard (Niels Bohr Institute, University of Copenhagen, Denmark, and Steward Observatory, University of Arizona, USA), R. Marques-Chaves (Geneva Observatory, University of Geneva, Switzerland), J. P. U. Fynbo (DAWN and Niels Bohr Institute, University of Copenhagen, Denmark), M. Krips (IRAM, Domaine Universitaire, Saint-Martin-d’Hères, France), C. L. Steinhardt (DAWN and Niels Bohr Institute, University of Copenhagen, Denmark), I. Cortzen (IRAM, Domaine Universitaire, Saint-Martin-d’Hères, France), F. Rizzo (DAWN and Niels Bohr Institute, University of Copenhagen, Denmark), and P. A. Oesch (DAWN, Copenhagen, Denmark and Geneva Observatory, University of Geneva, Switzerland).
New species of stegosaur is oldest discovered in Asia, and possibly the world
Bashanosaurus primitivus roamed the earth around 168 million years ago during the Middle Jurassic period, suggesting that stegosaurs may have originated in Asia
Bashanosaurus primitivus – the newest and oldest species of stegosaur in Asia. Bashanosaurus primitivus roamed the earth around 168 million years ago during the Middle Jurassic period, suggesting that stegosaurs may have originated in Asia. Credits: Credit Banana Art Studio
Relatively small, but fearsome-looking stegosaur measured about 2.8 metres (9 feet) from nose to tail—but scientists can’t tell whether the remains are those of an adult or juvenile.
A new species of one of the most recognisable types of dinosaur is the oldest stegosaur ever found in Asia, and one of the earliest unearthed anywhere in the world, according to research published today in the peer-reviewed Journal of Vertebrate Paleontology.
Remains of the stegosaur, which included bones from the back, shoulder, thigh, feet, and ribs, as well as several armour plates, date to the Bajocian stage of the Middle Jurassic period – much earlier than most known stegosaurs.
A team from the Chongqing Bureau of Geological and Mineral Resource Exploration and Development in China and London’s Natural History Museum named it Bashanosaurus primitivus – “Bashan” in reference to the ancient name for the area of Chongqing in China where the dinosaur was found, and the Latin for ‘first’ – primitivus.
The new dinosaur, which roamed the planet 168 million years ago, plays a part in uncovering how the stegosaurs evolved – of which, to this day, little is known.
It has a smaller and less developed should blade, narrower and thicker bases to its armour plates and other features that are different from all other Middle Jurassic stegosaurs discovered so far. However, it does have similarities with some of the first armoured dinosaurs, which are over 20 million years older.
“All these features are clues to the stegosaurs’ place on the dinosaur family tree”, says Dr Dai Hui from Chongqing Bureau of Geological and Mineral Resource Exploration and Development who led the research. “Bashanosaurus can be distinguished fromother Middle Jurassic stegosaurs, and clearly represents a new species.
“What’s more, our analysis of the family tree indicates that it is one of the earliest-diverging stegosaurs along with the Chongqing Lizard (Chungkingosaurus) and Huayangosaurus. These were all unearthed from the Middle to Late Jurassic Shaximiao Formation in China, suggesting that stegosaurs might have originated in Asia”, adds Hui.
Instantly recognisable by the huge back plates, long tail spikes and tiny head, stegosaurs were four-legged, plant-eating dinosaurs that lived during the Jurassic and early Cretaceous periods. Stegosaur fossils have been found on all continents except for Antarctica and Australia, and 14 species of stegosaur have been identified so far.
Well-known members of Stegosauria include Huayangosaurus (one of the most primitive stegosaurs), Gigantspinosaurus, notable for its enormous shoulder spines, and Miragaia for its extremely long neck. However, the fragmentary fossil material has hindered attempts to understand how the stegosaurs evolved and how they relate to one another.
With the discovery of this new species the mystery has started to clear up. Bashanosaurus primitivus has several primitive features that are similar to the earliest stegosaurs like Huayangosaurus and Gigantspinosaurus and early-branching thyreophorans (armoured dinosaurs). These include longer tail vertebrae, a shoulder blade that is narrower and flares out, and features of the back vertebrae that are similar to the early armoured dinosaur Scelidosaurus, which lived during the Early Jurassic.
The fossilised remains of Bashanosaurus also reveal a host of features that make it unique from other known stegosaurs. For example, the bony point at the end of the shoulder blade is small and less well developed than in other stegosaurs; a bony projection of the thighbone (fourth trochanter) is positioned below the middle of the shaft; and the bases of the armour plates curve outwards and are thicker than the plates on the backs of its later relatives.
“The discovery of this stegosaur from the Middle Jurassic of China adds to an increasing body of evidence that the group evolved in the early Middle Jurassic, or perhaps even in the Early Jurassic, and as such represent some of the earliest known bird-hipped dinosaurs,” says Dr Susannah Maidment, co-author and palaeontologist at London’s Natural History Museum.
“China seems to have been a hotspot for stegosaur diversity, with numerous species now known from the Middle Jurassic right the way through until the end of the Early Cretaceous period.”
New stegosaurs from the Middle Jurassic Lower Member of the Shaximiao Formation of Chongqing, China, Journal of Vertebrate Paleontology (4/03/2022), DOI: 10.1080/02724634.2021.1995737
A new paper by SISSA and University of Padua on a large sample of the Italian population shows that occupation influences the course of cognitive decline
Trieste, 9 Dec 2021 – A recent study shows that work plays an active role in keeping our brains healthy. “We have demonstrated the role of working activity on cognitive performance”. Professor Raffaella Rumiati says. She is cognitive neuroscientist at SISSA and author of the paper Protective factor for Subjective Cognitive Decline Individuals: Trajectories and change in a longitudinal study with Italian seniors, recently published in the European Journal of Neurology. DOI: https://doi.org/10.1111/ene.15183
“Many studies have been focused on the factors influencing our brain aging and differences in cognitive decline have been often observed in association with education or other related to quality of life. From our analysis it emerges that the type of work activity also contributes to the differences in normal and pathological cognitive aging”.
The analysis: resistant and declining brains
The research, carried out by a team of scientists from the University of Padua (Dip. FISPPA), SISSA – Scuola Internazionale di Studi Superiori Avanzati and IRCSS San Camillo Hospital in Venice, quantified the relative contribution of demographic factors (age and sex), comorbidity, education and occupation to the so-called cognitive reserve, that is brain’s resistance to a damage caused by illness or aging. Participants were assessed with a series of neuropsychological tests and subsequently divided into three types of profiles based on the results: subjects at risk of cognitive decline, subjects with mild decline and subjects with severe decline.
The tests were repeated twice a few years apart. Depending on whether they maintained or worsened their profile based on their initial performance, participants were classified as “resistant” or “declining”.
Education and occupation to stay young
The analysis surprisingly shows that occupation is a good predictor of participants’ performance in addition to age and education, two factors that have been already studied.
Professor Sara Mondini of the University of Padua says:
“We confirmed that education protect people from the risk of cognitive decline and that these individuals had held more complex occupations than the individuals of the other two groups, the subjects with mild and advanced cognitive decline. Furthermore, the study showed how “resistant” group has on average higher levels of education and more complex jobs than the “declining” group.”
The results demonstrate benefits of cognitive mobilization promoted by lifelong learning and that social connection, ongoing sense of purpose and ability to function independently largely affect cognitive health and general well-being along the trajectories of aging.
Press release from the University of Padua and SISSA – Scuola Internazionale Superiore di Studi Avanzati.
Rocks on floor of Jezero Crater, Mars, show signs of sustained interactions with water
Rocks on floor of Jezero Crater, Mars, show signs of sustained interactions with water. Perseverance rover taking a selfie over the rock it collected two core samples from on Mars. Perseverance rover taking a selfie over the rock it collected two core samples from on Mars. Image credit NASA/JPL-Caltech/MSSS
Portland, Ore., USA:Since the Perseverance rover landed in Jezero crater on Mars in February, the rover and its team of scientists back on Earth have been hard at work exploring the floor of the crater that once held an ancient lake. Perseverance and the Mars 2020 mission are looking for signs of ancient life on Mars and preparing a returnable cache of samples for later analyses on Earth.
Katie Stack Morgan is the Mars 2020 Deputy Project Scientist and a research scientist at NASA’s Jet Propulsion Laboratory (JPL), and will be providing an update on early results on the Mars 2020 rover mission on Sunday, 10 Oct., at the Geological Society of America’s Connects 2021 annual meeting in Portland, Oregon.
With Perseverance’s high-tech suite of on-board instruments, the scientific team has been analyzing the rocks of the crater floor, interpreted for now as igneous rocks, presumably a volcanic lava flow.
“The idea that this could be a volcanic rock was really appealing to us from a sample return perspective because igneous rocks are great for getting accurate age dates. Jezero was one of the few ancient crater lake sites on Mars that seemed to have both incredible sedimentary deposits as well as volcanic deposits that could help us construct the geologic time scale of Mars,” said Stack Morgan.
The lake system and rivers that drained into Jezero crater were likely active around 3.8–3.6 billion years ago, but the ability to directly date the age of the rocks in laboratories on Earth will provide the first definitive insight into the window of time that Mars may have been a habitable planet.
Using Perseverance’s abrasion tool—which scratches the top surface of the rock to reveal the rock and its textures—the team discovered that the crater floor seems to be composed of coarser-grained igneous minerals, and there are also a variety of salts in the rocks. Observations suggest that water caused extensive weathering and alteration of the crater floor, meaning that the rocks were subjected to water for a significant duration of time.
After using its on-board tools to analyze characteristics of the crater floor, the next phase was for Perseverance to collect a rock sample using its drill feature. However, after Perseverance completed its first attempt at drilling, the core sample tube came up empty.
“We spent a couple of days looking around the rover thinking that the core might have fallen out of the bit. Then we looked back down the drill hole thinking it might never have made it out of the hole. All these searches turned up empty. In the end we concluded that the core was pulverized during drilling,” said Stack Morgan.
The rock likely became so altered and weakened from interactions with water that the vibrations and strength from the Perseverance drill pulverized the sample.
Scientists then targeted another rock that appeared more resistant to weathering, and Perseverance was able to successfully collect two core samples—the first in its sample collection. Perseverance’s cache of samples will be part of a multi-spacecraft handoff, still in development, that will hopefully be returned to Earth in the early 2030s. From there, scientists in laboratories on Earth will date and analyze the rocks to see if there might be any signs of ancient Martian life.
“The rocks of the crater floor were not originally envisioned as the prime astrobiology target of the mission, but Mars always surprises us when we look up close. We are excited to find that even these rocks have experienced sustained interaction with water and could have been habitable for ancient martian microbes,” said Stack Morgan.
Hubble data confirms galaxies lacking dark matter: NGC1052-DF2. Credits: NASA, ESA, Z. Shen and P. van Dokkum (Yale University), and S. Danieli (Institute for Advanced Study)
The most accurate distance measurement yet of ultra-diffuse galaxy (UDG) NGC1052-DF2 (DF2) confirms beyond any shadow of a doubt that it is lacking in dark matter. The newly measured distance of 22.1 +/-1.2 megaparsecs was obtained by an international team of researchers led by Zili Shen and Pieter van Dokkum of Yale University and Shany Danieli, a NASA Hubble Fellow at the Institute for Advanced Study.
“Determining an accurate distance to DF2 has been key in supporting our earlier results,” stated Danieli. “The new measurement reported in this study has crucial implications for estimating the physical properties of the galaxy, thus confirming its lack of dark matter.”
The results, published in Astrophysical Journal Letters on June 9, 2021, are based on 40 orbits of NASA’s Hubble Space Telescope, with imaging by the Advanced Camera for Surveys and a “tip of the red giant branch” (TRGB) analysis, the gold standard for such refined measurements. In 2019, the team published results measuring the distance to neighboring UDG NGC1052-DF4 (DF4) based on 12 Hubble orbits and TRGB analysis, which provided compelling evidence of missing dark matter. This preferred method expands on the team’s 2018 studies that relied on “surface brightness fluctuations” to gauge distance. Both galaxies were discovered with the Dragonfly Telephoto Array at the New Mexico Skies observatory.
Hubble data confirms galaxies lacking dark matter: NGC1052-DF2. Credits: NASA, ESA, Z. Shen and P. van Dokkum (Yale University), and S. Danieli (Institute for Advanced Study)
“We went out on a limb with our initial Hubble observations of this galaxy in 2018,” van Dokkum said. “I think people were right to question it because it’s such an unusual result. It would be nice if there were a simple explanation, like a wrong distance. But I think it’s more fun and more interesting if it actually is a weird galaxy.”
In addition to confirming earlier distance findings, the Hubble results indicated that the galaxies were located slightly farther away than previously thought, strengthening the case that they contain little to no dark matter. If DF2 were closer to Earth, as some astronomers claim, it would be intrinsically fainter and less massive, and the galaxy would need dark matter to account for the observed effects of the total mass.
Dark matter is widely considered to be an essential ingredient of galaxies, but this study lends further evidence that its presence may not be inevitable. While dark matter has yet to be directly observed, its gravitational influence is like a glue that holds galaxies together and governs the motion of visible matter. In the case of DF2 and DF4, researchers were able to account for the motion of stars based on stellar mass alone, suggesting a lack or absence of dark matter. Ironically, the detection of galaxies deficient in dark matter will likely help to reveal its puzzling nature and provide new insights into galactic evolution.
While DF2 and DF4 are both comparable in size to the Milky Way galaxy, their total masses are only about one percent of the Milky Way’s mass. These ultra-diffuse galaxies were also found to have a large population of especially luminous globular clusters.
This research has generated a great deal of scholarly interest, as well as energetic debate among proponents of alternative theories to dark matter, such as Modified Newtonian dynamics (MOND). However, with the team’s most recent findings–including the relative distances of the two UDGs to NGC1052–such alternative theories seem less likely. Additionally, there is now little uncertainty in the team’s distance measurements given the use of the TRGB method. Based on fundamental physics, this method depends on the observation of red giant stars that emit a flash after burning through their helium supply that always happens at the same brightness.
“There’s a saying that extraordinary claims require extraordinary evidence, and the new distance measurement strongly supports our previous finding that DF2 is missing dark matter,” stated Shen. “Now it’s time to move beyond the distance debate and focus on how such galaxies came to exist.”
Moving forward, researchers will continue to hunt for more of these oddball galaxies, while considering a number of questions such as: How are UDGs formed? What do they tell us about standard cosmological models? How common are these galaxies, and what other unique properties do they have? It will take uncovering many more dark matter-less galaxies to resolve these mysteries and the ultimate question of what dark matter really is.
The Institute for Advanced Study is one of the world’s foremost centers for theoretical research and intellectual inquiry. Located in Princeton, N.J., the IAS is dedicated to independent study across the sciences and humanities. Founded in 1930, the Institute is devoted to advancing the frontiers of knowledge without concern for immediate application. From founding IAS Professor Albert Einstein to the foremost thinkers of today, the IAS enables bold, curiosity-driven innovation to enrich society in unexpected ways.
Each year, the Institute welcomes more than 200 of the world’s most promising post-doctoral researchers and scholars who are selected and mentored by a permanent Faculty, each of whom are preeminent leaders in their fields. Among present and past Faculty and Members there have been 35 Nobel Laureates, 42 of the 60 Fields Medalists, and 21 of the 24 Abel Prize Laureates, as well as many MacArthur Fellows and Wolf Prize winners.
NASA Selects 2 Missions to Study ‘Lost Habitable’ World of Venus
NASA has selected two new missions to Venus, Earth’s nearest planetary neighbor. Part of NASA’s Discovery Program, the missions aim to understand how Venus became an inferno-like world when it has so many other characteristics similar to ours – and may have been the first habitable world in the solar system, complete with an ocean and Earth-like climate.
These investigations are the final selections from four mission concepts NASA picked in February 2020 as part of the agency’s Discovery 2019 competition. Following a competitive, peer-review process, the two missions were chosen based on their potential scientific value and the feasibility of their development plans. The project teams will now work to finalize their requirements, designs, and development plans.
NASA is awarding approximately $500 million per mission for development. Each is expected to launch in the 2028-2030 timeframe.
NASA Selects 2 Missions to Study ‘Lost Habitable’ World of Venus. Venus hides a wealth of information that could help us better understand Earth and exoplanets. NASA’s JPL is designing mission concepts to survive the planet’s extreme temperatures and atmospheric pressure. This image is a composite of data from NASA’s Magellan spacecraft and Pioneer Venus Orbiter. Credits: NASA/JPL-Caltech
The selected missions are:
DAVINCI+ (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging)
DAVINCI+ will measure the composition of Venus’ atmosphere to understand how it formed and evolved, as well as determine whether the planet ever had an ocean. The mission consists of a descent sphere that will plunge through the planet’s thick atmosphere, making precise measurements of noble gases and other elements to understand why Venus’ atmosphere is a runaway hothouse compared the Earth’s.
In addition, DAVINCI+ will return the first high resolution pictures of the unique geological features on Venus known as “tesserae,” which may be comparable to Earth’s continents, suggesting that Venus has plate tectonics. This would be the first U.S.-led mission to Venus’ atmosphere since 1978, and the results from DAVINCI+ could reshape our understanding of terrestrial planet formation in our solar system and beyond. James Garvin of Goddard Space Flight Center in Greenbelt, Maryland, is the principal investigator. Goddard provides project management.
VERITAS (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy)
VERITAS will map Venus’ surface to determine the planet’s geologic history and understand why it developed so differently than Earth. Orbiting Venus with a synthetic aperture radar, VERITAS will chart surface elevations over nearly the entire planet to create 3D reconstructions of topography and confirm whether processes such as plate tectonics and volcanism are still active on Venus.
VERITAS also will map infrared emissions from Venus’ surface to map its rock type, which is largely unknown, and determine whether active volcanoes are releasing water vapor into the atmosphere. Suzanne Smrekar of NASA’s Jet Propulsion Laboratory in Southern California, is the principal investigator. JPL provides project management. The German Aerospace Center will provide the infrared mapper with the Italian Space Agency and France’s Centre National d’Études Spatiales contributing to the radar and other parts of the mission.
“We’re revving up our planetary science program with intense exploration of a world that NASA hasn’t visited in over 30 years,” said Thomas Zurbuchen, NASA’s associate administrator for science. “Using cutting-edge technologies that NASA has developed and refined over many years of missions and technology programs, we’re ushering in a new decade of Venus to understand how an Earth-like planet can become a hothouse. Our goals are profound. It is not just understanding the evolution of planets and habitability in our own solar system, but extending beyond these boundaries to exoplanets, an exciting and emerging area of research for NASA.”
Zurbuchen added that he expects powerful synergies across NASA’s science programs, including the James Webb Space Telescope. He anticipates data from these missions will be used by the broadest possible cross section of the scientific community.
“It is astounding how little we know about Venus, but the combined results of these missions will tell us about the planet from the clouds in its sky through the volcanoes on its surface all the way down to its very core,” said Tom Wagner, NASA’s Discovery Program scientist. “It will be as if we have rediscovered the planet.”
In addition to the two missions, NASA selected a pair of technology demonstrations to fly along with them. VERITAS will host the Deep Space Atomic Clock-2, built by JPL and funded by NASA’s Space Technology Mission Directorate. The ultra-precise clock signal generated with this technology will ultimately help enable autonomous spacecraft maneuvers and enhance radio science observations.
DAVINCI+ will host the Compact Ultraviolet to Visible Imaging Spectrometer (CUVIS) built by Goddard. CUVIS will make high resolution measurements of ultraviolet light using a new instrument based on freeform optics. These observations will be used to determine the nature of the unknown ultraviolet absorber in Venus’ atmosphere that absorbs up to half the incoming solar energy.
Established in 1992, NASA’s Discovery Program has supported the development and implementation of over 20 missions and instruments. These selections are part of the ninth Discovery Program competition.
The concepts were chosen from proposals submitted in 2019 under NASA Announcement of Opportunity NNH19ZDA010O. The selected investigations will be managed by the Planetary Missions Program Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama, as part of the Discovery Program. The Discovery Program conducts space science investigations in the Planetary Science Division of NASA’s Science Mission Directorate. The goals of the program are to provide frequent opportunities for principal investigator-led investigations in planetary sciences that can be accomplished under a not-to-exceed cost cap.
First results from Fermilab’s Muon g-2 experiment strengthen evidence of new physics
The long-awaited first results from the Muon g-2 experiment at the U.S. Department of Energy’s Fermi National Accelerator Laboratory show fundamental particles called muons behaving in a way that is not predicted by scientists’ best theory, the Standard Model of particle physics. This landmark result, made with unprecedented precision, confirms a discrepancy that has been gnawing at researchers for decades.
The strong evidence that muons deviate from the Standard Model calculation might hint at exciting new physics. Muons act as a window into the subatomic world and could be interacting with yet undiscovered particles or forces.
“Today is an extraordinary day, long awaited not only by us but by the whole international physics community,” said Graziano Venanzoni, co-spokesperson of the Muon g-2 experiment and physicist at the Italian National Institute for Nuclear Physics. “A large amount of credit goes to our young researchers who, with their talent, ideas and enthusiasm, have allowed us to achieve this incredible result.”
First results from the Muon g-2 experiment at Fermilab have strengthened evidence of new physics. The centerpiece of the experiment is a 50-foot-diameter superconducting magnetic storage ring, which sits in its detector hall amidst electronics racks, the muon beamline, and other equipment. This impressive experiment operates at negative 450 degrees Fahrenheit and studies the precession (or wobble) of muons as they travel through the magnetic field. Photo: Reidar Hahn, Fermilab
A muon is about 200 times as massive as its cousin, the electron. Muons occur naturally when cosmic rays strike Earth’s atmosphere, and particle accelerators at Fermilab can produce them in large numbers. Like electrons, muons act as if they have a tiny internal magnet. In a strong magnetic field, the direction of the muon’s magnet precesses, or wobbles, much like the axis of a spinning top or gyroscope. The strength of the internal magnet determines the rate that the muon precesses in an external magnetic field and is described by a number that physicists call the g-factor. This number can be calculated with ultra-high precision.
As the muons circulate in the Muon g-2 magnet, they also interact with a quantum foam of subatomic particles popping in and out of existence. Interactions with these short-lived particles affect the value of the g-factor, causing the muons’ precession to speed up or slow down very slightly. The Standard Model predicts this so-called anomalous magnetic moment extremely precisely. But if the quantum foam contains additional forces or particles not accounted for by the Standard Model, that would tweak the muon g-factor further.
“This quantity we measure reflects the interactions of the muon with everything else in the universe. But when the theorists calculate the same quantity, using all of the known forces and particles in the Standard Model, we don’t get the same answer,” said Renee Fatemi, a physicist at the University of Kentucky and the simulations manager for the Muon g-2 experiment. “This is strong evidence that the muon is sensitive to something that is not in our best theory.”
The predecessor experiment at DOE’s Brookhaven National Laboratory, which concluded in 2001, offered hints that the muon’s behavior disagreed with the Standard Model. The new measurement from the Muon g-2 experiment at Fermilab strongly agrees with the value found at Brookhaven and diverges from theory with the most precise measurement to date.
The first result from the Muon g-2 experiment at Fermilab confirms the result from the experiment performed at Brookhaven National Lab two decades ago. Together, the two results show strong evidence that muons diverge from the Standard Model prediction. Image: Ryan Postel, Fermilab/Muon g-2 collaboration
The accepted theoretical values for the muon are:
g-factor: 2.00233183620(86)
anomalous magnetic moment: 0.00116591810(43)
[uncertainty in parentheses]
The new experimental world-average results announced by the Muon g-2 collaboration today are:
g-factor: 2.00233184122(82)
anomalous magnetic moment: 0.00116592061(41)
The combined results from Fermilab and Brookhaven show a difference with theory at a significance of 4.2 sigma, a little shy of the 5 sigma (or standard deviations) that scientists require to claim a discovery but still compelling evidence of new physics. The chance that the results are a statistical fluctuation is about 1 in 40,000.
The Fermilab experiment reuses the main component from the Brookhaven experiment, a 50-foot-diameter superconducting magnetic storage ring. In 2013, it was transported 3,200 miles by land and sea from Long Island to the Chicago suburbs, where scientists could take advantage of Fermilab’s particle accelerator and produce the most intense beam of muons in the United States. Over the next four years, researchers assembled the experiment; tuned and calibrated an incredibly uniform magnetic field; developed new techniques, instrumentation, and simulations; and thoroughly tested the entire system.
Thousands of people welcomed the Muon g-2 magnet to Fermilab in 2013. Data from the experiment’s first run has yielded a result with unprecedented precision. Data from four additional experimental runs will reveal the muon’s behavior in even more detail. Photo: Reidar Hahn, Fermilab
The Muon g-2 experiment sends a beam of muons into the storage ring, where they circulate thousands of times at nearly the speed of light. Detectors lining the ring allow scientists to determine how fast the muons are precessing.
In its first year of operation, in 2018, the Fermilab experiment collected more data than all prior muon g-factor experiments combined. With more than 200 scientists from 35 institutions in seven countries, the Muon g-2 collaboration has now finished analyzing the motion of more than 8 billion muons from that first run.
“After the 20 years that have passed since the Brookhaven experiment ended, it is so gratifying to finally be resolving this mystery,” said Fermilab scientist Chris Polly, who is a co-spokesperson for the current experiment and was a lead graduate student on the Brookhaven experiment.
Data analysis on the second and third runs of the experiment is under way, the fourth run is ongoing, and a fifth run is planned. Combining the results from all five runs will give scientists an even more precise measurement of the muon’s wobble, revealing with greater certainty whether new physics is hiding within the quantum foam.
“So far we have analyzed less than 6% of the data that the experiment will eventually collect. Although these first results are telling us that there is an intriguing difference with the Standard Model, we will learn much more in the next couple of years,” Polly said.
“Pinning down the subtle behavior of muons is a remarkable achievement that will guide the search for physics beyond the Standard Model for years to come,” said Fermilab Deputy Director of Research Joe Lykken. “This is an exciting time for particle physics research, and Fermilab is at the forefront.”
Press release from the Fermilab; first results from Fermilab’s Muon g-2 experiment strengthen evidence of new physics.
