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ST/ Star dancing around supermassive black hole proves Einstein right

Paradigm
Paradigm
Published in
28 min readApr 23, 2020

Space biweekly, 9th April — 23rd April

TL;DR

Space industry in numbers

Last summer, the Space Foundation published the second-quarter findings of its 2019 issue of The Space Report, revealing that:

  • The global space economy grew 8.1% in 2018 to USA 414.75 billion, exceeding USD 400 billion for the first time.
  • Global launches in 2018 increased by 46% over the number of launches a decade ago.
  • Global launches in 2018 exceeded 100 for the first time since 1990.

Analysts at Morgan Stanley and Goldman Sachs have predicted that economic activity in space will become a multi-trillion-dollar market in the coming decades. Morgan Stanley’s Space Team estimates that the roughly USD 350 billion global space industry could surge to over USD 1 trillion by 2040.

Source: Satellite Industry Association, Morgan Stanley Research, Thomson Reuters. *2040 estimates

Space industry news

CHEOPS space telescope ready for scientific operation: CHEOPS has reached its next milestone: Following extensive tests in Earth’s orbit, some of which the mission team was forced to carry out from home due to the coronavirus crisis, the space telescope has been declared ready for science. CHEOPS stands for ‘’CHaracterising ExOPlanet Satellite’’, and has the purpose of investigating known exoplanets to determine, among other things, whether they have conditions that are hospitable to life.

Russia’s rocket man set for return to virus-plagued planet: Covid-19 was unheard of when Commander of International Space Station left earth.

Exolaunch signs first launch agreement with SpaceX: German launch services provider Exolaunch announced plans April 14 to send multiple small satellites into orbit on a SpaceX Falcon 9 rideshare mission scheduled for December.

Falcon 9 launches 60 Starlink satellites to orbit, completing this booster’s fourth flight:

NASA sets May 27 launch date for SpaceX commercial crew test flight:

STScI, NASA, ESA, and CSA have decided to further delay the schedule for JWST Cycle 1 GO/AR proposals due to disruptions from COVID-19:

More news

Researchers

Genomic mapping in outbred mice reveals overlap in genetic susceptibility for HZE ion– and γ-ray–induced tumors by E. F. Edmondson, D. M. Gatti, F. A. Ray, E. L. Garcia, C. M. Fallgren, D. A. Kamstock and M. M. Weil in Science Advances:

NASA, aims to send human missions to Mars in the 2030s. But scientists are still trying to learn more about the potential cancer risks for astronauts due to radiation exposure. Cancer risk from galactic cosmic radiation exposure is considered a potential “showstopper” for a manned mission to Mars.

Wireless Power Transmission Efficiency for Microwave Rocket Using 28 GHz Gyrotron by Kohei Shimamura, Maho Matsukura, Naoto Ozaki, Kaisei Miyawaki, Shigeru Yokota, Ryutaro Minami, Tsuyoshi Kariya, Tsuyoshi Imai in Journal of Spacecraft and Rockets:

Governments throughout the world use rockets to launch satellites and people into orbit. This currently requires a lot of high-energy fuel, which is 95% of total rocket mass. Because the launch cost of a rocket can reach 10 billion yen, launching a 1-gram payload is said to be the same as buying 1 gram of gold. Minimizing the total cost of launching rockets would maximize the scientific payloads and increase the feasibility of space exploration.

Space exploration and cosmology news

New comprehensive geologic map of the Moon released

The lunar map, called the “Unified Geologic Map of the Moon,” will serve as the definitive blueprint of the moon’s surface geology for future human missions and will be invaluable for the international scientific community, educators and the public-at-large. The digital map is available online now and shows the moon’s geology in incredible detail (1:5,000,000 scale).

To create the new digital map, scientists used information from six Apollo-era regional maps along with updated information from recent satellite missions to the moon. The existing historical maps were redrawn to align them with the modern data sets, thus preserving previous observations and interpretations. Along with merging new and old data, USGS researchers also developed a unified description of the stratigraphy, or rock layers, of the moon. This resolved issues from previous maps where rock names, descriptions and ages were sometimes inconsistent.

Orthographic projections of the “Unified Geologic Map of the Moon” showing the geology of the Moon’s near side (left) and far side (right) with shaded topography from the Lunar Orbiter Laser Altimeter (LOLA). This geologic map is a synthesis of six Apollo-era regional geologic maps, updated based on data from recent satellite missions. It will serve as a reference for lunar science and future human missions to the Moon. Credit: NASA/GSFC/USGS.

GW190412: Observation of a Binary-Black-Hole Coalescence with Asymmetric Masses

Scientists detect rare crash of two mismatched black holes for the first time ever

On April 12, 2019, gravitational wave detectors picked up a signal of space-time ripples caused by colliding black holes — which in and of itself has gone from groundbreaking to nearly mundane over the past five years. But as scientists studied the detection more closely, they realized that it didn’t match the signals they have seen so far.

Instead of two evenly matched black holes, the new detection seemed to be triggered by a lopsided merger in which one black hole was three or four times more massive than the other. Scientists affiliated with the Laser Interferometer Gravitational-wave Observatory (LIGO) announced the discovery April 18 at an online meeting of the American Physical Society.

“It’s an unlikely observation,” Maya Fishbach, a doctoral candidate at the University of Chicago who presented the new discovery, said during her talk. “It’s an exceptional event because we just wouldn’t have expected it based on those first 10 binary black holes.”

An artist’s depiction of mismatched black holes colliding. (Image credit: N. Fischer, H. Pfeiffer, A. Buonanno (Max Planck Institute for Gravitational Physics), Simulating eXtreme Spacetimes project)

Scientists studied those 10 mergers during LIGO’s first two observing runs, conducted between 2015 and 2017. Each time, no matter how big the collision, the two black holes involved were about the same size. Then, just weeks into LIGO’s third observing run in 2019, the newly reported signal appeared and turned that trend on its head.

“We had detected several binary black hole mergers before, but never one where the bigger black hole is nearly four times more massive than its companion,” Frank Ohme, a LIGO scientist at the Max Planck Institute for Gravitational Physics in Germany, said in a statement. “It’s clear we are just beginning to understand the diversity of black hole binaries out there, and I am excited to decipher the universe’s secrets every day a little more.”

The newly announced discovery involved objects about 2.4 billion light-years away, Fishbach said, with one black hole about eight times the mass of our sun and the other about 30 times the mass of our sun.

“This is roughly equal to the ratio of filling in a regular Oreo to [that] in a Mega Stuf Oreo,” Christopher Berry, a gravitational-wave scientist at Northwestern University, wrote in a blog post about the detection. (Don’t get too excited: “Investigations of connections between Oreos and black hole formation are ongoing,” he added.)

The detection gives scientists a better understanding of how black holes pair up. “We are learning that systems of this kind exist and how rare they are,” Giancarlo Cella, researcher at Istituto Nazionale di Fisica Nucleare in Italy and the data analysis coordinator for LIGO’s European counterpart Virgo, said in a statement. “This will allow us to deduce how they formed.”

LIGO’s third observing run, which was cut short by the spreading coronavirus pandemic, netted a treasure trove of more than 50 detections, Fishbach said. Scientists are still analyzing those observations, so other unbalanced mergers could be hiding in that data. But even just the one asymmetric merger dramatically reshapes the range of black hole pairs scientists are now prepared to expect.

Detection of the Schwarzschild precession in the orbit of the star S2 near the Galactic centre massive black hole

by GRAVITY Collaboration in Astronomy & Astrophysics

Observations made with ESO’s Very Large Telescope (VLT) have revealed for the first time that a star orbiting the supermassive black hole at the centre of the Milky Way moves just as predicted by Einstein’s general theory of relativity. Its orbit is shaped like a rosette and not like an ellipse as predicted by Newton’s theory of gravity. This long-sought-after result was made possible by increasingly precise measurements over nearly 30 years, which have enabled scientists to unlock the mysteries of the behemoth lurking at the heart of our galaxy.

The star S2 orbiting the compact radio source Sgr A* is a precision probe of the gravitational field around the closest massive black hole (candidate). Over the last 2.7 decades researchers have monitored the star’s radial velocity and motion on the sky, mainly with the SINFONI and NACO adaptive optics (AO) instruments on the ESO VLT, and since 2017, with the four-telescope interferometric beam combiner instrument GRAVITY. They report the first detection of the General Relativity (GR) Schwarzschild Precession (SP) in S2’s orbit. Owing to its highly elliptical orbit (e = 0.88), S2’s SP is mainly a kink between the pre-and post-pericentre directions of motion ≈±1 year around pericentre passage, relative to the corresponding Kepler orbit. The superb 2017−2019 astrometry of GRAVITY defines the pericentre passage and outgoing direction. The incoming direction is anchored by 118 NACO-AO measurements of S2’s position in the infrared reference frame, with an additional 75 direct measurements of the S2-Sgr A* separation during bright states (“flares”) of Sgr A*. The 14-parameter model fits for the distance, central mass, the position and motion of the reference frame of the AO astrometry relative to the mass, the six parameters of the orbit, as well as a dimensionless parameter fSP for the SP (fSP = 0 for Newton and 1 for GR). From data up to the end of 2019 they robustly detect the SP of S2, δϕ ≈ 12′ per orbital period. From posterior fitting and MCMC Bayesian analysis with different weighting schemes and bootstrapping scientists find fSP = 1.10 ± 0.19. The S2 data are fully consistent with GR. Any extended mass inside S2’s orbit cannot exceed ≈0.1% of the central mass. Any compact third mass inside the central arcsecond must be less than about 1000 M⊙.

The VLT’s Laser Guide Star

“Einstein’s General Relativity predicts that bound orbits of one object around another are not closed, as in Newtonian Gravity, but precess forwards in the plane of motion. This famous effect — first seen in the orbit of the planet Mercury around the Sun — was the first evidence in favour of General Relativity. One hundred years later we have now detected the same effect in the motion of a star orbiting the compact radio source Sagittarius A* at the centre of the Milky Way. This observational breakthrough strengthens the evidence that Sagittarius A* must be a supermassive black hole of 4 million times the mass of the Sun,” says Reinhard Genzel, Director at the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, Germany and the architect of the 30-year-long programme that led to this result.

A Habitable-zone Earth-sized Planet Rescued from False Positive Status

by Andrew Vanderburg, Pamela Rowden, Steve Bryson, Jeffrey Coughlin, Natalie Batalha, Karen A. Collins, David W. Latham, Susan E. Mullally, Knicole D. Colón, Chris Henze, Chelsea X. Huang, Samuel N. Quinn by The Astrophysical Journal

A reanalysis of data from NASA’s Kepler space telescope has revealed an Earth-size exoplanet orbiting in its star’s habitable zone, the area around a star where a rocky planet could support liquid water.

Researchers report the discovery of an Earth-sized planet in the habitable zone of a low-mass star called Kepler-1649. The planet, Kepler-1649 c, is 1.06${}_{-0.10}^{+0.15}$ times the size of Earth and transits its 0.1977 ± 0.0051 ${M}_{\odot }$ “mid” M-dwarf host star every 19.5 days. It receives 74% ± 3% the incident flux of Earth, giving it an equilibrium temperature of 234 ± 20 K and placing it firmly inside the circumstellar habitable zone. Kepler-1649 also hosts a previously known inner planet that orbits every 8.7 days and is roughly equivalent to Venus in size and incident flux. Kepler-1649 c was originally classified as a false positive (FP) by the Kepler pipeline, but was rescued as part of a systematic visual inspection of all automatically dispositioned Kepler FPs. This discovery highlights the value of human inspection of planet candidates even as automated techniques improve, and hints that terrestrial planets around mid to late M-dwarfs may be more common than those around more massive stars.

“This intriguing, distant world gives us even greater hope that a second Earth lies among the stars, waiting to be found,” said Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate in Washington. “The data gathered by missions like Kepler and our Transiting Exoplanet Survey Satellite [TESS] will continue to yield amazing discoveries as the science community refines its abilities to look for promising planets year after year.”

New HST data and modeling reveal a massive planetesimal collision around Fomalhaut

by András Gáspár, George H. Rieke in Proceedings of the National Academy of Sciences

What scientists thought was a planet beyond our solar system has ‘vanished.’ Though this happens to sci-fi worlds, scientists seek a more plausible explanation. One interpretation: instead of a planet, it could be a dust cloud produced by two large bodies colliding.

Although originally thought to be a massive exoplanet, the faintness of Fomalhaut b in the infrared and its failure to perturb Fomalhaut’s debris ring indicate a low mass. We use all available data to reveal that it has faded in brightness and grown in extent, with motion consistent with an escaping orbit. This behavior confirms suggestions that the source is a dispersing cloud of dust, produced by a massive collision between two planetesimals. The visible signature appears to be very fine dust escaping under the influence of radiation pressure. Such events should be rare in quiescent planetary systems at the age of Fomalhaut, suggesting increased dynamical activity within the system possibly due to orbital migration of hypothetical planets.

The apparent detection of an exoplanet orbiting Fomalhaut was announced in 2008. However, subsequent observations of Fomalhaut b raised questions about its status: Unlike other exoplanets, it is bright in the optical and nondetected in the infrared, and its orbit appears to cross the debris ring around the star without the expected gravitational perturbations. Researchers revisit previously published data and analyze additional Hubble Space Telescope (HST) data, finding that the source is likely on a radial trajectory and has faded and become extended. Dynamical and collisional modeling of a recently produced dust cloud yields results consistent with the observations. Fomalhaut b appears to be a directly imaged catastrophic collision between two large planetesimals in an extrasolar planetary system. Similar events should be very rare in quiescent planetary systems of the age of Fomalhaut, suggesting that they are possibly witnessing the effects of gravitational stirring due to the orbital evolution of hypothetical planet(s) around the star.

Stars made in outflows may populate the stellar halo of the Milky Way

by Claude-André Faucher-Giguère, Dušan Kereš, Philip F. Hopkins, Michael Y. Grudić, Anna M. Nierenberg, Michael Boylan-Kolchin, Andrew S. Graus, Robyn E. Sanderson, Andrew Wetzel, James S. Bullock, Sijie Yu in Monthly Notices of the Royal Astronomical Society

A simulated galaxy image from the FIRE-2 project, representing a structure spanning more than 200,000 light years, shows the prominent plumes of young blue stars born in gas that was originally rotating and then blown radially outward by supernova explosions. Courtesy of Sijie Yu / UCI

Though mighty, the Milky Way and galaxies of similar mass are not without scars chronicling turbulent histories. University of California, Irvine astronomers and others have shown that clusters of supernovas can cause the birth of scattered, eccentrically orbiting suns in outer stellar halos, upending commonly held notions of how star systems have formed and evolved over billions of years.

Hyper-realistic, cosmologically self-consistent computer simulations from the Feedback in Realistic Environments 2 project enabled the scientists to model the disruptions in otherwise orderly galactic rotations. The team’s work is the subject of a study published today in the Monthly Notices of the Royal Astronomical Society.

This mock Hubble Space Telescope image shows how star formation happens at the edges of a supernova bubble. The portion highlighted in pink shows the stellar birth region. Blue shaded areas show young stars; red/brown shows where dust has obscured the starlight. The simulation shows clearly where stellar outflow shells are being generated. Courtesy of Sijie Yu / UCI

“These highly accurate numerical simulations have shown us that it’s likely the Milky Way has been launching stars in circumgalactic space in outflows triggered by supernova explosions,” said senior author James Bullock, dean of UCI’s School of Physical Sciences and a professor of physics & astronomy. “It’s fascinating, because when multiple big stars die, the resulting energy can expel gas from the galaxy, which in turn cools, causing new stars to be born.”

Bullock said the diffuse distribution of stars in the stellar halo that extends far outside the classical disk of a galaxy is where the “archeological record” of the system exists. Astronomers have long assumed that galaxies are assembled over lengthy periods of time as smaller star groupings come in and are dismembered by the larger body, a process that ejects some stars into distant orbits. But the UCI team is proposing “supernova feedback” as a different source for as many as 40 percent of these outer-halo stars.

Lead author Sijie Yu, a UCI Ph.D. candidate in physics, said the findings were made possible partly by the availability of a powerful new set of tools.

“The FIRE-2 simulations allow us to generate movies that make it seem as though you’re observing a real galaxy,” she noted. “They show us that as the galaxy center is rotating, a bubble driven by supernova feedback is developing with stars forming at its edge. It looks as though the stars are being kicked out from the center.”

Bullock said he did not expect to see such an arrangement because stars are such tight, incredibly dense balls that are generally not subject to being moved relative to the background of space. “Instead, what we’re witnessing is gas being pushed around,” he said, “and that gas subsequently cools and makes stars on its way out.”

The researchers said that while their conclusions have been drawn from simulations of galaxies forming, growing and evolving to the present day, there is actually a fair amount of observational evidence that stars are forming in outflows from galactic centers to their halos.

“In plots that compare data from the European Space Agency’s Gaia mission — which provides a 3D velocity chart of stars in the Milky Way — with other maps that show stellar density and metallicity, we can see structures similar to those produced by outflow stars in our simulations,” Yu said.

Bullock added that mature, heavier, metal-rich stars like our sun rotate around the center of the galaxy at a predictable speed and trajectory. But the low-metallicity stars, which have been subjected to fewer generations of fusion than our sun, can be seen rotating in the opposite direction.

He said that over the lifespan of a galaxy, the number of stars produced in supernova bubble outflows is small, around 2 percent. But during the parts of galaxies’ histories when starburst events are booming, as many as 20 percent of stars are being formed this way.

The carbon monoxide-rich interstellar comet 2I/Borisov

by D. Bodewits, J. W. Noonan, P. D. Feldman, M. T. Bannister, D. Farnocchia, W. M. Harris, J.-Y. Li, K. E. Mandt, J. Wm. Parker & Z.-X. Xing in Nature Astronomy

Hubble Space Telescope data show that interstellar comet 2I/Borisov has an unusually high CO/H2O ratio — higher than any other comet that has been seen in the inner regions of our Solar System. This allows us to constrain the nature and location of the circumstellar region from which 2I/Borisov originated.

Interstellar comets offer direct samples of volatiles from distant protoplanetary disks. 2I/Borisov is the first notably active interstellar comet discovered in our Solar System. Comets are condensed samples of the gas, ice and dust that were in a star’s protoplanetary disk during the formation of its planets, and inform our understanding on how chemical compositions and abundances vary with distance from the central star. Their orbital migration distributes volatiles, organic material and prebiotic chemicals around their host system. In our Solar System, hundreds of comets have been observed remotely, and a few have been studied up close by space missions. However, knowledge of extrasolar comets has been limited to what could be gleaned from distant, unresolved observations of cometary regions around other stars, with only one detection of carbon monoxide. Scientists report that the coma of 2I/Borisov contains substantially more CO than H2O gas, with abundances of at least 173%, more than three times higher than previously measured for any comet in the inner (<2.5 au) Solar System4. Their ultraviolet Hubble Space Telescope observations of 2I/Borisov provide the first glimpse into the ice content and chemical composition of the protoplanetary disk of another star that is substantially different from our own.

Unusually high CO abundance of the first active interstellar comet

by M. A. Cordiner, S. N. Milam, N. Biver, D. Bockelée-Morvan, N. X. Roth, E. A. Bergin, E. Jehin, A. J. Remijan, S. B. Charnley, M. J. Mumma, J. Boissier, J. Crovisier, L. Paganini, Y.-J. Kuan & D. C. Lis in Nature Astronomy

A galactic visitor entered our solar system last year — interstellar comet 2I/Borisov. When astronomers pointed the Atacama Large Millimeter/submillimeter Array (ALMA) toward the comet on Dec. 15–16, 2019, for the first time they directly observed the chemicals stored inside an object from a planetary system other than our own.

Comets spend most of their lives at large distances from any star, during which time their interior compositions remain relatively unaltered. Cometary observations can therefore provide direct insight into the chemistry that occurred during their birth at the time of planet formation. To date, there have been no confirmed observations of parent volatiles (gases released directly from the nucleus) of a comet from any planetary system other than our own. Researchers present high-resolution interferometric observations of 2I/Borisov, the first confirmed interstellar comet, obtained using the Atacama Large Millimeter/submillimeter Array (ALMA) on 15–16 December 2019. Their observations reveal emission from hydrogen cyanide (HCN) and carbon monoxide (CO) coincident with the expected position of 2I/Borisov’s nucleus, with production rates Q(HCN) = (7.0 ± 1.1) × 1023 s−1 and Q(CO) = (4.4 ± 0.7) × 1026 s−1. While the HCN abundance relative to water (0.06–0.16%) appears similar to that of typical, previously observed comets in our Solar System, the abundance of CO (35–105%) is among the highest observed in any comet within 2 au of the Sun. This shows that 2I/Borisov must have formed in a relatively CO-rich environment — probably beyond the CO ice-line in the very cold, outer regions of a distant protoplanetary accretion disk, as part of a population of small icy bodies analogous to our Solar System’s own proto-Kuiper belt.

Histogram showing previously published CO/HCN mixing ratios observed in Solar System comets. Twenty-four Oort Cloud comets and three Jupiter-family comets are shown. The unusually high CO/HCN ratio of 2I/Borisov (630+200−340) is highlighted, along with the chemically peculiar outlier C/2016 R2 (PanSTARRS), which had CO/HCN=26,400. Horizontal black bar indicates the uncertainty range of the analysis.

Tidal fragmentation as the origin of 1I/2017 U1 (‘Oumuamua)

by Yun Zhang & Douglas N. C. Lin in Nature Astronomy

Since its discovery in 2017, an air of mystery has surrounded the first known interstellar object to visit our solar system, an elongated, cigar-shaped body named ‘Oumuamua (Hawaiian for “a messenger from afar arriving first”).

The first discovered interstellar object (ISO), ‘Oumuamua (1I/2017 U1) shows a dry and rocky surface, an unusually elongated shape, with short-to-long axis ratio c∕a ≲ 1∕6, a low velocity relative to the local standard of rest (~10 km s−1), non-gravitational accelerations and tumbles on a timescale of a few hours. The inferred number density (~3.5 × 1013−2 × 1015 pc−3) for a population of asteroidal ISOs outnumbers cometary ISOs by ≥103, in contrast to the much lower ratio (≲10−2) of rocky/icy Kuiper belt objects. Although some scenarios can cause the ejection of asteroidal ISOs, a unified formation theory has yet to comprehensively link all ‘Oumuamua’s puzzling characteristics and to account for the population. Researchers show by numerical simulations that ‘Oumuamua-like ISOs can be prolifically produced through extensive tidal fragmentation and ejected during close encounters of their volatile-rich parent bodies with their host stars. Material strength enhanced by the intensive heating during periastron passages enables the emergence of extremely elongated triaxial ISOs with shape c∕a ≲ 1∕10, sizes a ≈ 100 m and rocky surfaces. Although volatiles with low sublimation temperature (such as CO) are concurrently depleted, H2O buried under surfaces is preserved in these ISOs, providing an outgassing source without measurable cometary activities for ‘Oumuamua’s non-gravitational accelerations during its passage through the inner Solar System. They infer that the progenitors of ‘Oumuamua-like ISOs may be kilometre-sized long-period comets from Oort clouds, kilometre-sized residual planetesimals from debris disks or planet-sized bodies at a few astronomical units, orbiting around low-mass main-sequence stars or white dwarfs. These provide abundant reservoirs to account for ‘Oumuamua’s occurrence rate.

Large H2O solubility in dense silica and its implications for the interiors of water-rich planets

by Carole Nisr, Huawei Chen, Kurt Leinenweber, Andrew Chizmeshya, Vitali B. Prakapenka, Clemens Prescher, Sergey N. Tkachev, Yue Meng, Zhenxian Liu, and Sang-Heon Shim

In seeking to learn more about Neptune-like exoplanets, an international team of researchers has provided one of the first mineralogy lab studies for water-rich exoplanets

Astrophysical observations have shown that Neptune-like planets are common in our galaxy (sub-Neptunes). Some of these exoplanets are believed to be covered with a thick H2O layer (100 to 1,000 km in thickness) above the rocky mantle (“waterworlds”). In order to understand the inner workings of the water-rich planets, it is important to understand the state of matter incorporating ice- and rock-forming elements at high-pressure and high-temperature conditions. Researchers report experimental evidence that silica and water have significant mutual solubility at high pressure and high temperature, forming new phases containing substantial amounts of both H and Si in oxide forms. Therefore, the boundary between rock and ice layers may be “fuzzy” at the deep interiors of water-rich planets.

Sub-Neptunes are common among the discovered exoplanets. However, lack of knowledge on the state of matter in H2O-rich setting at high pressures and temperatures (P−T) places important limitations on our understanding of this planet type. Scientists have conducted experiments for reactions between SiO2 and H2O as archetypal materials for rock and ice, respectively, at high P−T. They found anomalously expanded volumes of dense silica (up to 4%) recovered from hydrothermal synthesis above ∼24 GPa where the CaCl2-type (Ct) structure appears at lower pressures than in the anhydrous system. Infrared spectroscopy identified strong OH modes from the dense silica samples. Both previous experiments and our density functional theory calculations support up to 0.48 hydrogen atoms per formula unit of (Si1−xH4x)O2 (x=0.12). At pressures above 60 GPa, H2O further changes the structural behavior of silica, stabilizing a niccolite-type structure, which is unquenchable. From unit-cell volume and phase equilibrium considerations, we infer that the niccolite-type phase may contain H with an amount at least comparable with or higher than that of the Ct phase. The results suggest that the phases containing both hydrogen and lithophile elements could be the dominant materials in the interiors of water-rich planets. Even for fully layered cases, the large mutual solubility could make the boundary between rock and ice layers fuzzy. Therefore, the physical properties of the new phases that researchers report here would be important for understanding dynamics, geochemical cycle, and dynamo generation in water-rich planets.

Constraint on the matter–antimatter symmetry-violating phase in neutrino oscillations

by The T2K Collaboration in Nature

New data throws more support behind the theory that neutrinos are the reason the universe is dominated by matter

The charge-conjugation and parity-reversal (CP) symmetry of fundamental particles is a symmetry between matter and antimatter. Violation of this CP symmetry was first observed in 1964, and CP violation in the weak interactions of quarks was soon established. Sakharov proposed that CP violation is necessary to explain the observed imbalance of matter and antimatter abundance in the Universe. However, CP violation in quarks is too small to support this explanation. So far, CP violation has not been observed in non-quark elementary particle systems. It has been shown that CP violation in leptons could generate the matter–antimatter disparity through a process called leptogenesis. Leptonic mixing, which appears in the standard model’s charged current interactions, provides a potential source of CP violation through a complex phase δCP, which is required by some theoretical models of leptogenesis. This CP violation can be measured in muon neutrino to electron neutrino oscillations and the corresponding antineutrino oscillations, which are experimentally accessible using accelerator-produced beams as established by the Tokai-to-Kamioka (T2K) and NOvA experiments. Until now, the value of δCP has not been substantially constrained by neutrino oscillation experiments. Researchers report a measurement using long-baseline neutrino and antineutrino oscillations observed by the T2K experiment that shows a large increase in the neutrino oscillation probability, excluding values of δCP that result in a large increase in the observed antineutrino oscillation probability at three standard deviations (3σ). The 3σ confidence interval for δCP, which is cyclic and repeats every 2π, is [−3.41, −0.03] for the so-called normal mass ordering and [−2.54, −0.32] for the inverted mass ordering. Their results indicate CP violation in leptons and their method enables sensitive searches for matter–antimatter asymmetry in neutrino oscillations using accelerator-produced neutrino beams. Future measurements with larger datasets will test whether leptonic CP violation is larger than the CP violation in quarks.

The available data also strongly discount the possibility that neutrinos and antineutrinos are as just likely as each other to change flavour. Dr Patrick Dunne, from the Department of Physics at Imperial, said:

“What our result shows is that we’re more than 95 per cent sure that matter neutrinos and antineutrinos behave differently. This is big news in itself; however we do already know of other particles that have matter-antimatter differences that are too small to explain our matter-dominated universe.

Therefore, measuring the size of the difference is what matters for determining whether neutrinos can answer this fundamental question. Our result today finds that unlike for other particles, the result in neutrinos is compatible with many of the theories explaining the origin of the universe’s matter dominance.”

Discovery of a Remarkably Powerful Broad Absorption-line Quasar Outflow in SDSS J135246.37+423923.5

by Hyunseop Choi, Karen M. Leighly, Donald M. Terndruph, Sarah C. Gallagher, and Gordon T. Richards in The Astrophysical Journal

Researchers using the Gemini North telescope on Hawai’i’s Maunakea have detected the most energetic wind from any quasar ever measured. This outflow, which is travelling at nearly 13% of the speed of light, carries enough energy to dramatically impact star formation across an entire galaxy. The extragalactic tempest lay hidden in plain sight for 15 years before being unveiled by innovative computer modeling and new data from the international Gemini Observatory.

The most energetic wind from a quasar has been revealed by a team of astronomers using observations from the international Gemini Observatory, a program of NSF’s NOIRLab. This powerful outflow is moving into its host galaxy at almost 13% of the speed of light, and stems from a quasar known as SDSS J135246.37+423923.5 which lies roughly 60 billion light-years from Earth.

“While high-velocity winds have previously been observed in quasars, these have been thin and wispy, carrying only a relatively small amount of mass,” explains Sarah Gallagher, an astronomer at Western University (Canada) who led the Gemini observations. “The outflow from this quasar, in comparison, sweeps along a tremendous amount of mass at incredible speeds. This wind is crazy powerful, and we don’t know how the quasar can launch something so substantial.”

As well as measuring the outflow from SDSS J135246.37+423923.5, the team was also able to infer the mass of the supermassive black hole powering the quasar. This monstrous object is 8.6 billion times as massive as the Sun -about 2000 times the mass of the black hole in the center of our Milky Way and 50% more massive than the well-known black hole in the galaxy Messier 87.

Despite its mass and energetic outflow, the discovery of this powerhouse languished in a quasar survey for 15 years before the combination of Gemini data and the team’s innovative computer modeling method allowed it to be studied in detail.

Electron temperature of the solar wind

by Stanislav Boldyrev, Cary Forest, Jan Egedal in Proceedings of the National Academy of Sciences

When the sun expels plasma, the solar wind cools as it expands through space — but not as much as the laws of physics would predict. Physicists now know the reason

The problem of solar wind heating is one of the long-standing fundamental problems of space plasma physics. Researchers propose that the electron component of the solar wind plasma is heated by electrons streaming from the hot solar corona and slowly losing their energy due to weak Coulomb collisions. Their first-principle kinetic derivation predicts the scaling of the solar wind electron temperature with the heliocentric distance, which is in good agreement with observations. Recearcher’s theory reveals the role of the non-Maxwellian electron distribution function in the heating mechanism, and it may be valuable for interpreting the results of in situ satellite measurements.

“In the solar wind, the hot electrons stream from the sun to very large distances, losing their energy very slowly and distributing it to the trapped population,” Boldyrev says. “It turns out that our results agree very well with measurements of the temperature profile of the solar wind and they may explain why the electron temperature declines with the distance so slowly,” Stas Boldyrev, professor of physics and lead author of the study, says.

Chemically distinct regions of Venus’s atmosphere revealed by measured N2 concentrations: A MESSENGER flyby of Venus has detected a difference in N2 composition between the upper and lower atmosphere. The presence of substantially distinct regions within Venus’s atmosphere has implications on remote sensing techniques for exoplanets.

Spitzer’s debris disk legacy from main-sequence stars to white dwarfs: The Spitzer Space Telescope made huge advances in the study of debris disks around main-sequence stars and white dwarfs, increasing their number by an order of magnitude, and leading the way for the next generation of space-based infrared missions.

An extremely energetic supernova from a very massive star in a dense medium: A recent supernova event, SN2016aps, must have involved an extremely energetic explosion and a very massive star, potentially indicating a pair-instability supernova or pulsational pair-instability supernova mechanism.

Direct evidence for shock-powered optical emission in a nova: Simultaneous optical and gamma-ray observations of nova V906 Carinae reveal correlated flares in both wavelength ranges that can be linked to shocks in the nova ejecta. Weak X-ray emission suggests that the shocks are deeply embedded, but they contribute substantially to the luminosity of the nova.

MISC

Tour the cosmos with #NASAatHome Sparkles: Travel into deep space with their 3D interactive application in search of strange & unusual planets that lurk beyond our solar system — called exoplanets.

The discovery of cosmic fullerenes: In 2010, the Spitzer Space Telescope detected evidence of a complex form of carbon that had never been seen in extraterrestrial environments. Jan Cami recounts the discovery of buckminsterfullerene in space.

Tickling the Asteroid’s Tail: How do you return a piece of asteroid to Earth? Practice.

Coronavirus quarantine could provide lessons for future space travel on how regular people weather isolation: Understanding isolation’s effects on regular people, rather than those certified to have ‘the right stuff,’ will help prepare us for the future, whether another pandemic or interplanetary space travel.

Giant leap for corporations? The Trump administration wants to mine resources in space, but is it legal?: Governments and corporations must get serious about the legal, technical, economic, social and ethical implications of a potential space-based resource economy.

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