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Flyaway

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New nova in Cassiopeia brightens rapidly

There’s a ‘new star’ – a classical nova – on show among the stars of the far-northern constellation of Cassiopeia. Nova Cas 2021 was discovered on 18 March shining at around magnitude +9.6, but it appears to have brightened rapidly to around magnitude +7.5 on 19 March.

Nova Cas 2021 was discovered by Yuji Nakamura of Japan on 18 March at about 10h UT, when it shone at around magnitude +9.6. He shot four 15-second frames with a 135mm, f/4 lens coupled to a CCD camera (a set-up which provided a limiting magnitude of +12) and further reported that no object was seen at the transient object’s position on frames shot with the same equipment on 14 March.

Just hours later, professional astronomers from the National Astronomical Observatory of Japan swung into action, obtaining a spectrum of the object with the 3.8-m Seimei Telescope at Okayama Observatory and photometry through a 0.4-m telescope at Kyoto University. The spectrum revealed the tell tale features of a classical nova, with emission lines of the Balmer series, N-III 4640 and He-II 4686, and He-I emission lines with P-Cyg profiles. They further found and identified lines N-II 5679, C-III 5695 and Paschen emission lines. The position of Nova Cas 2021 precisely coincides with that of the W UMa-type eclipsing variable star CzeV3217, which lies at a distance of about 5,500 light years.

 

Flyaway

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A Restless Supermassive Black Hole in the Galaxy J0437+2456

Abstract
We present the results from an observing campaign to confirm the peculiar motion of the supermassive black hole (SMBH) in J0437+2456 first reported in Pesce et al. Deep observations with the Arecibo Observatory have yielded a detection of neutral hydrogen (H i) emission, from which we measure a recession velocity of 4910 km s−1 for the galaxy as a whole. We have also obtained near-infrared integral field spectroscopic observations of the galactic nucleus with the Gemini North telescope, yielding spatially resolved stellar and gas kinematics with a central velocity at the innermost radii (0farcs1 ≈ 34 pc) of 4860 km s−1. Both measurements differ significantly from the ~4810 km s−1 H2O megamaser velocity of the SMBH, supporting the prior indications of a velocity offset between the SMBH and its host galaxy. However, the two measurements also differ significantly from one another, and the galaxy as a whole exhibits a complex velocity structure that implies that the system has recently been dynamically disturbed. These results make it clear that the SMBH is not at rest with respect to the systemic velocity of the galaxy, though the specific nature of the mobile SMBH—i.e., whether it traces an ongoing galaxy merger, a binary black hole system, or a gravitational-wave recoil event—remains unclear.


 

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Test of lepton universality in beauty-quark decays

The Standard Model of particle physics currently provides our best description of fundamental particles and their interactions. The theory predicts that the different charged leptons, the electron, muon and tau, have identical electroweak interaction strengths. Previous measurements have shown a wide range of particle decays are consistent with this principle of lepton universality. This article presents evidence for the breaking of lepton universality in beauty-quark decays, with a significance of 3.1 standard deviations, based on proton-proton collision data collected with the LHCb detector at CERN's Large Hadron Collider. The measurements are of processes in which a beauty meson transforms into a strange meson with the emission of either an electron and a positron, or a muon and an antimuon. If confirmed by future measurements, this violation of lepton universality would imply physics beyond the Standard Model, such as a new fundamental interaction between quarks and leptons.

 

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View: https://youtu.be/DzZ5mb0SD2E

ESO Press Release:

Astronomers image magnetic fields at the edge of M87’s black hole

 
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Flyaway

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First M87 Event Horizon Telescope Results. VII. Polarization of the Ring

Abstract
In 2017 April, the Event Horizon Telescope (EHT) observed the near-horizon region around the supermassive black hole at the core of the M87 galaxy. These 1.3 mm wavelength observations revealed a compact asymmetric ring-like source morphology. This structure originates from synchrotron emission produced by relativistic plasma located in the immediate vicinity of the black hole. Here we present the corresponding linear-polarimetric EHT images of the center of M87. We find that only a part of the ring is significantly polarized. The resolved fractional linear polarization has a maximum located in the southwest part of the ring, where it rises to the level of ~15%. The polarization position angles are arranged in a nearly azimuthal pattern. We perform quantitative measurements of relevant polarimetric properties of the compact emission and find evidence for the temporal evolution of the polarized source structure over one week of EHT observations. The details of the polarimetric data reduction and calibration methodology are provided. We carry out the data analysis using multiple independent imaging and modeling techniques, each of which is validated against a suite of synthetic data sets. The gross polarimetric structure and its apparent evolution with time are insensitive to the method used to reconstruct the image. These polarimetric images carry information about the structure of the magnetic fields responsible for the synchrotron emission. Their physical interpretation is discussed in an accompanying publication.

 

Flyaway

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First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near The Event Horizon

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Event Horizon Telescope (EHT) observations at 230 GHz have now imaged polarized emission around the supermassive black hole in M87 on event-horizon scales. This polarized synchrotron radiation probes the structure of magnetic fields and the plasma properties near the black hole. Here we compare the resolved polarization structure observed by the EHT, along with simultaneous unresolved observations with the Atacama Large Millimeter/submillimeter Array, to expectations from theoretical models. The low fractional linear polarization in the resolved image suggests that the polarization is scrambled on scales smaller than the EHT beam, which we attribute to Faraday rotation internal to the emission region. We estimate the average density ne ~ 104–7 cm−3, magnetic field strength B ~ 1–30 G, and electron temperature Te ~ (1–12) × 1010 K of the radiating plasma in a simple one-zone emission model. We show that the net azimuthal linear polarization pattern may result from organized, poloidal magnetic fields in the emission region. In a quantitative comparison with a large library of simulated polarimetric images from general relativistic magnetohydrodynamic (GRMHD) simulations, we identify a subset of physical models that can explain critical features of the polarimetric EHT observations while producing a relativistic jet of sufficient power. The consistent GRMHD models are all of magnetically arrested accretion disks, where near-horizon magnetic fields are dynamically important. We use the models to infer a mass accretion rate onto the black hole in M87 of (3–20) × 10−4 M⊙ yr−1.

 

Flyaway

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Polarimetric Properties of Event Horizon Telescope Targets from ALMA

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We present the results from a full polarization study carried out with the Atacama Large Millimeter/submillimeter Array (ALMA) during the first Very Long Baseline Interferometry (VLBI) campaign, which was conducted in 2017 April in the λ3 mm and λ1.3 mm bands, in concert with the Global mm-VLBI Array (GMVA) and the Event Horizon Telescope (EHT), respectively. We determine the polarization and Faraday properties of all VLBI targets, including Sgr A*, M87, and a dozen radio-loud active galactic nuclei (AGNs), in the two bands at several epochs in a time window of 10 days. We detect high linear polarization fractions (2%–15%) and large rotation measures (RM > 103.3–105.5 rad m−2), confirming the trends of previous AGN studies at millimeter wavelengths. We find that blazars are more strongly polarized than other AGNs in the sample, while exhibiting (on average) order-of-magnitude lower RM values, consistent with the AGN viewing angle unification scheme. For Sgr A* we report a mean RM of (−4.2 ± 0.3) × 105 rad m−2 at 1.3 mm, consistent with measurements over the past decade and, for the first time, an RM of (–2.1 ± 0.1) × 105 rad m−2 at 3 mm, suggesting that about half of the Faraday rotation at 1.3 mm may occur between the 3 mm photosphere and the 1.3 mm source. We also report the first unambiguous measurement of RM toward the M87 nucleus at millimeter wavelengths, which undergoes significant changes in magnitude and sign reversals on a one year timescale, spanning the range from −1.2 to 0.3 × 105 rad m−2 at 3 mm and −4.1 to 1.5 × 105 rad m−2 at 1.3 mm. Given this time variability, we argue that, unlike the case of Sgr A*, the RM in M87 does not provide an accurate estimate of the mass accretion rate onto the black hole. We put forward a two-component model, comprised of a variable compact region and a static extended region, that can simultaneously explain the polarimetric properties observed by both the EHT (on horizon scales) and ALMA (which observes the combined emission from both components). These measurements provide critical constraints for the calibration, analysis, and interpretation of simultaneously obtained VLBI data with the EHT and GMVA.

 

Grey Havoc

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chimeric oncogene

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beauty quark
That's just another name for the bottom quark.

So why the two different names then? It just adds to the confusion, as if particle physics is not confusing enough.
Presumably the author didn't like "Top" and "Bottom" and preferred "Truth" and "Beauty". There was a naming scuffle in the 90s.
The former (Top and Bottom), methinks, won the official nomenclature game back in the 90s against the latter. Old professors don't like changing their habits, and like their own idiosyncrasies.
Say Top and Bottom and everyone knows what you're talking about.
 

Flyaway

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To help answer this question would be if we could get samples back from the Moon’s South Pole.

Remains of impact that created the Moon may lie deep within Earth

Desch says the team could test its idea by looking for geochemical similarities between the island lavas and rocks from the Moon’s mantle. None of the Apollo samples capture the unaltered mantle, which is one reason scientists want samples from the Moon’s largest impact crater, on its south pole, where such rocks may be exhumed. NASA and China are both planning robotic missions to the south pole this decade, and it is a leading candidate site for NASA’s return of astronauts to the Moon.

 

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Possible discovery of the first intermediate mass black hole.

Summary:
Scientists discover one of the first black holes of its kind. Intermediate mass black holes (100 to 100,000 times the mass of the sun) have only been directly detected once before (LIGO, last year). They form an important link between the smaller black holes left behind after the deaths of stars, and the supermassive black holes which lurk in the hearts of every galaxy. The astrophysicists also find that there are about 40,000 of these objects in the neighbourhood of our galaxy.

 

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Dark energy may not exist and it’s all dark matter.

Consistency analysis of a Dark Matter velocity dependent force as an alternative to the Cosmological Constant

A range of cosmological observations demonstrate an accelerated expansion of the Universe, and the most likely explanation of this phenomenon is a cosmological constant. Given the importance of understanding the underlying physics, it is relevant to investigate alternative models. This article uses numerical simulations to test the consistency of one such alternative model. Specifically, this model has no cosmological constant, instead the dark matter particles have an extra force proportional to velocity squared, somewhat reminiscent of the magnetic force in electrodynamics. The constant strength of the force is the only free parameter. Since bottom-up structure formation creates cosmological structures whose internal velocity dispersions increase in time, this model may mimic the temporal evolution of the effect from a cosmological constant. It is shown that models with force linearly proportional to internal velocites, or models proportional to velocity to power three or more cannot mimic the accelerated expansion induced by a cosmological constant. However, models proportional to velocity squared are still consistent with the temporal evolution of a Universe with a cosmological model.


 

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Fluid-like elastic response of superionic NH3 in Uranus and Neptune

Significance

H2O and NH3 are representative materials comprising the mantle of ice giant planets. While H2O probably exists as the superionic state, in which hydrogen rapidly diffuses through oxygen sublattices, in the deep mantle of Uranus and Neptune, the stability field and physical properties of the superionic phase of NH3 are poorly understood. Our Brillouin study for NH3 suggested a new superionic phase exhibiting a longitudinal wave velocity comparable to that of the liquid, which is stable in the mantle of Uranus and Neptune at pressures higher than ∼50 GPa. We suggest that the superionic NH3 is nonviscous and thus cannot contribute to the internal stratification responsible for generation of the nondipolar magnetic fields observed at the icy planets.


 

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Related paper:

Supernova triggers for end-Devonian extinctions

 
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Flyaway

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As the JWST thread is still locked I will post this here.

 

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A new study shows a correlation between the end of solar cycles and a switch from El Nino to La Nina conditions in the Pacific Ocean, suggesting that solar variability can drive seasonal weather variability on Earth.


If the connection outlined in the journal Earth and Space Science holds up, it could significantly improve the predictability of the largest El Nino and La Nina events, which have a number of seasonal climate effects over land. For example, the southern United States tends to be warmer and drier during a La Nina, while the northern U.S. tends to be colder and wetter.

The paper does not delve into what physical connection between the Sun and Earth could be responsible for the correlation, but the authors note that there are several possibilities that warrant further study, including the influence of the Sun's magnetic field on the amount of cosmic rays that escape into the solar system and ultimately bombard Earth. However, a robust physical link between cosmic rays variations and climate has yet to be determined.

"If further research can establish that there is a physical connection and that changes on the Sun are truly causing variability in the oceans, then we may be able to improve our ability to predict El Nino and La Nina events," McIntosh said.


Related paper:

Termination of Solar Cycles and Correlated Tropospheric Variability

Abstract

The Sun provides the energy required to sustain life on Earth and drive our planet's atmospheric circulation. However, establishing a solid physical connection between solar and tropospheric variability has posed a considerable challenge. The canon of solar variability is derived from the 400 years of observations that demonstrates the waxing and waning number of sunspots over an 11(‐ish) year period. Recent research has demonstrated the significance of the underlying 22 years magnetic polarity cycle in establishing the shorter sunspot cycle. Integral to the manifestation of the latter is the spatiotemporal overlapping and migration of oppositely polarized magnetic bands. We demonstrate the impact of “terminators”—the end of Hale magnetic cycles—on the Sun's radiative output and particulate shielding of our atmosphere through the rapid global reconfiguration of solar magnetism. Using direct observation and proxies of solar activity going back some six decades we can, with high statistical significance, demonstrate a correlation between the occurrence of terminators and the largest swings of Earth's oceanic indices: the transition from El Niño to La Niña states of the central Pacific. This empirical relationship is a potential source of increased predictive skill for the understanding of El Niño climate variations, a high‐stakes societal imperative given that El Niño impacts lives, property, and economic activity around the globe. A forecast of the Sun's global behavior places the next solar cycle termination in mid‐2020; should a major oceanic swing follow, then the challenge becomes: when does correlation become causation and how does the process work?

 

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After the recent LHC results it’s another example of a challenge to the standard model by the behaviour of Muons.

In a landmark experiment, scientists have found fresh evidence that a subatomic particle is disobeying one of science’s most watertight theories, the Standard Model of particle physics. The gap between the model’s predictions and the particle’s newly measured behavior hints that the universe may contain unseen particles and forces beyond our current grasp.

In a seminar on Wednesday, researchers with Fermilab in Batavia, Illinois, announced the first results of the Muon g-2 experiment, which since 2018 has measured a particle called the muon, a heavier sibling of the electron that was discovered in the 1930s.

 

Flyaway

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Worth a look blog post on yesterday’s Muon announcement, and yes I only understood about a third if that of mathematics referenced in it.:oops:

 

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Five carbon- and nitrogen-bearing species in a hot giant planet’s atmosphere

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The atmospheres of gaseous giant exoplanets orbiting close to their parent stars (hot Jupiters) have been probed for nearly two decades1,2. They allow us to investigate the chemical and physical properties of planetary atmospheres under extreme irradiation conditions3. Previous observations of hot Jupiters as they transit in front of their host stars have revealed the frequent presence of water vapour4 and carbon monoxide5 in their atmospheres; this has been studied in terms of scaled solar composition6 under the usual assumption of chemical equilibrium. Both molecules as well as hydrogen cyanide were found in the atmosphere of HD 209458b5,7,8, a well studied hot Jupiter (with equilibrium temperature around 1,500 kelvin), whereas ammonia was tentatively detected there9 and subsequently refuted10. Here we report observations of HD 209458b that indicate the presence of water (H2O), carbon monoxide (CO), hydrogen cyanide (HCN), methane (CH4), ammonia (NH3) and acetylene (C2H2), with statistical significance of 5.3 to 9.9 standard deviations per molecule. Atmospheric models in radiative and chemical equilibrium that account for the detected species indicate a carbon-rich chemistry with a carbon-to-oxygen ratio close to or greater than 1, higher than the solar value (0.55). According to existing models relating the atmospheric chemistry to planet formation and migration scenarios3,11,12, this would suggest that HD 209458b formed far from its present location and subsequently migrated inwards11,13. Other hot Jupiters may also show a richer chemistry than has been previously found, which would bring into question the frequently made assumption that they have solar-like and oxygen-rich compositions.

 

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Summary
Over time, sea levels have risen and fallen with temperatures—but Earth's total surface water was always assumed to be constant. Now, evidence is mounting that some 3 billion to 4 billion years ago, the planet's oceans held nearly twice as much water—enough to submerge today's continents. Rocks in today's mantle, the thick layer beneath the crust, are thought to sequester an ocean's worth of water or more in their mineral structures. But early in Earth's history, the mantle, warmed by radioactivity, was four times hotter. Work using hydraulic presses has shown that many minerals would be unable to hold as much hydrogen and oxygen at mantle temperatures and pressures. A new model of the mantle's evolution through time, based on these results, suggests the mantle could have held far less water in the past. And the most likely home for that water was the surface. This flood could have primed the engine of plate tectonics and made it more difficult for life to start on land.

Damn... this smells a bit like Stephan Baxter "Flood" trilogy. Except the water is elsewhere, and deeper.
 

Flyaway

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Summary
Over time, sea levels have risen and fallen with temperatures—but Earth's total surface water was always assumed to be constant. Now, evidence is mounting that some 3 billion to 4 billion years ago, the planet's oceans held nearly twice as much water—enough to submerge today's continents. Rocks in today's mantle, the thick layer beneath the crust, are thought to sequester an ocean's worth of water or more in their mineral structures. But early in Earth's history, the mantle, warmed by radioactivity, was four times hotter. Work using hydraulic presses has shown that many minerals would be unable to hold as much hydrogen and oxygen at mantle temperatures and pressures. A new model of the mantle's evolution through time, based on these results, suggests the mantle could have held far less water in the past. And the most likely home for that water was the surface. This flood could have primed the engine of plate tectonics and made it more difficult for life to start on land.

Damn... this smells a bit like Stephan Baxter "Flood" trilogy. Except the water is elsewhere, and deeper.
Earth has been many things in its past seemingly, including being a giant snowball more than once.

View: https://youtu.be/4ONwQV26L-k
 

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Long since time to bring back the real 'Planet Nine', methinks.

There is no definition (based in astronomy rather than tradition) in which the solar system has exactly 9 planets. It's either 8 or hundreds.
Pluto was arguably demoted from planetary status solely because of a combination of rather dodgy science and even more toxic politics. Its later redesignation as a minor planet was an belated (and unsuccessful) attempt to mollify the critics of that move which only helped to illustrate just how wrong headed the IAU's original decision was.
Can you please respond to the specific criticism raised by Hobbes. If Pluto is a planet, why is Eris not one? The demotion of Pluto from planethood was not based on "dodgy science", it was based on the rather reasonable desire to define planets as something we don't have literal hundreds of. There are definitions of "planet" where Pluto qualifies. However, in those definitions it's never planet 9. It's planet 10 (if counting discovery order or mass), planet 11 (if counting distance from sun), etc etc.
 

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I'm afraid that I have to thoroughly disagree with you there. For one thing, you are thinking that discredited claim that Eris was larger than Pluto might have some credibility after all, I take it?
 

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I'm afraid that I have to thoroughly disagree with you there. For one thing, you are thinking that discredited claim that Eris was larger than Pluto might have some credibility after all, I take it?
Eris is heavier than Pluto, but has slightly lower diameter. We have a very accurate measure for it's mass from the orbit of Dysnomia, and a really accurate measure for Pluto's mass from the orbit of Charon.

It's unreasonable to expect that Pluto or Eris is the largest of the TNOs. Most of them are yet to be discovered, and the distribution we have so far doesn't make them seem that exceptional.

Do you feel that Eris should or should not be considered a planet? How about Ceres?
 

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