среда, 10 октября 2018 г.

‘Eagle of the Ninth’ Carved Roman Stone, Yorkshire Museum, York,…


‘Eagle of the Ninth’ Carved Roman Stone, Yorkshire Museum, York, 7.10.18.


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Remarkable flares from the galactic centre

Sagittarius A* (Sgr A*), the supermassive black hole at the center of our Milky Way Galaxy, is 100 times closer to us than any other SMBH and therefore a prime candidate for studies of how matter radiates as it accretes onto black holes. SgrA* has been observed for decades and rapid fluctuations reported from X-ray to the near infrared wavelengths (intervening dust reduces optical light signals by a factor of over a trillion) and at submillimeter and radio wavelengths.











Remarkable flares from the galactic center
A multiwavelength view of the field around the Milky Way’s galactic center seen from the X-ray (blue) through the infrared
(red). Astronomers have measured flaring events at multiple wavelengths coming from the supermassive black hole
at the very center [Credit: X-ray: NASA/CXC/UMass/D. Wang et al.; Optical: NASA/ESA/STScI/D.Wang et al.;
IR: NASA/JPL-Caltech/SSC/S.Stolovy]

Modeling the mechanisms of light variability is a direct challenge to our understanding of accretion onto SMBHs, but it is thought that correlations between flare timing at different wavelengths could reveal information about the spatial structure, for example if hotter material is located in a smaller zone closer to the black hole. One of the chief barriers to progress is the paucity of simultaneous multi-wavelength observations.


CfA astronomers Giovanni Fazio, Joe Hora, Steve Willner, Matt Ashby, Mark Gurwell and Howard Smith and a team of colleagues carried out a series of multiwavelength monitoring campaigns that included the IRAC camera onboard the Spitzer Space Telescope and the Chandra X-ray Observatory as well as the ground-based Keck telescope and the Submillimeter Array.


Spitzer was able to monitor the black hole fluctuations continuously for 23.4 hours during each session, something that no ground-based observatory is capable of doing, and something that reliably enables scientists to spot slow trends (as distinct from short bursts).


Computational modeling of the emission from the vicinity of a black hole is a complex undertaking that among other things requires simulating how the material accretes, how it is heated and radiates, and (since all this happens close to a possibly rotating black hole) how general relativity predicts the radiation will appear to distant observers.


Theorists suspect that shorter wavelength emission arises closer in and cooler emission farther out, with the former produced first and the latter subsequently. A time delay therefore might reflect the distance between these zones, and indeed previous sets of observations, some by this same team, did find evidence that hot, near-infrared flaring preceded the submillimeter flares seen by the SMA.


In their new paper, the scientists report on two flares that apparently violate these and other previous patterns: the first event occurred simultaneously at all wavelengths; in the second event the X-ray, near-infrared and submillimeter flares all turned on within one hour of each other, not quite simultaneous but still unexpectedly close. The new observations will be extended with future simultaneous campaigns, and will help theorists refine their still quite speculative set of choices.


The findings are published in The Astrophysical Journal.


Source: Harvard-Smithsonian Center for Astrophysics [October 08, 2018]




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Hot X-ray glow from massive cluster of galaxies

Astronomers using ESA’s XMM-Newton space observatory have captured the X-ray glow (shown here in purple) emitted by the hot gas that pervades the galaxy cluster XLSSC006.











Hot X-ray glow from massive cluster of galaxies
Credit: ESA/XMM-Newton (X-rays); CFHT-LS (optical); XXL Survey

The cluster is home to a few hundreds of galaxies, large amounts of diffuse, X-ray bright gas, and even larger amounts of dark matter, with a total mass equivalent to some 500 trillion solar masses. Because of its distance from us, we are seeing this galaxy cluster as it was when the Universe was only about nine billion years old.


The galaxies that belong to the cluster are concentrated towards the centre, with two dominant members. Since galaxy clusters normally have only one major galaxy at their core, this suggests that XLSSC006 is undergoing a merger event.


Pictured in this view, where the X-ray data are combined with a three-colour composite of optical and near-infrared data from the Canada-France-Hawaii Telescope, are a multitude of other galaxies. Some are closer to us than the cluster – like the spiral galaxy towards the top right – and some are farther away. The image also shows a handful of foreground stars belonging to our Milky Way galaxy, which stand out with their diffraction spikes (a common artefact of astronomical images), while the small purple dots sprinkled across the frame are point sources of X-rays, many of them beyond the Milky Way.


The X-ray data were obtained as part of the XXL Survey, XMM-Newton’s largest observational programme to date, with follow-up observations performed by a number of other observatories around the world and in space. The latest XXL Survey release contains data for 365 galaxy clusters, tracing their large-scale distribution across cosmic history. These observations are helping astronomers refine our understanding of the Universe’s structure and evolution, and will serve as a reference for ESA’s future missions Euclid and Athena.


Source: European Space Agency [October 08, 2018]




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Novel technique quickly maps young ice deposits and formations on Mars

A new investigative technique has shown the latitudinal distribution of ice-rich landforms on Mars. This large-scale study enables future, more detailed investigations to study several young deposits of ice and sediment in the north polar basin.











Novel technique quickly maps young ice deposits and formations on Mars
Localization of the studied regions in the northern plains of Mars
[Credit: Planetary Science Institute]

“The young ice deposits are extremely important for several reasons. First, they represent a different epoch in Mars’ climate history when ice was stable at the mid-latitudes. We can probe them for more information and gather details about Mars climate,” said Isaac B. Smith, Research Scientist at the Planetary Science Institute and co-author of three new papers on the topic. “Second, if humans are to explore Mars, they will want to go to mid-latitude locations where the Sun is up all year. Identifying where the ice is supports that. Finally, astrobiologists are very interested in locations where ice and rock interact because it may offer clues about habitability.”
The northern plains of Mars comprise several basins filled by sediments. The region has been proposed to have hosted an ancient ocean and currently contains ice in the ground even at latitudes where the ice is not stable. It is not known, however, what is the origin of the ice, whether it is related to the ancient ocean or recent glaciations. The ages of different surfaces and landforms are also not well known. Improving the geological context of the northern plains will help constrain outstanding questions about evolution of the climate and geology on Mars.


“We used this type of investigation to speed up the process of seeking ground ice. The team broke up very long sections into 20 kilometer by 20 kilometer squares. In their mapping, if they identified a type of feature, then the grid cell was checked,” Smith said. “This sped up the process of interpreting huge areas by orders of magnitude. The benefit is that we can now trace the latitudinal placement of various features in a spatial context, useful for making conclusions about ground ice on Mars. This is also a powerful reference map for more detailed investigations.”


Smith supported the research by providing information on what is found beneath the Martian surface using his analysis of data from NASA’s Mars SHAllow RADar sounder (SHARAD) instrument on the Mars Reconnaissance Orbiter spacecraft.


“The team mapped surface morphology but had no subsurface information before I joined, so for each project I analyzed hundreds of SHARAD observations seeking subsurface reflectors that could spatially correlate to the surface morphology they were mapping,” Smith said. “This increased confidence in their detections and provided thickness measurements for the ice that they found.”


The papers are published in the Journal of Geophysical Research: Planets (paper 1, paper 2, paper 3).


Source: Planetary Science Institute [October 08, 2018]



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Polar wandering on dwarf planet Ceres revealed

Dwarf planet Ceres experienced an indirect polar reorientation of approximately 36 degrees, a new paper by Planetary Science Institute Senior Scientist Pasquale Tricarico says.











Polar wandering on dwarf planet Ceres revealed
Ceres [Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA]

Using data from NASA’s Dawn mission, Tricarico determined the magnitude of the reorientation with three independent and corroborating lines of evidence. Global Gravity Inversion, from a paper Tricarico published in 2013, helped determine the density variations of Ceres, especially in the crust. This is what was used to find the equatorial density anomaly. Statistical analysis of topography was used for ridge analysis and the paleo-pole. And for matching the crustal fractures, a well-proven method by Matsuyama and Nimmo was used.
“The most surprising aspect of this paper is to me the observation that the pole of Ceres must have followed an indirect path to its current pole. A multi-step reorientation could mean that the equatorial density anomaly was still evolving during the reorientation, and this could be because the crust and mantle were weakly rotationally coupled, allowing the crust to start reorienting while the mantle would lag behind,” Tricarico said. “If crust and mantle are allowed to shift with respect to one another, that could point to a layer of reduced friction between crust and mantle, and one of the possible mechanisms to reduce friction could be an ancient water ocean beneath the crust.”
The Dawn mission has orbited Ceres for more than three years, gathering very detailed observations and allowing the construction of detailed geophysical models. These detailed models can then be adapted for comparison to other icy bodies, Tricarico said. One such example is the parallel between the well-known equatorial ridge of Iapetus, the moon of Saturn, and the remnants of the paleo-equatorial ridge of Ceres.


Tricarico’s paper “True polar wander of Ceres due to heterogeneous crustal density” appears in Nature Geoscience.


Source: Planetary Science Institute [October 08, 2018]




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UN report on global warming of 1.5°C approved by governments

Limiting global warming to 1.5°C would require rapid, far-reaching and unprecedented changes in all aspects of society, the IPCC said in a new assessment. With clear benefits to people and natural ecosystems, limiting global warming to 1.5°C compared to 2°C could go hand in hand with ensuring a more sustainable and equitable society, the Intergovernmental Panel on Climate Change (IPCC) said on Monday.











UN report on global warming of 1.5°C approved by governments
Credit: Tom Wang/Shutterstock

The Special Report on Global Warming of 1.5°C was approved by the IPCC on Saturday in Incheon, Republic of Korea. It will be a key scientific input into the Katowice Climate Change Conference in Poland in December, when governments review the Paris Agreement to tackle climate change.


“With more than 6,000 scientific references cited and the dedicated contribution of thousands of expert and government reviewers worldwide, this important report testifies to the breadth and policy relevance of the IPCC,” said Hoesung Lee, Chair of the IPCC.


Ninety-one authors and review editors from 40 countries prepared the IPCC report in response to an invitation from the United Nations Framework Convention on Climate Change (UNFCCC) when it adopted the Paris Agreement in 2015.


The report’s full name is Global Warming of 1.5°C, an IPCC special report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty.


“One of the key messages that comes out very strongly from this report is that we are already seeing the consequences of 1°C of global warming through more extreme weather, rising sea levels and diminishing Arctic sea ice, among other changes,” said Panmao Zhai, Co-Chair of IPCC Working Group I.


The report highlights a number of climate change impacts that could be avoided by limiting global warming to 1.5°C compared to 2°C, or more. For instance, by 2100, global sea level rise would be 10 cm lower with global warming of 1.5°C compared with 2°C. The likelihood of an Arctic Ocean free of sea ice in summer would be once per century with global warming of 1.5°C, compared with at least once per decade with 2°C. Coral reefs would decline by 70-90 percent with global warming of 1.5°C, whereas virtually all (> 99 percent) would be lost with 2°C.


“Every extra bit of warming matters, especially since warming of 1.5°C or higher increases the risk associated with long-lasting or irreversible changes, such as the loss of some ecosystems,” said Hans-Otto Pörtner, Co-Chair of IPCC Working Group II.


Limiting global warming would also give people and ecosystems more room to adapt and remain below relevant risk thresholds, added Pörtner. The report also examines pathways available to limit warming to 1.5°C, what it would take to achieve them and what the consequences could be. “The good news is that some of the kinds of actions that would be needed to limit global warming to 1.5°C are already underway around the world, but they would need to accelerate,” said Valerie Masson-Delmotte, Co-Chair of Working Group I.


The report finds that limiting global warming to 1.5°C would require “rapid and far-reaching” transitions in land, energy, industry, buildings, transport, and cities. Global net human-caused emissions of carbon dioxide (CO2) would need to fall by about 45 percent from 2010 levels by 2030, reaching ‘net zero’ around 2050. This means that any remaining emissions would need to be balanced by removing CO2 from the air.


“Limiting warming to 1.5°C is possible within the laws of chemistry and physics but doing so would require unprecedented changes,” said Jim Skea, Co-Chair of IPCC Working Group III.


Allowing the global temperature to temporarily exceed or ‘overshoot’ 1.5°C would mean a greater reliance on techniques that remove CO2 from the air to return global temperature to below 1.5°C by 2100. The effectiveness of such techniques are unproven at large scale and some may carry significant risks for sustainable development, the report notes.


“Limiting global warming to 1.5°C compared with 2°C would reduce challenging impacts on ecosystems, human health and well-being, making it easier to achieve the United Nations Sustainable Development Goals,” said Priyardarshi Shukla, Co-Chair of IPCC Working Group III.


The decisions we make today are critical in ensuring a safe and sustainable world for everyone, both now and in the future, said Debra Roberts, Co-Chair of IPCC Working Group II.


“This report gives policymakers and practitioners the information they need to make decisions that tackle climate change while considering local context and people’s needs. The next few years are probably the most important in our history,” she said.


The IPCC is the leading world body for assessing the science related to climate change, its impacts and potential future risks, and possible response options.


The report was prepared under the scientific leadership of all three IPCC working groups. Working Group I assesses the physical science basis of climate change; Working Group II addresses impacts, adaptation and vulnerability; and Working Group III deals with the mitigation of climate change.


The Paris Agreement adopted by 195 nations at the 21st Conference of the Parties to the UNFCCC in December 2015 included the aim of strengthening the global response to the threat of climate change by “holding the increase in the global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C above pre-industrial levels.”


As part of the decision to adopt the Paris Agreement, the IPCC was invited to produce, in 2018, a Special Report on global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways. The IPCC accepted the invitation, adding that the Special Report would look at these issues in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty.


Global Warming of 1.5°C is the first in a series of Special Reports to be produced in the IPCC’s Sixth Assessment Cycle. Next year the IPCC will release the Special Report on the Ocean and Cryosphere in a Changing Climate, and Climate Change and Land, which looks at how climate change affects land use.


The Summary for Policymakers (SPM) presents the key findings of the Special Report, based on the assessment of the available scientific, technical and socio-economic literature relevant to global warming of 1.5°C.


The Summary for Policymakers of the Special Report on Global Warming of 1.5°C (SR15) is available at https://www.ipcc.ch/report/sr15 or www.ipcc.ch.


Source: Intergovernmental Panel on Climate Change [October 08, 2018]



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Statistical method recreates the history of a long-abandoned village in Spain

Archaeologists now have new tools for studying the development of medieval villages and the transformation of the historical landscapes surrounding them. In a study recently published in EPJ Plus, scientists have attempted to reconstruct the history of Zornoztegi, an abandoned medieval village located in the Basque Country, Spain.











Statistical method recreates the history of a long-abandoned village in Spain
General view of early medieval occupation of Zornoztegi, Alava, Spain
[Credit: P. Ricci et al. 2018]

To do so they rely on the various analysis methods available to archaeologists, including radiocarbon dating, archaeological and historical records, archaeobotanical and optical microscope analyses of samples found on the site, together with a statistical analysis model. Paola Ricci from the University of Campania “Luigi Vanvitelli” in Italy and colleagues used this approach to establish the history of the village in the time leading up to the Middle Ages.


Archaeological evidence showed that the first occupation of the site dated back to the Chalcolithic period. After a long hiatus, it was again occupied in the Late Roman period until the Late Middle Ages.


Unfortunately, most of the superficial archaeological clues were lost over time, and with them the ability to establish connections between various remnant structures from the village. In response, the team used a statistical method to integrate information from radiocarbon dating, including the spatial distribution of the structures and individual items found on site.


The authors found that the application of the statistical method (referred to as Bayesian statistics) in the context of radiocarbon dating makes it possible to better define the intervals of dating, thanks to models that blend the information gleaned from historical, stratigraphic or typological investigations with those derived from radiocarbon dating.


Their conclusion: thanks to this method, archaeologists no longer have to delegate the deciphering of archaeological mysteries to the laboratory, but can instead employ an integrated approach that combines archaeological data and surveys of local remains.


Source: Springer [October 09, 2018]



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Meteor Activity Outlook for September 1-7, 2018

Composite of 7 photos during the Perseids 2018. Ammersee, Germany. © Luis Calçada
Nikon Df, ƒ/2.8, 28.0 mm, ISO1000

September offers longer nights in the northern hemisphere that tend to be less hazy than those experienced in mid-summer. In the sky, no major showers are visible from either hemisphere but the northern hemisphere enjoys the advantage of higher sporadic rates. Most of the shower activity this month is produced from the Perseus-Aurigid complex active this time of year. These showers rarely produce more than 5 meteors per hour but still manage to produce most of the shower activity seen this month. Unfortunately the Perseus-Aurigid complex lies too low in the northern sky for southern hemisphere observers to view very well. Video studies have shown that the Taurids are visible as early as September 23rd, therefore after this date the Anthelion radiant will no longer be listed until the Taurid showers end in December. The Anthelion meteors are still active but their radiant is superimposed upon that of the more numerous Taurids, therefore it is impossible to properly separate these meteors. Observers in the southern hemisphere suffer from some of their lowest rates of the year this month. The Taurid radiants are not too badly placed so observers south can expect to see a little of this activity from this source this month. Lastly, recent video data has shown that the Orionids are active during the last week of the month, often being the most active radiant in the sky even though their maximum is not until October 22nd.


During this period the moon will reach its last quarter phase on Monday September 3rd. At that time the moon will lie 90 degrees west of the sun in the sky and will rise near midnight local daylight saving time (LDT) as seen from mid-northern latitudes. As the week progresses the waning crescent moon will rise later with each passing night, creating more favorable viewing conditions. The estimated total hourly meteor rates for evening observers this week is near 4 as seen from mid-northern latitudes and also 3 for those viewing from subtropical southern latitudes (25S). For morning observers the estimated total hourly rates should be near 14 for those viewing from mid-northern latitudes and 9 for those viewing from subtropical southern latitudes (25S). The actual rates will also depend on factors such as personal light and motion perception, local weather conditions, alertness and experience in watching meteor activity. Morning rates are reduced during this period due to moonlight. Note that the hourly rates listed below are estimates as viewed from dark sky sites away from urban light sources. Observers viewing from urban areas will see less activity as only the brighter meteors will be visible from such locations.


The radiant (the area of the sky where meteors appear to shoot from) positions and rates listed below are exact for Saturday night/Sunday morning September 1/2. These positions do not change greatly day to day so the listed coordinates may be used during this entire period. Most star atlases (available at science stores and planetariums) will provide maps with grid lines of the celestial coordinates so that you may find out exactly where these positions are located in the sky. A planisphere or computer planetarium program is also useful in showing the sky at any time of night on any date of the year. Activity from each radiant is best seen when it is positioned highest in the sky, either due north or south along the meridian, depending on your latitude. It must be remembered that meteor activity is rarely seen at the radiant position. Rather they shoot outwards from the radiant so it is best to center your field of view so that the radiant lies near the edge and not the center. Viewing there will allow you to easily trace the path of each meteor back to the radiant (if it is a shower member) or in another direction if it is a sporadic. Meteor activity is not seen from radiants that are located far below the horizon. The positions below are listed in a west to east manner in order of right ascension (celestial longitude). The positions listed first are located further west therefore are accessible earlier in the night while those listed further down the list rise later in the night.





Radiant Positions at 22:00 LDT


Radiant Positions at 22:00

Local Daylight Saving Time






Radiant Positions at 01:00 LDT


Radiant Positions at 0100

Local Daylight Saving Time






Radiant Positions at 4:00 LDT


Radiant Positions at 04:00

Local Daylight Saving Time





These sources of meteoric activity are expected to be active this week.


The center of the large Anthelion (ANT) radiant is currently located at 23:24 (351) -04. This position lies on the Aquarius/Pisces border , 4 degrees northeast of the 4th magnitude star known as phi Aquarii. Due to the large size of this radiant, Anthelion activity may also appear from western Pisces and northwestern Cetus as well as Aquarius. This radiant is best placed near 0200 LDT, when it lies on the meridian and is located highest in the sky. Hourly rates at this time should be near 2 no matter your location. With an entry velocity of 30 km/sec., the average Anthelion meteor would be of medium-slow velocity.


The first of the September Epsilon Perseids (SPE) should be seen this week. This stream is active from September 3 through October 3 with the peak occurring on September 11th. The radiant is currently located at 02:33 (038) +37. This position lies in northeastern Triangulum, 4 degrees northeast of the 4th magnitude star known as gamma Trianguli. The radiant is best placed near 0500 LDT, when it lies highest above the horizon. Rates are expected to be less than 1 no matter your location. With an entry velocity of 65 km/sec., most activity from this radiant would be swift.


The nu Eridanids (NUE) were co-discovered by Japanese observers using SonotoCo and Juergen Rendtel and Sirko Molau of the IMO. Activity from this long-period stream stretches from August 24 all the way to November 16. Maximum activity occurs on September 8th. The radiant currently lies at 03:45 (055) +02, which places it in southwestern Taurus, 4 degrees southwest of the 4th magnitude star known as nu Tauri. This area of the sky is best seen during the last dark hour before dawn when the radiant lies highest in a dark sky. Current rates are expected to be near 1 per hour during this period no matter your location. With an entry velocity of 67 km/sec., the average meteor from this source would be of swift velocity.


The eta Eridanids (ERI) were discovered by Japanese observers back in 2001. Activity from this stream is seen from July 23 though September 17 with maximum activity occurring on August 11. The radiant currently lies at 04:12 (063) -06, which places it in northern Eridanus just west the spot occupied by the 4th magnitude star known as Beid (Omicron1 Eridani). This area of the sky is best seen during the last dark hour before dawn when the radiant lies highest in a dark sky. Current rates are expected to be less than 1 per hour during this period no matter your location. With an entry velocity of 65 km/sec., the average meteor from this source would be of swift velocity.


The Aurigids (AUR) are currently active from a radiant located at 06:08 (092) +39, which places it in eastern Auriga, 3 degrees northeast of the 3rd magnitude star known as theta Aurigae. This area of the sky is best seen during the last dark hour before dawn when the radiant lies highest in a dark sky. Current rates are expected to be near 1 per hour as seen fro the northern hemisphere and less than 1 as seen from south of the equator. With an entry velocity of 67 km/sec., the average meteor from this source would be of swift velocity.


The Daytime zeta Cancrids (ZCA) were discovered back in 1964 by C.S. Nilsson in a southern hemisphere radio survey of meteor streams. This stream is active from August 13 through September 10 with maximum activity occurring on September 3rd. The radiant is currently located at 09:00 (135) +12, which places it in southeastern Cancer, very close to the spot occupied by the 4th magnitude star known as Acubens (alpha Cancri). This area of the sky is located only 30 degrees  west of the sun so any possibility of seeing these meteors would be limited to the time just before the start of morning twilight. Current rates are expected to be less 1 per hour no matter your location. With an entry velocity of 42 km/sec., the average meteor from this source would be of medium velocity.


As seen from the mid-northern hemisphere (45N) one would expect to see approximately 10 sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near 3 per hour. As seen from the tropical southern latitudes (25S), morning rates would be near 6 per hour as seen from rural observing sites and 2 per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Morning rates are reduced during this period due to moonlight.


The list below offers the information from above in tabular form. Rates and positions are exact for Saturday night/Sunday morning except where noted in the shower descriptions.













































































SHOWER DATE OF MAXIMUM ACTIVITY CELESTIAL POSITION ENTRY VELOCITY CULMINATION HOURLY RATE CLASS
RA (RA in Deg.) DEC Km/Sec Local Daylight Saving Time North-South
Anthelions (ANT) 23:24 (351) -04 30 02:00 2 – 2 II
September Epsilon Perseids (SPE) Sep 11 02:33 (038) +37 65 06:00 <1 – <1 II
nu Eridanids (NUE) Sep 08 03:45 (055) +02 67 07:00 1 – 1 IV
eta Eridanids (ERI) Aug 11 04:12 (063) -06 65 07:00 <1 – <1 IV
Aurigids (AUR) Sep 01 06:12 (093) +39 67 09:00 1 – <1 II
Daytime zeta Cancrids (ZCA) Sep 03 09:00 (135) +12 42 12:00 <1 – <1 IV

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2018 October 10 Sun Dance Video Credit: NASA, SDO; Processing:…


2018 October 10


Sun Dance
Video Credit: NASA, SDO; Processing: Alan Watson via Helioviewer


Explanation: Sometimes, the surface of our Sun seems to dance. In the middle of 2012, for example, NASA’s Sun-orbiting Solar Dynamic Observatory spacecraft imaged an impressive prominence that seemed to perform a running dive roll like an acrobatic dancer. The dramatic explosion was captured in ultraviolet light in the featured time-lapse video covering about three hours. A looping magnetic field directed the flow of hot plasma on the Sun. The scale of the dancing prominence is huge – the entire Earth would easily fit under the flowing arch of hot gas. A quiescent prominence typically lasts about a month, and may erupt in a Coronal Mass Ejection (CME) expelling hot gas into the Solar System. The energy mechanism that creates a solar prominence is still a topic of research. Unlike 2012, this year the Sun’s surface is significantly more serene, featuring fewer spinning prominences, as it is near the minimum in its 11-year magnetic cycle.


∞ Source: apod.nasa.gov/apod/ap181010.html


HiPOD (20 September 2018): Dark Dunes in Ius Chasma   – This…




HiPOD (20 September 2018): Dark Dunes in Ius Chasma


   – This image is part of a campaign to monitor the dunes over three Earth years, about 1.6 Mars years. (266 km above the surface. Black and white is less than 5 km across; enhanced color is less than 1 km.)


NASA/JPL/University of Arizona


HiPOD (9 October 2018): Terrain at the Intersection of a Valley…



HiPOD (9 October 2018): Terrain at the Intersection of a Valley and Crater Floor 


   – 282 km above the surface. Black and white is less than 5 km across; enhanced color is less than 1 km.


NASA/JPL/University of Arizona


Meteor Activity Outlook for September 8-14, 2018

This brilliant Perseid fireball, appearing just above the Pleiades cluster, was captured by Danny Crocker-Jensen from Jefferson City, Missouri USA

During this period the moon will reach its new phase on Sunday September 9th. At that time the moon will lie near the sun in the sky and will be invisible at night. As the week progresses the waxing crescent moon will enter the evening sky but will not interfere with viewing meteor activity. The estimated total hourly meteor rates for evening observers this week is near 4 as seen from mid-northern latitudes and also 3 for those viewing from subtropical southern latitudes (25S). For morning observers the estimated total hourly rates should be near 16 for those viewing from mid-northern latitudes and 10 for those viewing from subtropical southern latitudes (25S). The actual rates will also depend on factors such as personal light and motion perception, local weather conditions, alertness and experience in watching meteor activity. Note that the hourly rates listed below are estimates as viewed from dark sky sites away from urban light sources. Observers viewing from urban areas will see less activity as only the brighter meteors will be visible from such locations.


The radiant (the area of the sky where meteors appear to shoot from) positions and rates listed below are exact for Saturday night/Sunday morning September 8/9. These positions do not change greatly day to day so the listed coordinates may be used during this entire period. Most star atlases (available at science stores and planetariums) will provide maps with grid lines of the celestial coordinates so that you may find out exactly where these positions are located in the sky. A planisphere or computer planetarium program is also useful in showing the sky at any time of night on any date of the year. Activity from each radiant is best seen when it is positioned highest in the sky, either due north or south along the meridian, depending on your latitude. It must be remembered that meteor activity is rarely seen at the radiant position. Rather they shoot outwards from the radiant so it is best to center your field of view so that the radiant lies near the edge and not the center. Viewing there will allow you to easily trace the path of each meteor back to the radiant (if it is a shower member) or in another direction if it is a sporadic. Meteor activity is not seen from radiants that are located far below the horizon. The positions below are listed in a west to east manner in order of right ascension (celestial longitude). The positions listed first are located further west therefore are accessible earlier in the night while those listed further down the list rise later in the night.





Radiant Positions at 21:00 LDT


Radiant Positions at 21:00

Local Daylight Saving Time






Radiant Positions at 01:00 LDT


Radiant Positions at 0100

Local Daylight Saving Time






Radiant Positions at 5:00 LDT


Radiant Positions at 05:00

Local Daylight Saving Time





These sources of meteoric activity are expected to be active this week.


The  chi Cygnids (CCY) are a new discovery due to an outburst observed on September 15, 2015. These meteors are expected to be active from September 8-17, with maximum occurring on September 13-14. The radiant currently lies at 19:48 (297) +30 which places it in southern Cygnus, 4 degrees northeast of the famous 3rd magnitude double star known as Albireo (beta Cygnus). Rates are expected to be low except at maximum when perhaps 1 shower member per hour may be seen. This radiant is best near 22:00 (10pm LDT) when it lies highest in the sky. With an entry velocity of 15 km/sec., the average chi Cygnid meteor would be very slow.


The center of the large Anthelion (ANT) radiant is currently located at 23:56 (359) -00. This position lies in western Pisces, 7 degrees south of the 4th magnitude star known as omega Piscium. Due to the large size of this radiant, Anthelion activity may also appear from eastern Aquarius and northwestern Cetus as well as Pisces. This radiant is best placed near 0200 LDT, when it lies on the meridian and is located highest in the sky. Hourly rates at this time should be near 2 no matter your location. With an entry velocity of 30 km/sec., the average Anthelion meteor would be of medium-slow velocity.


The September Epsilon Perseids (SPE) are active from September 3 through October 3 with the peak occurring on the night of September 10/11. The radiant is currently located at 03:06 (047) +39. This position lies just 2 degrees south of the variable star known as Algol (beta Persei). The radiant is best placed near 0500 LDT, when it lies highest above the horizon. Rates are expected to be near 2 per hour as seen from the northern hemisphere and less than 1 as seen from the southern hemisphere. With an entry velocity of 65 km/sec., most activity from this radiant would be swift.


The nu Eridanids (NUE) were co-discovered by Japanese observers using SonotoCo and Juergen Rendtel and Sirko Molau of the IMO. Activity from this long-period stream stretches from August 24 all the way to November 16. Maximum activity occurs on September 24th. The radiant currently lies at 04:12  (063) +04, which places it in southern Taurus, 3 degrees southeast of the 4th magnitude star known as nu Tauri. This area of the sky is best seen during the last dark hour before dawn when the radiant lies highest in a dark sky. Current rates are expected to be near 1 per hour during this period no matter your location. With an entry velocity of 67 km/sec., the average meteor from this source would be of swift velocity.


The eta Eridanids (ERI) were discovered by Japanese observers back in 2001. Activity from this stream is seen from July 23 though September 17 with maximum activity occurring on August 11. The radiant currently lies at 04:36 (069) -04, which places it in northeastern Eridanus, 2 degrees west of the magnitude star known as nu Eridani. This area of the sky is best seen during the last dark hour before dawn when the radiant lies highest in a dark sky. Current rates are expected to be less than 1 per hour during this period no matter your location. With an entry velocity of 65 km/sec., the average meteor from this source would be of swift velocity.


The last of the Daytime zeta Cancrids (ZCA) should be visible this weekend. This stream is active from August 13 through September 10 with maximum activity occurring on September 3rd. The radiant is currently located at 09:26 (142) +11, which places it in southeastern Cancer, just south of the 4th magnitude star known as Acubens (alpha Cancri). This area of the sky is located only 30 degrees west of the sun so any possibility of seeing these meteors would be limited to the time just before the start of morning twilight. Current rates are expected to be less 1 per hour no matter your location. With an entry velocity of 42 km/sec., the average meteor from this source would be of medium velocity.


As seen from the mid-northern hemisphere (45N) one would expect to see approximately 11 sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near 3 per hour. As seen from the tropical southern latitudes (25S), morning rates would be near 7 per hour as seen from rural observing sites and 2 per hour during the evening hours. Locations between these two extremes would see activity between the listed figures.


The list below offers the information from above in tabular form. Rates and positions are exact for Saturday night/Sunday morning except where noted in the shower descriptions.













































































SHOWER DATE OF MAXIMUM ACTIVITY CELESTIAL POSITION ENTRY VELOCITY CULMINATION HOURLY RATE CLASS
RA (RA in Deg.) DEC Km/Sec Local Daylight Saving Time North-South
chi Cygnids (CCY) Sept 13-14 19:48 (297) +30 15 22:00 <1 – <1 IV
Anthelions (ANT) 23:56 (359) -00 30 02:00 2 – 2 II
September Epsilon Perseids (SPE) Sep 11 03:06 (047) +39 65 06:00 2 – <1 II
nu Eridanids (NUE) Sep 24 04:12  (063) +04 67 07:00 1 – 1 IV
eta Eridanids (ERI) Aug 11 04:36 (069) -04 65 07:00 <1 – <1 IV
Daytime zeta Cancrids (ZCA) Sep 03 09:26 (142) +11 42 12:00 <1 – <1 IV

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Why huskies have blue eyes

DNA testing of more than 6,000 dogs has revealed that a duplication on canine chromosome 18 is strongly associated with blue eyes in Siberian Huskies, according to a study published in the open-access journal PLOS Genetics by Adam Boyko and Aaron Sams of Embark Veterinary, Inc., and colleagues. Embark is a dog DNA startup company headquartered in Boston, MA, and Ithaca, NY, and research partner of the Cornell University College of Veterinary Medicine. According to the authors, this represents the first consumer genomics study ever conducted in a non-human model and the largest canine genome-wide association study to date.











Why huskies have blue eyes
Embark dog, Lakota, shows off bright blue eyes [Credit: Jamie Leszczak]

Consumer genomics enables genetic discovery on an unprecedented scale by linking very large databases of genomic data with phenotype information voluntarily submitted via web-based surveys. But the promise of consumer genomic data is not limited to human research. Genomic tools for dogs are readily available but the genetic underpinnings of many important traits remain undiscovered. Although two genetic variants are known to underlie blue eye color in some dogs, these do not explain the trait in some other dogs, like Siberian Huskies.


To address this gap in knowledge, Boyko, Sams and colleagues used a diverse panel of 6,070 genetically tested dogs with owners that contributed phenotype data via web-based surveys and photo uploads. They found that a 98.6-kilobase duplication on chromosome 18 near the ALX4 gene, which plays an important role in mammalian eye development, was strongly associated with variation in blue eye color, primarily in Siberian Huskies but also in non-merle Australian Shepherds.


One copy of the variant was enough to cause blue eyes or heterochromia (blue and brown eyes), although some dogs with the variant did not have blue eyes, so other genetic or environmental factors are still involved. Future studies of the functional mechanism underlying this association may lead to the discovery of a novel pathway by which blue eyes develop in mammals.


From a broader perspective, the results underscore the power of consumer data-driven discovery in non-human species, especially dogs, where there is intense owner interest in the personal genomic information of their pets, a high level of engagement with web-based surveys, and an underlying genetic architecture ideal for mapping studies.


Aaron J. Sams adds: “Using genetic data from the pets of our customers, combined with eye colors reported by customers for those same animals, we have discovered a genetic duplication that is strongly associated with blue eye color. This study demonstrates the power of the approach that Embark is taking towards improving canine health. In a single year, we collected enough data to conduct the largest canine study of its kind. Embark is currently pursuing similar research projects in a range of morphological and health-related traits and we hope to continue to use our platform to move canine genetics and health forward in a very real way.”


Source: PLOS [October 05, 2018]



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Breathing life into our planet and others

A new study has produced a detailed estimation for when there was enough oxygen in the Earth’s atmosphere to support large land-based life, such as dinosaurs and eventually humans.











Breathing life into our planet and others
Credit: Pixabay

The findings could help fill in the gaps in our understanding of the evolution of Earth’s ecology and could provide useful evidence when considering if other planets could support large oxygen-dependent life.


The paper, published in Nature Communications, names the dramatic change in the Earth’s climate as the Palaeozoic Oxygenation Event, which the authors estimate to have taken place roughly 450 million years ago.


Alexander Krause, study lead author and postgraduate researcher from the School of Earth and Environment, said: “Fully understanding the history of oxygen on Earth opens the door to answering many other questions about how our planet has evolved to support a wide variety of life.


“These findings are relevant for biologists, palaeontologists, geologists and chemists; and for scientists looking for life on other planets.


“We show that Earth’s atmosphere was not breathable for most of its 4.5 billion year history, which may rule out the possibility of finding intelligent life on a ‘young’ planet”.


Rebuilding the model


While previous research has explored when Earth’s atmosphere first started to contain oxygen, it has been difficult to pinpoint when oxygen levels became similar to those found today.


There is no direct record of atmospheric oxygen on Earth, but carbon and sulphur isotopes found in ancient rocks can be used to calculate a history of atmospheric oxygen.


Previously, analysis of these isotopes had suggested two major and distinct increases in atmospheric oxygen through time.


However, the most commonly used methods have oversimplified the available data, making realistic readings difficult to obtain.


The researchers, led by the University of Leeds, built a new isotope model using an improved theoretical basis, and combined this with the latest geochemical data.


The model shows a clear transition from an Earth with relatively low oxygen levels to a planet with an abundance of free atmospheric oxygen nearly 450 million years ago, paving the way for the evolution of large terrestrial animals.


Professor Simon Poulton, a co-author from the School of Earth and Environment, said: “When combined with existing geochemical data, our new model results provide a compelling case for a third, and final, major rise in atmospheric oxygen on Earth, coincident with the rise of land plants.”


Aiding the search for life


Study co-author Dr. Benjamin Mills, also from the School of Earth and Environment, said: “There are several major exoplanet survey missions scheduled over the coming decades, and an ever-expanding catalogue of planets have been found outside our solar system.


“But there is little information on which planetary characteristics are important when searching for life. We hope to use the history of oxygen on Earth to better understand when and how a planet may become habitable.


“For example, we can perhaps rule out any yet to be discovered ‘Waterworld’ planets as being habitable for humans.


“Our work shows that the oxygen rise on Earth occurred in tandem with the evolution of land plants, so photosynthesis from algae alone may not be enough to support large terrestrial animals.”


Source: University of Leeds [October 06, 2018]



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Tourmaline | #Geology #GeologyPage #Mineral Locality: Konar…


Tourmaline | #Geology #GeologyPage #Mineral


Locality: Konar Province, Nuristan, Afghanistan

Size: 11.6 x 9.4 x 6.7 cm


Photo Copyright © Anton Watzl Minerals


Geology Page

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https://www.instagram.com/p/BouaxPpFuvq/?utm_source=ig_tumblr_share&igshid=11m4uxpk6vvq6


Iron Rose | #Geology #GeologyPage #Mineral Locality: Fibbia,…


Iron Rose | #Geology #GeologyPage #Mineral


Locality: Fibbia, Tessin, Switzerland

Size: 7 x 5.5 x 3 cm


Photo Copyright © Anton Watzl Minerals


Geology Page

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Antelope Canyon | #Geology #GeologyPage #AntelopeCanyon…


Antelope Canyon | #Geology #GeologyPage #AntelopeCanyon #Arizona


Antelope Canyon is a slot canyon in the American Southwest. It is located on Navajo land east of Page, Arizona. Antelope Canyon includes two separate, photogenic slot canyon sections, referred to individually as Upper Antelope Canyon or The Crack; and Antelope Canyon or The Corkscrew.


Geology Page

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Mottramite with Dolomite | #Geology #GeologyPage…


Mottramite with Dolomite | #Geology #GeologyPage #Mineral


Locality: Tsumeb Mine, Tsumeb, Otjikoto Region, Namibia, Africa


Dimensions: 6.7 × 1.7 × 1.5 cm


Photo Copyright © Crystal Classics


Geology Page

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Elbaite Tourmaline with Lepidolite | #Geology #GeologyPage…


Elbaite Tourmaline with Lepidolite | #Geology #GeologyPage #Mineral


Locality Pederneira Mine, Sao Jose Da Safira, Minas Gerais, Brazil, South America


Dimensions 10.3 × 9.4 × 3.5 cm


Photo Copyright © Crystal Classics


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Malachite | #Geology #GeologyPage #Mineral Locality: Brixlegg -…


Malachite | #Geology #GeologyPage #Mineral


Locality: Brixlegg – Schwaz, Inntal, Tyrol, Austria, Europe


Dimensions: 3.9 × 2.7 × 2.1 cm


Photo Copyright © Crystal Classics


Geology Page

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Jupiter in the Rearview Mirror


NASA – JUNO Mission logo.


Oct. 9, 2018



In the final minutes of a recent close flyby of Jupiter, NASA’s Juno spacecraft captured a departing view of the planet’s swirling southern hemisphere.


This color-enhanced image was taken at 7:13 p.m. PDT on Sept. 6, 2018 (10:13 p.m. EDT) as the spacecraft performed its 15th close flyby of Jupiter. At the time, Juno was about 55,600 miles (89,500 kilometers) from the planet’s cloud tops, above a southern latitude of approximately 75 degrees.


Citizen scientist Gerald Eichstädt created this image using data from the spacecraft’s JunoCam imager.



Juno orbiting Jupiter

JunoCam’s raw images are available for the public to peruse and process into image products at: http://missionjuno.swri.edu/junocam.


More information about Juno is at: https://www.nasa.gov/juno and http://missionjuno.swri.edu.


Image, Animation, Text, Credits: NASA/Tony Greicius/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt.


Best regards, Orbiter.chArchive link


APOD: 2018 October 7 – The Scale of the Universe Interactive

APOD: 2018 October 7 – The Scale of the Universe Interactive


‘Enchanted garden’ discovered in Pompeii

A house with a room containing a ‘lararium’, a shrine dedicated to the Lares, protectors of the ancient Roman home, has been discovered in Pompeii and exclusively visited by ANSA.


'Enchanted garden' discovered in Pompeii

'Enchanted garden' discovered in Pompeii

'Enchanted garden' discovered in Pompeii


'Enchanted garden' discovered in Pompeii

'Enchanted garden' discovered in Pompeii










'Enchanted garden' discovered in Pompeii

Credit: La Repubblica



The room, which is incredibly well-preserved and has the largest lararium found to date in Pompeii, is an “enchanted garden”, experts said.


'Enchanted garden' discovered in Pompeii

'Enchanted garden' discovered in Pompeii

'Enchanted garden' discovered in Pompeii


'Enchanted garden' discovered in Pompeii










'Enchanted garden' discovered in Pompeii

Credit: La Repubblica



Its walls are painted with snakes, a peacock, golden beasts fighting against a black wild boar, skies decorated with birds, a well, a colored tub and the portrait of a figure that is partly man and partly a dog.


'Enchanted garden' discovered in Pompeii

'Enchanted garden' discovered in Pompeii


'Enchanted garden' discovered in Pompeii










'Enchanted garden' discovered in Pompeii
Credit: La Repubblica

The director of the Pompeii archaeological park, Massimo Osanna, told ANSA that it is “a marvelous, enigmatic room”, a treasure “to be studied in-depth”.
 
Source: ANSA [October 06, 2018]



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