среда, 4 декабря 2019 г.

2019 December 4 Electric Night Image Credit & Copyright:...

2019 December 4

Electric Night
Image Credit & Copyright: Ivan Pedretti

Explanation: It may appear, at first, like the Galaxy is producing the lightning, but really it’s the Earth. The featured nighttime landscape was taken from a southern tip of the Italian Island of Sardinia in early June. The foreground rocks and shrubs are near the famous Capo Spartivento Lighthouse, and the camera is pointed south toward Algeria in Africa. In the distance, across the Mediterranean Sea, a thunderstorm is threatening, with several electric lightning strokes caught together during this 25-second wide-angle exposure. Much farther in the distance, strewn about the sky, are hundreds of stars in the neighborhood of our Sun in the Milky Way Galaxy. Furthest away, and slanting down from the upper left, are billions of stars that together compose the central band of our Milky Way.

∞ Source: apod.nasa.gov/apod/ap191204.html

* This article was originally published here

Massive Neolithic ritual site in Poland built before 4800 BC

The neolithic structure named ‘Roundel’ in Polish because of its shape resembling a saucepan, was discovered in 2017 in New Objezierz (West Pomeranian Voivodeship). But now researchers have discovered that it was built before 4800 BC and functioned for about 200-250 years, a lot longer than archaeologists thought.

Massive Neolithic ritual site in Poland built before 4800 BC
Looking like crop circles the remains of the roundel was first spotted
by a paraglider in 2015 [Credit: Anna Cebula/PAP]
"This is quite sensational, given the fact that it coincides with the dating of structures located on the Danube, considered the oldest. It seems equally important that the four ditches surrounding the central area of the structure probably did not function simultaneously, but every few dozen years, a new ditch with an ever larger diameter was dug," said the project leader, Professor Lech Czerniak from the University of Gdansk.

He added that dating more than a dozen further samples should allow to specify how often the ditches were renewed. Thanks to this, it will be possible to determine the "ritual calendar", according to which the object was used. "It is worth realizing that many so-called pre-literate communities celebrated the most important holidays once in a few, or even a dozen or so years, but very intensely,” he said.

Massive Neolithic ritual site in Poland built before 4800 BC
The circular structure has a diameter of 110 meters and consists of four ditches
and three palisades [Credit: Marcin Bielecki/PAP]
Measuring 110 m in diameter, the structure consisted of four circular ditches with a central part protected by three palisades. Three gates led into the interior.

Since September last year, interdisciplinary research has been carried out using the latest methods to determine the function of the structure and provide information on the lives of communities living in its vicinity.

Massive Neolithic ritual site in Poland built before 4800 BC
Almost 1,000 pieces of ceramics, as well as flint and stone objects, shells, dye (ochre)
and a fragment of quartzite have been dug up [Credit: Marcin Bielecki/PAP]
This year, scientists conducted two types of research. They used non-invasive method to study the eastern part of the object and areas located north, south and east of it. Excavations were conducted around the so-called south and west gates.

"In the excavation within the west gate, we revealed the remains of four ditches. Their depth was from 1.3 to almost 2 m. Similarly to the other two gates, we also found remains of the triple palisade," Dr. Agnieszka Matuszewska from the University of Szczecin told PAP.

Massive Neolithic ritual site in Poland built before 4800 BC
Pottery sherds found at the site [Credit: Marcin Bielecki/PAP]
According to Matuszewska, during this year`s research archaeologists found numerous fragments of ceramics, flint and stone products, animal bones, as well as several lumps of pugging, shells, dye (ocher) and a fragment of quartzite.

"Compared to previous seasons, we have more bone (472 fragments) and ceramic remains (nearly 1000 fragments of vessels)," the researcher noted. Bone deposits will be analysed by archaeozoologists, and then some of them will serve as samples for radiocarbon dating at the Poznan Radiocarbon Laboratory.

Massive Neolithic ritual site in Poland built before 4800 BC
Fragment of a stone axe [Credit: Agnieszka Matuszewska/PAP]
According to the researchers, the radiocarbon dates obtained so far (eleven datings) are the most important findings. They set the object`s functioning time quite precisely at around 200-250 years, and they put the construction of the object before 4800 BC.

According to Dr. Matuszewska, palaeoenvironmental research carried out on site and in its vicinity are a very important part of the project. They are expected to allow to determine the environmental impact of the communities using the roundel in the first half of the fifth millennium BC.

Massive Neolithic ritual site in Poland built before 4800 BC
Entrance at the "west gate" [Credit: Lech Czerniak/PAP]
"But the primary focus of the project are questions about the social aspects of the functioning operation of roundels, including what prompted the inhabitants of a given region to make a huge effort in building and maintaining the roundel, where the idea and knowledge necessary to build this object came from, and how often and for how long the object was used," said Professor Czerniak.

Researchers explain that roundels were of particular importance to local communities because of their structural and ritual connections with cosmic forces. This is indicated by azimuths that can be determined between the central point of the object and its gates.

Massive Neolithic ritual site in Poland built before 4800 BC
What the roundel may have looked like in its prime
[Credit: Anna Cebula/PAP]
It is puzzling that they functioned in a fairly limited area (today`s Hungary, Austria, Czech Republic, Slovakia, Germany and Poland) and for a relatively short time between 4850 and 4600 BC. However, similar objects in terms of function, and to some extent also form, were built in different eras and regions of Europe. The most famous such object is Stonehenge.

In the third season of research of the object in New Objezierz, researchers (archaeologists and researchers specialising in other disciplines) from Gdansk, Poznan, Szczecin and Warsaw, as well as students participated. The research is financed by the National Science Centre.

Author: Elzbieta Bielecka | Source: PAP - Science in Poland [November 12, 2019]

* This article was originally published here

New Horizons Confirms Solar Wind Slows Farther from the Sun

The SWAP instrument aboard NASA's New Horizons spacecraft has confirmed that the solar wind slows as it travels farther from the Sun. This schematic of the heliosphere shows the solar wind begins slowing at approximately 4 AU radial distance from the Sun and continues to slow as it moves toward the outer solar system and picks up interstellar material. Current extrapolations reveal the termination shock may currently be closer than found by the Voyager spacecraft. However, increasing solar activity will soon expand the heliosphere and push the termination shock farther out, possibly to the 84-94 AU range encountered by the Voyager spacecraft. (Image credit: Southwest Research Institute; background artist rendering by NASA and Adler Planetarium). Hi-res image

Research could help predict when spacecraft will cross the termination shock

Measurements taken by the Solar Wind Around Pluto (SWAP) instrument aboard NASA's New Horizons spacecraft are providing important new insights from some of the farthest reaches of space ever explored. In a paper published recently in The Astrophysical Journal, New Horizons scientists show how the solar wind — the supersonic stream of charged particles blown out by the Sun — evolves at increasing distances from the Sun.

"Previously, only the Pioneer 10 and 11 and Voyager 1 and 2 missions have explored the outer solar system and outer heliosphere, but now New Horizons is doing that with more modern scientific instruments," said Heather Elliott, a staff scientist at the Southwest Research Institute, deputy principal investigator of the SWAP instrument and lead author of the paper. "Our Sun's influence on the space environment extends well beyond the outer planets, and SWAP is showing us new aspects of how that environment changes with distance."

The solar wind fills a bubble-like region of space encompassing our solar system, called the heliosphere. From aboard New Horizons, SWAP collects detailed, daily measurements of the solar wind as well as other key components called "interstellar pickup ions" in the outer heliosphere. These interstellar pickup ions are created when neutral material from interstellar space enters the solar system and becomes ionized by light from the Sun or by charge exchange interactions with solar wind ions.

The journey New Horizons is taking through the outer heliosphere contrasts that of Voyager since this solar cycle is mild compared to the very active solar cycle explored during the Voyager passage through the outer heliosphere. In addition to measuring the solar wind, SWAP is extremely sensitive and simultaneously measures the low fluxes of interstellar pickup ions with unprecedented time resolution and extensive spatial coverage. Currently, New Horizons is the only spacecraft in the solar wind beyond Mars and consequently the only spacecraft measuring the interaction between the solar wind and interstellar material in the outer heliosphere.

As the solar wind moves farther from the Sun, it encounters an increasing amount of material from interstellar space. When interstellar material is ionized, the solar wind picks up the material and, researchers theorized, slows and heats in response. SWAP has now detected and confirmed this predicted effect.

The SWAP team compared the New Horizons solar wind speed measurements from 21 to 42 astronomical units to the speeds at 1 AU from both the Advanced Composition Explorer (ACE) and Solar TErrestrial RElations Observatory (STEREO) spacecraft. (One astronomical unit, or AU, is equal to the distance between the Sun and Earth.) By 21 AU, it appeared that SWAP could be detecting the slowing of the solar wind in response to picking up interstellar material. However, when New Horizons traveled beyond Pluto, between 33 and 42 AU, the solar wind measured 6-7% slower than at the 1 AU distance, confirming the effect.

In addition to confirming the slowing of the solar wind at great distances, the change in the solar wind temperature and density could also provide a means to estimate when New Horizons will join the Voyager spacecraft on the other side of the termination shock, the boundary marking where the solar wind slows to less than the sound speed as it approaches the interstellar medium. Voyager 1 crossed the termination shock in 2004 at 94 AU, followed by Voyager 2 in 2007 at 84 AU. Based on current lower levels of solar activity and lower solar wind pressures, the termination shock is expected to have moved closer to the Sun since the Voyager crossings.

Extrapolating current trends in the New Horizons measurements also indicates that the termination shock might now be closer than when it was intersected by Voyager. At the earliest, New Horizons will reach the termination shock in the mid-2020s. As the solar cycle activity increases, the increase in pressure will likely expand the heliosphere. This could push the termination shock to the 84-94 AU range found by the Voyager spacecraft before New Horizons has time to reach it.

"New Horizons has significantly advanced our knowledge of distant planetary objects, and it's only fitting that it is now also revealing new knowledge about our own Sun and its heliosphere," said New Horizons Principal Investigator Alan Stern, of SwRI.

New Horizons is the first mission in NASA's New Frontiers program. The Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, built and operates the New Horizons spacecraft and manages the mission for NASA's Science Mission Directorate. SwRI led the payload instrument development and leads the New Horizons science and mission teams from the Tombaugh Science Operations Center located at SwRI facilities in Boulder, Colo. For more information, go to: http://pluto.jhuapl.edu/.

The paper "Slowing of the Solar Wind in the Outer Heliosphere" by Elliott, D.J. McComas, E.J. Zirnstein, B.M. Randol, P.A. Delamere, G. Livadiotis, F. Bagenal, N.P. Barnes, S.A. Stern, L.A. Young, C.B. Olkin, J. Spencer, H.A. Weaver, K. Ennico, G.R. Gladstone, and C.W. Smith, was published November 11 in The Astrophysical Journal.

* This article was originally published here

Mesolithic Hunter Gatherer Reconstruction Model, The Museum of Liverpool, Liverpool, 1.12.19.

Mesolithic Hunter Gatherer Reconstruction Model, The Museum of Liverpool, Liverpool, 1.12.19.

* This article was originally published here

A glimpse into the life of Marco Polo

A new discovery on Marco Polo was made possible thanks to the work of a team of young, brilliant Ca’ Foscari researchers (BIFLOW project, supervised by prof. Antonio Montefusco of the Department of Humanities), who have recently uncovered a previously unknown document that gives us a glimpse into Marco Polo’s life after his return to Venice and a year before his death.

A glimpse into the life of Marco Polo
Credit: Ca’ Foscari University of Venice
This extremely important finding adds a piece of the puzzle to our current knowledge of the Venetian explorer’s biography and his connections to local religious orders.

Marcello Bolognari, who recently graduated from Ca’ Foscari and is now a scholarship recipient working for the “Biflow” project, has discovered a new document bearing the name of Marco Polo. This record, dating back to 1323, belongs to the Venice State Archive (where most of the documents produced by the institutional bodies of the Venetian Republic are kept) and it concern the acceptance of a bequest left by Giovanni dalle Boccole to the Dominican friars of the Santi Giovanni e Paolo convent in Venice.

The famous traveller «Marco Paulo de confinio Sancti Iohannis Grisostomi» was among the witnesses of this notary deed; in fact, Marco Polo was known to reside in that exact part of town, where his father Nicolo and his uncle Maffeo had acquired a house. To further confirm his identity, in the long list of clergymen included in the document, we find the names of Benevenuto and Centorio, the same Dominican friars who Marco Polo included in his will the following year.

Marcello Bolognari, the protagonist of this sensational finding, graduated from the School of Archival Science, Paleography and Diplomatics of the Venice State Archive in 2017 and, since then, he has spent quite some time in the Archive’s study hall. Upon the discovery, the Archive’s officers and the research team members were immediately alerted - the bibliographical inspection that followed confirmed that the record had in fact remained undiscovered up to that point.

The connection between Marco Polo’s written work and its reception by the local community and religious circles is the object of Prof. Antonio Montefusco’s research work. Together with his team of researchers, he is currently working on the medieval translation of The Travels of Marco Polo from a historical, social and cultural point of view (within the framework of an ERC project, the StGrant 675333 “Biflow”, funded by the European Community)

The discovery of this document has proved of great importance for this project, for at least two reasons.

First of all, this piece of parchment offers new information on the life of Marco Polo following his return to Venice, a period of time on which we know almost nothing about: it paints the picture of a man who was not only involved in the management of his family’s business, but also in the religious life of that era, especially that of the Dominican order (a crucial actor in Italy’s urban society between the 13th and 14th century, especially in the symbolic and cultural field).

Secondly, the record offers a new interesting take on the fascinating theory that, after his imprisonment in Genoa and following his return to Venice, Marco Polo dedicated himself to the revision of his work (which had been drafted in Genoa together with Rustichello da Pisa in the years around 1298), employing the help of the Dominican friars at Santi Giovanni e Paolo; this revision work is attested by the peculiar traits of the so-called “redazione latina Z” (latin redaction Z), which, according to numerous records, was written in Venice, more precisely in a Dominican environment.

“One of the most fascinating - and probably lesser known - characteristics regarding the circulation of The Travels of Marco Polo consists in the many different Latin translations of the manuscript - stated Antonio Montefusco, coordinator of the research team - One of these translations was drafted at the beginning of the 12th century by a Dominican friar called Francesco Pipino, perhaps even at the request of the Order. This version was a great success and granted the distribution of the book Europe-wide. Friars immediately took interest in Marco’s written work: The Travels of Marco Polo was a precious source of information on travel routes and spiritual beliefs in the East.

For these reasons, the Dominicans, who were both missionaries and travellers, read the book, transformed it and reused it in their works up to the Modern age. This newly discovered record proves the idea that this interest was born of out of a direct relationship between the famous explorer and the Dominican order of Santi Giovanni e Paolo, which leads us to believe that the Venetian friars might have lent a hand to Marco’s revision of the book, acting almost as contemporary editors”

A new collaboration has been launched on the topic, involving the team coordinated by prof. Eugenio Burgio and dr. Samuela Simion, who are currently working on a digital integral edition of The Travels of Marco Polo (after editing the version by Giovanni Battista Ramusio). The partnering teams have recently organized a seminar on the reception of Marco Polo’s work by the Mendicant Orders, a vast research subject which will soon become an open access publication by Edizioni Ca’ Foscari, our in-house University Press. The new document will also be inserted in the publication, together with other essays on the success and transformation of The Travels of Marco Polo in the written works of mendicant friars.

It was the very idea behind this publication that became the starting point for this incredible discovery at the State Archive in Venice, as it pushed researchers to look for official records of the connection between the author of The Travels of Marco Polo and the Dominican order.

Ca’ Foscari University of Venice and the State Archive are now signing a partnership agreement that will surely stimulate new research projects on a wide array of topics.

Source: Ca' Foscari University of Venice [November 22, 2019]

* This article was originally published here

Crew Training for Two New Cargo Missions Launching This Week

ISS - Expedition 61 Mission patch.

December 3, 2019

The Expedition 61 crew aboard the International Space Station is focusing on a pair of upcoming cargo deliveries after completing a spacewalk on Monday.

SpaceX will launch its 19th Dragon resupply ship aboard a Falcon 9 rocket on Wednesday at 12:51 p.m. EST from Kennedy Space Center in Florida. Dragon is delivering nearly three tons of cargo to the orbiting lab including new science hardware such as the Confined Combustion study, Japan’s Hyperspectral Imager Suite (HISUI) and the AzTechSat-1 cubesat developed by Mexican students.

Image above: Astronaut Luca Parmitano carries the new thermal pump system that was installed on the Alpha Magnetic Spectrometer (AMS) during the third spacewalk to upgrade the AMS. Image Credit: NASA.

Commander Luca Parmitano and Flight Engineer Andrew Morgan are training to capture Dragon with the Canadarm2 robotic arm when it arrives Saturday at 5:58 a.m. Robotics controllers will take command of the Canadarm2 and then install Dragon to the Harmony module’s Earth-facing port.

Parmitano and Morgan wrapped up a spacewalk on Monday having replaced a thermal pump system on the station’s cosmic particle detector. They joined fellow astronauts Jessica Meir and Christina Koch at the end of the day Tuesday with a call to Mission Control about their spacewalk experience.

Image above: The Russian Progress 72 cargo craft is pictured shortly before undocking from the Pirs docking compartment of the International Space Station on July 29, 2019. The Progress 74 spacecraft is scheduled to launch Dec. 6, 2019, and dock at the same compartment two days later. Image Credit: NASA.

The space station is also preparing for the arrival of Russia’s Progress 74 (74P) cargo craft set for launch on Friday at 4:34 a.m. The 74P will take a three-day trip to the station and dock Monday Dec. 9 at 5:38 a.m. Cosmonauts Alexander Skvortsov and Oleg Skripochka checked out the tele-robotically operated rendezvous unit (TORU) today in the unlikely event they would need to remotely maneuver the 74P to a docking.

Related article:

NASA Television to Air Space Station Cargo Ship Launch, Docking

Related links:

Expedition 61: https://www.nasa.gov/mission_pages/station/expeditions/expedition61/index.html

Confined Combustion: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7886

Hyperspectral Imager Suite (HISUI): https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7476

AzTechSat-1: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=8055

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Text, Credits: NASA/Mark Garcia.

Best regards, Orbiter.ch

* This article was originally published here

Mesolithic Hunter Gatherer Models, The Museum of Liverpool, Liverpool, 1.12.19.

Mesolithic Hunter Gatherer Models, The Museum of Liverpool, Liverpool, 1.12.19.

* This article was originally published here

Over 1,000-year-old royal tomb found in NW China

A well-preserved tomb dating back to the Tang Dynasty (618-907) has been found in northwest China's Gansu Province, local authorities said.

Over 1,000-year-old royal tomb found in NW China
The Tuyuhun royal tomb has been found in Tianzhu Tibetan Autonomous County, Gansu Province,
according to the Gansu Provincial Institute of Cultural Relics and Archaeology
[Credit: China News Service]

According to the Gansu Institute of Cultural Relics and Archaeology, the tomb was discovered on a mountain in Chashan Village, Tianzhu Tibetan Autonomous County. It is a tomb of a royal lineage from the early and middle Tang Dynasty, according to the institute.

Over 1,000-year-old royal tomb found in NW China
Located on the ancient Silk Road trade route, Tuyuhun was a powerful kingdom established
by historical nomadic peoples [Credit: China News Service]
Over 1,000-year-old royal tomb found in NW China
Wooden figures in the east niche of the tomb
[Credit: China News Service]

The brick-chambered tomb has a 17.5-meter-long passage, where archaeologists have found wood objects, ink painted bricks and remains of sacrificial animals.

Over 1,000-year-old royal tomb found in NW China
Silk fabric covering the coffin [Credit: China News Service]
Over 1,000-year-old royal tomb found in NW China
The discovery of this, the most well-preserved tomb found so far, will aid studies of burial customs of Tuyuhun,
the Silk Road and the relationship with the Tang Dynasty (618-907), archaeologists said
[Credit: China News Service]

Over 70 sets of painted pottery and wooden figures were discovered in the niches. Archaeologists also found more than 220 articles including painted pottery, lacquer wood, stone, bronze, gold and silver objects.

Over 1,000-year-old royal tomb found in NW China
Grave epitaph found in the tomb [Credit: China News Service]
The tomb provides rich research materials on the ancient Silk Road, and is important for studying the history of ethnic groups, transportation and culture along the ancient Silk Road in the Tang Dynasty, said Chen Guoke, deputy dean of the institute.

Source: Xinhua News Agency [November 24, 2019]

* This article was originally published here

NASA’s Exoplanet-Hunting Mission Catches a Natural Comet Outburst in Unprecedented Detail

NASA - Transiting Exoplanet Survey Satellite (TESS) logo.

Dec. 3, 2019

Using data from NASA’s Transiting Exoplanet Survey Satellite (TESS), astronomers at the University of Maryland (UMD), in College Park, Maryland, have captured a clear start-to-finish image sequence of an explosive emission of dust, ice and gases during the close approach of comet 46P/Wirtanen in late 2018. This is the most complete and detailed observation to date of the formation and dissipation of a naturally-occurring comet outburst. The team members reported their results in the November 22 issue of The Astrophysical Journal Letters.

“TESS spends nearly a month at a time imaging one portion of the sky. With no day or night breaks and no atmospheric interference, we have a very uniform, long-duration set of observations,” said Tony Farnham, a research scientist in the UMD Department of Astronomy and the lead author of the research paper. “As comets orbit the Sun, they can pass through TESS’ field of view. Wirtanen was a high priority for us because of its close approach in late 2018, so we decided to use its appearance in the TESS images as a test case to see what we could get out of it. We did so and were very surprised!”

“While TESS is a powerhouse for discovering planets orbiting nearby, bright stars, its observing strategy enables so much exciting additional science,” said TESS project scientist Padi Boyd of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Since the TESS data are rapidly made public through NASA’s Mikulski Archive for Space Telescopes (MAST), it’s exciting to see scientists identifying which data are of interest to them, and then doing all kinds of additional serendipitous science beyond exoplanets.”

Animation above: This animation shows an explosive outburst of dust, ice and gases from comet 46P/Wirtanen that occurred on September 26, 2018 and dissipated over the next 20 days. The images, from NASA’s TESS spacecraft, were taken every three hours during the first three days of the outburst. Animation Credits: Farnham et al./NASA.

Normal comet activity is driven by sunlight vaporizing the ices near the surface of the nucleus, and the outflowing gases drag dust off the nucleus to form the coma. However, many comets are known to experience occasional spontaneous outbursts that can significantly, but temporarily increase the comet's activity. It is not currently known what causes outbursts, but they are related to the conditions on the comet's surface. A number of potential trigger mechanisms have been proposed, including a thermal event, in which a heat wave penetrates into a pocket of highly volatile ices, causing the ice to rapidly vaporize and produce an explosion of activity, and a mechanical event, where a cliff collapses, exposing fresh ice to direct sunlight. Thus, studies of the outburst behavior, especially in the early brightening stages that are difficult to capture, can help us understand the physical and thermal properties of the comet.

Although Wirtanen came closest to Earth on December 16, 2018, the outburst occurred earlier in its approach, beginning on September 26, 2018. The initial brightening of the outburst occurred in two distinct phases, with an hour-long flash followed by a more gradual second stage that continued to grow brighter for another 8 hours. This second stage was likely caused by the gradual spreading of comet dust from the outburst, which causes the dust cloud to reflect more sunlight overall. After reaching peak brightness, the comet faded gradually over a period of more than two weeks. Because TESS takes detailed, composite images every 30 minutes, the team was able to view each phase in exquisite detail.

“With 20 days’ worth of very frequent images, we were able to assess changes in brightness very easily. That’s what TESS was designed for, to perform its primary job as an exoplanet surveyor,” Farnham said. “We can’t predict when comet outbursts will happen. But even if we somehow had the opportunity to schedule these observations, we couldn’t have done any better in terms of timing. The outburst happened mere days after the observations started.”

The team has generated a rough estimate of how much material may have been ejected in the outburst, about one million kilograms (2.2 million pounds), which could have left a crater on the comet of around 20 meters (about 65 feet) across. Further analysis of the estimated particle sizes in the dust tail may help improve this estimate. Observing more comets will also help to determine whether multi-stage brightening is rare or commonplace in comet outbursts.

Transiting Exoplanet Survey Satellite or Tess. Image Credit: NASA

TESS has also detected for the first time Wirtanen’s dust trail. Unlike a comet’s tail—the spray of gas and fine dust that follows behind a comet, growing as it approaches the sun—a comet’s trail is a field of larger debris that traces the comet’s orbital path as it travels around the sun. Unlike a tail, which changes direction as it is blown by the solar wind, the orientation of the trail stays more or less constant over time.

“The trail more closely follows the orbit of the comet, while the tail is offset from it, as it gets pushed around by the sun’s radiation pressure. What’s significant about the trail is that it contains the largest material,” said Michael Kelley, an associate research scientist in the UMD Department of Astronomy and a co-author of the research paper. “Tail dust is very fine, a lot like smoke. But trail dust is much larger—more like sand and pebbles. We think comets lose most of their mass through their dust trails. When the Earth runs into a comet’s dust trail, we get meteor showers.”

While the current study describes initial results, Farnham, Kelley and their colleagues look forward to further analyses of Wirtanen, as well as other comets in TESS’ field of view. “We also don’t know what causes natural outbursts and that’s ultimately what we want to find,” Farnham said. “There are at least four other comets in the same area of the sky where TESS made these observations, with a total of about 50 comets expected in the first two years’ worth of TESS data. There’s a lot that can come of these data.”

TESS is a NASA Astrophysics Explorer mission led and operated by MIT in Cambridge, Massachusetts, and managed by NASA's Goddard Space Flight Center. Additional partners include Northrop Grumman, based in Falls Church, Virginia; NASA’s Ames Research Center in California’s Silicon Valley; the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts; MIT’s Lincoln Laboratory; and the Space Telescope Science Institute in Baltimore. More than a dozen universities, research institutes and observatories worldwide are participants in the mission.

Related links:

The Astrophysical Journal Letters: https://iopscience.iop.org/article/10.3847/2041-8213/ab564d

UMD Department of Astronomy: https://www.astro.umd.edu/

NASA’s Mikulski Archive for Space Telescopes (MAST): https://archive.stsci.edu/

Exoplanets: https://exoplanets.nasa.gov/

TESS (Transiting Exoplanet Survey Satellite): http://www.nasa.gov/tess

Animation (mentioned), Image (mentioned), Text, Credits: NASA/Lynn Jenner/GSFC/Claire Andreoli/University of Maryland/Matthew Wright.

Greetings, Orbiter.ch

* This article was originally published here

The Roman Helmsdale Hoard of Serving Dishes and Wine Strainers, The National Museum of Scotland,...

The Roman Helmsdale Hoard of Serving Dishes and Wine Strainers, The National Museum of Scotland, Edinburgh, November 2019.

* This article was originally published here

Hundreds of cuneiform tablets unearthed in ancient Mesopotamian city of Marad

Thousands of years ago in Mesopotamia letters written on tablets to exchange information of every nature were sent in clay ‘envelopes’. Three large portions of these envelopes, part of a discovery which is exceptional for the number and state of conservation of the artifacts, is the outcome of an archaeological excavation campaign in Iraq carried out by the University of Pisa in collaboration with the University of Siena and the Iraqi University of Al-Qadisiyyah. In particular, the archaeologists found a hundred or so fragments with cuneiform script dating back to the beginning of the 2nd millennium BC, eight of which intact or almost, as well as a rich array of ceramics and more than ninety ‘cretulae’, or rather blocks of clay with seal or string impressions which were used to secure the containers.

Hundreds of cuneiform tablets unearthed in ancient Mesopotamian city of Marad
Credit: Universita di Pisa

The archaeological investigations, which ended in November, were carried out at Tell as-Sadoum in central southern Iraq. The 50 hectare site, east of Najaf, on a branch of the Euphrates river, was identified as being Marad, an ancient city of southern Mesopotamia, whose history can be traced over a long period of time from the protodynastic period (3rd millennium BC) to the Neo-Babylonian Empire (1st millennium BC). In particular, the excavations were centred around a large temple at the top of the main hill and two other areas, one residential and the other a manufacturing district, where most of the cretulae and tablets were found.

Hundreds of cuneiform tablets unearthed in ancient Mesopotamian city of Marad
Hundreds of cuneiform tablets unearthed in ancient Mesopotamian city of Marad
Credit: Universita di Pisa
“In general, the tablets bear witness to the wealth and the lively economic and administrative life of the ancient city in Mesopotamia and often tell of business transactions as well as administrative and judicial issues,” explains Anacleto D’Agostino, contract professor of Archaeology of the Near East at the University of Pisa, who coordinated the project.

Hundreds of cuneiform tablets unearthed in ancient Mesopotamian city of Marad
Hundreds of cuneiform tablets unearthed in ancient Mesopotamian city of Marad
Credit: Universita di Pisa
“The tablets we found, from the Isin-Larsa and Old Babylonian Periods, which are currently under examination, contain purchase agreements, letters and date formulas and also mention the names of sovereigns as well as references to a few cities.”

“The tablets could also be enclosed in ‘envelopes’, of which we found dozens of fragments,” continues D’Agostino. "The ‘envelopes’ are containers modelled out of thin layers of clay with the subject of the message printed on the surface along with names or images, used to authenticate and guarantee the contents.”

Hundreds of cuneiform tablets unearthed in ancient Mesopotamian city of Marad
Hundreds of cuneiform tablets unearthed in ancient Mesopotamian city of Marad
Credit: Universita di Pisa
The complexity of the civilization of the era can in fact also be seen by the seals, frequently embossed with semi precious stones. These were often effectively the distinguishing mark and signature of prominent people and officials. The scenes engraved on them reproduce various themes and are often executed with great care and expertise by skilful craftsmen.

Hundreds of cuneiform tablets unearthed in ancient Mesopotamian city of Marad
Hundreds of cuneiform tablets unearthed in ancient Mesopotamian city of Marad
Credit: Universita di Pisa

In the fragmentary impressions brought to light during the excavations and which date back to the 3rd millennium BC, there are, for example, miniature scenes depicting heroes fighting with wild animals and imaginary creatures, enthroned divinities, a lion attacking a gazelle or rampant caprids and an elephant.

Hundreds of cuneiform tablets unearthed in ancient Mesopotamian city of Marad
Hundreds of cuneiform tablets unearthed in ancient Mesopotamian city of Marad
Credit: Universita di Pisa
“Given the excellent results of this campaign and the importance of the findings,” concludes D’Agostino, “the prospect is to continue the project through 2020 with a new mission in the field.”

Source: Universita di Pisa [November 25, 2019]

* This article was originally published here

Ballachulish Votive Female Figure (600BCE), The National Museum of Scotland, Edinburgh, November...

Ballachulish Votive Female Figure (600BCE), The National Museum of Scotland, Edinburgh, November 2019.

* This article was originally published here

Ancient Greek necropolis discovered during roadworks in Sicily

Workers installing cables under a road in the Sicilian town of Gela have uncovered part of an ancient Greek burial site.

Ancient Greek necropolis discovered during roadworks in Sicily
Credit: Regione Sicilia
Residents of Via Di Bartolo, in Gela, Sicily, had expected disrruption from roadworks this month as workers installed fibre optic cables under the street. But instead they've ended up with an archaeological dig taking place outside their front doors, after the Open Fiber cable company uncovered part of an ancient necropolis dating back to the 7th century BC.

Finds so far along the small strip of road include a ceramic water jug which contained the bones of a newborn baby, and parts of a large animal skeleton, according to local authorities.

The finds were reportedly made by Open Fiber's in-house archaeologist, Gianluca Cala, who had been on call during the installation work in case of such discoveries, which are not that unusual in Sicily.

Ancient Greek necropolis discovered during roadworks in Sicily
Credit: Regione Sicilia
A sarcophagus containing an intact skeleton thought to be from the same period was discovered earlier this month in Gela."Two weeks after the last important discovery, in what is certainly a Greek necropolis, Gela gives us other extraordinary testimonies of the past” the Sicilian regional government stated in a press release.

The area where the discoveries were made is believed to be part of a necropolis first excavated at the beginning of the twentieth century by Paolo Orsi, according to the La Sicilia newspaper.

"Once again Gela is confirmed to be a part of Sicily that can tell us an important part of our ancient history. Two important archaeological finds, a short distance from each other, show that great attention is paid to the Gela area, which I believe to be a precious treasure chest,” said the President of the Sicilian Region Nello Musumeci.

Ancient Greek necropolis discovered during roadworks in Sicily
Credit: Regione Sicilia
Open Fiber said it would be willing to enlarge the excavation area to help historians and archaeologists uncover more ancient finds in Gela, La Sicilia wrote.

Gela is believed to be the site of one of the earliest settlements of Greeks, from Rhodes and Crete.

"The newly-uncovered graves are seen as particularly important by historians," the Sicilian regional government stated, "as they're thought to hold the remains of the first settlers along with examples of the fine ceramics they brought with them."

Source: The Local [November 28, 2019]

* This article was originally published here


https://t.co/hvL60wwELQ — XissUFOtoday Space (@xufospace) August 3, 2021 Жаждущий ежик наслаждается пресной водой после нескольких дней в о...