среда, 26 июня 2019 г.

Ancient tomb with well-preserved murals discovered in north China

Seven coloured murals were discovered on the walls of an ancient tomb in north China’s Shanxi Province, according to the provincial institute of archaeology.

Ancient tomb with well-preserved murals discovered in north China
Credit: Shanxi Provincial Institute of Archaeology

Located in a village of the Shuozhou city, the brick-chambered tomb was believed to date back to the Yuan Dynasty (1271-1368). Archaeologists are excavating the tomb and the delicate murals.
The well-preserved murals depicted different themes of the time, such as a desk for ritual activities, landscapes and women.

Ancient tomb with well-preserved murals discovered in north China
Credit: Shanxi Provincial Institute of Archaeology

The clothes and hairstyles of the four painted women shed lights on the ancient fashion of northern Shanxi in the Yuan Dynasty.
Wang Xiaoyi, director of the institute, said the identity of the tomb owner is yet to be known. More information will be disclosed upon further investigation.

Ancient tomb with well-preserved murals discovered in north China
Credit: Shanxi Provincial Institute of Archaeology

«The new discoveries can provide valuable information for future studies on local burial customs and social life in Yuan dynasty,» Wang said.

Source: Xinhua News Agency [June 22, 2019]



Malta’s neglected Fort Ricasoli to finally undergo restoration

Extensive plans for the restoration of the imperilled Fort Ricasoli were given the go-ahead by the Planning Authority on Monday, six years after they were submitted.

Malta's neglected Fort Ricasoli to finally undergo restoration

Credit: WikiCommons

The plans by the government Restoration Directorate will see the restoration, in several phases, of large parts of the Kalkara fortifications – including bastion and parapet gun emplacements, ditches, ravelins, barrack blocks and a chapel – to ensure their long-term preservation.
Fort Ricasoli, built by the Knights of St John and the largest on the island, has been in a dire state of deterioration for years, with sections of its outer bastions already having crashed into the sea and heritage experts warning that further collapse was inevitable without immediate intervention.

Malta's neglected Fort Ricasoli to finally undergo restoration
Credit: WikiCommons

A report drawn up by the Restoration Directorate as part of the planning process noted that the deterioration had largely been caused by the rough seas which continuously batter the exposed ramparts.

The report concluded that wave action had caused extensive structural damage to the bastions facing the open sea, causing their collapse, while salt contamination had further attacked masonry elements and rock outcrops.

Malta's neglected Fort Ricasoli to finally undergo restoration
Credit: WikiCommons

Extensive rust damage was found on steel structural elements and fittings added in later years, while further damage had been caused by the unchecked growth of algae and vegetation, neglect and lack of maintenance, as well as pollution from the burning of fossil fuels.
The planned restoration works include cleaning and reconstruction missing sections of the limestone fabric, restoration of deteriorated masonry and collapsed structures, and structural consolidation.

Malta's neglected Fort Ricasoli to finally undergo restoration
Credit: WikiCommons

The rock face below the fort will also be consolidated as a hazard reduction measure.

Although the application for the works was submitted in May 2013, it appears to have lain dormant for years, and was only approved by the PA on Monday.

Malta's neglected Fort Ricasoli to finally undergo restoration
Credit: WikiCommons

The Restoration Directorate did not respond to questions on why the plans were delayed and where they fitted in the broader strategy for conserving the fort.
Concerns over the fort’s survival have increased in recent years, and heritage group Wirt il-Kalkara last year estimated it would take €50 million worth of emergency works to ensure its survival.

Malta's neglected Fort Ricasoli to finally undergo restoration
Credit: WikiCommons

Designed by the Italian military engineer Antonio Maurizio Valperga, the fort was built between 1670 and 1698 on a promontory known as Gallows Point, commanding the entrance to the Grand Harbour. Over the centuries, it was occupied and added to by the Knights of St John, the French and, finally, the British army and Royal Navy, before being decommissioned in the 1960s, since when it has been used for industry and as a film location, including for Gladiator and Game of Thrones.

It is a Grade 1 scheduled national monument and has been on the tentative list of Unesco World Heritage Sites since 1998.

Author: Philip Leone Ganado | Source: The Times of Malta [June 22, 2019]



Mystery of ancient temple discovered at Durrës solved

The Darda Hill in Durrës (historically known as Dyrrachion), near the Brick Factory which uses the quality clay of the area, became densely populated after the 1990s. Archaeological findings, however, show that it has been populated even earlier and probably was one of the sacred places of ancient Durres. Thousands of small mature stone statues about 2600 years old were found on this hill in a massive discovery in 1970 by archaeologist Vangjel Toçi.

Mystery of ancient temple discovered at Durrës solved
Site of Epidamnos at Durres, Albania [Credit: University of Cincinnati]

The statues were gifts with the face of the temple goddess left there by the women of Dyrrachion (modern Durres) who prayed to her to protect them during birth and give them well-being. For years it was believed the shrine belonged with the goddess of passion and love to Aphrodite, but after 18 years a team of archaeologists and Albanian-French scholars came to the conclusion that the temple belongs to her rival Artemis, known as the goddess of chastity.

The events did not come just as in the Euripides Hippolytus tragedy that talks about the rivalry between the two goddesses of Olympus, but were mainly developed at a close table at one of the offices of the Institute of Archaeology in Durres, 30 years after the shrine was found by Toçi. Ten archaeologists and scholars from Albania and France, led by French archaeologist Arthur Muller and Albanian artist Fatos Tartari, bowed for years over six tons of archaeological finds, including small figurines, ceramic pieces and coins.

“It’s a great discovery and there have never been so many terracotta figures with Greek figurines found,” said Muller.

Archaeologists believe they have reached the end of their work, and the model project that studied Artemis’s shrine has left in shelves hundreds of discovered and dated objects. Many of the pottery vessels were restored and coins were cleaned and rebuilt. Archaeologist Fatos Tartari said they are conducting a survey and looking for financial support to start publishing and hopefully have their first volume at the end of the year.

Mystery of ancient temple discovered at Durrës solved
The clay figurine drawer of the Artemis goddess 
[Credit: Geri Emiri]

The first thing that has left a mark is the volume of findings which amounts to about 6 tons of archaeological objects, with 4.5 tons of pottery as the main category and 1.8 tons on figurine fragments. Tartari explained that “such a great production belongs to a highly developed, large population, in conditions when we lack accurate reports on population.”

This is just one of the answers archaeologists have received during the several year study. The team is also comprised by coin scholar Shpresa Gjongecaj, Belisa Muka who is a clay figurine researcher, Frederik Stamati who is a coin restorer, Avni Alcani who is a restorer of terracotta and figurines, archaeologist Eduard Shehi, antique art historian Marion Dufeu-Muller, Anne Tichit who is an antique ceramic researcher, and Stephanie Huyscom-Haxhi, a clay figurines researcher.

“Painted containers are reassembled. 650 coins have been mechanically and chemically cleaned. We cannot say how many pieces of ceramic or figurines have been restored because they have been in different volumes,” said Tartari.

The team also found that different from what was assumed, it was not Aphrodite who was worshipped, but Artemis. Tartari explained that they have antique texts which refer to Artemis in Durres. The ancient Appian author who wrote about the wars of Caesar and Pompeii in Durres, gives a passage that sent them to the Sanctuary of Artemis.

Mystery of ancient temple discovered at Durrës solved
Earthen figurine from the Sanctuary of Artemis 
[Credit: Geri Emiri]

Archaeologists have identified traces of the name of the goddess Artemis, who was very popular in the territory of Illyria, after restoring the inscriptions painted on the dishes dedicated to this goddess. They explain that through the restoration were found the inscriptions of Artemis that were worked in pottery and metal fragments. Objects discovered are diversified in bronze and stone. Artemis once appeared as a hunter and as a defender of the road that bound Durres with the Marsh.
Archaeologists believe that the women of the city were mainly on the shrine who, according to their social status, donated figurines made of muddy clay, in honor of the goddess Artemis, who emerged as a guarantor of well-being and marriage. Men are also believed to have donated figurines. According to archaeologists, their gifts differ as they are mostly miniature containers for keeping wine. They made the gifts after they got citizenship and tried to become part of the city’s society.

Editor’s Note

The city was originally founded by Greek colonists from Corinth and Corfu under the name of Epidamnos (Greek: Επίδαμνος) around the 7th century BC and renamed Dyrrachion during the Roman and Byzantine periods. The Via Egnatia, the continuation of the Via Appia, started in the city and led across the interior of the Balkan Peninsula to Constantinople in the east. In the Middle Ages, it was contested between Bulgarian, Venetian and Ottoman dominions.

Source: Tirana Times [June 22, 2019]



Where did the gold from the time of Stonehenge come from? Analysing the Bush Barrow...

Glittering with dazzling detail, its secrets have remained untold for thousands of years. But now the full story of this once exquisitely beautiful jewelled dagger – buried near Stonehenge two millennia before Christ – may at last be revealed.

Where did the gold from the time of Stonehenge come from? Analysing the Bush Barrow dagger
The Bush Barrow Chieftain was buried close to Stonehenge at a time when the monument
was being changed and adapted after the sarsen trilithons had been erected. Carvings
 on the sarsens show a dagger similar to the one found at Bush Barrow
[Credit: University of Birmingham/David Bukach]

The Bronze Age artefact, called the Bush Barrow dagger after the site where it was found, was discovered in the burial mound of a chieftain 200 years ago.

A watercolour painted shortly after the discovery of the dagger in 1808 showed the handle in its golden glory. However, the handle began to disintegrate within hours of being dug up and exposed to the air, with just the golden shards remaining.

Archaeologists have long puzzled over the intricate handiwork of the handle, which was inlaid with more than 140,000 studs of gold, individually barely visible to the naked eye, each a millimetre long and no more than a third of a millimetre in diameter.

The studs were glued into pre-drilled holes with tree resin and formed into zigzag patterns at an incredible density of 1,000 studs to a square centimetre.

Experts believe only children aged no more than ten would have been capable of such delicate handicraft. Straining to see such tiny details may have extracted a heavy price, leaving their eyesight ruined. Until now, the source of the gold has been unknown. But scientist Dr Christopher Standish, of Southampton University, is carrying out tests to find out the exact origin.

Where did the gold from the time of Stonehenge come from? Analysing the Bush Barrow dagger
The blade is made of bronze but the wooden pommel is one of the most remarkable Bronze Age
 finds in Britain, decorated with microscopic gold studs set in a zig-zag pattern
[Credit: University of Birmingham/David Bukach]

One stud will be bombarded with X-rays to analyse the minute quantity of lead impurities mixed with the gold to reveal a telltale signature specific to one location. It is possible the gold came from Cornwall, Wales, Ireland or Brittany.

The dagger blade and remains of the handle are on display at the Wiltshire Museum in Devizes, near Stonehenge. Museum director David Dawson said: «Our spectacular gold-studded dagger is one of the most remarkable prehistoric artefacts in the world but we have no real idea who made it, or where. There are other daggers with gold handles from the same period. Six were found in Britain and 22 in Brittany. The other British ones were pretty rubbish, while the ones from Brittany were pretty good but none of them is anything like our Bush Barrow dagger. It is likely to have come from France.»

Mr Dawson believes only someone with very severe myopia would have been able to do such intricate close-up work. He said: «There would have been Bronze Age metal workers who were left myopic for their adult life. They would have been able to see only a few inches. They would have been unable to do any other work apart from the making of tiny artefacts and would have had to be supported by the community.»

The handle is estimated to have taken at least 2,500 hours to complete in six stages. First the gold would have to be rolled into wire as thin as a human hair. One end would be flattened to form the circular head of the stud and the wire would be cut with a fine flint blade. A tiny bronze awl would have been used to drill holes in the wooden handle, which would then have been coated with sticky resin. Only then would the studs have been placed with tiny bone tweezers.

The result of the tests will be revealed in November.

Author: Simon De Bruxelles | Source: Daily Mail Online [June 23, 2019]



Climate change is taking its toll on Greek monuments, say scientists

Climate change is threatening ancient Greek monuments, among them the Acropolis, one of the most-visited archaeological sites in the world, scientists said.

Climate change is taking its toll on Greek monuments, say scientists
View of the Athenian Acropolis [Credit: Alkis Konstantinidis/Reuters]

Air pollution and acid rain are eroding marbles, while extreme weather phenomena such as droughts or torrential rains have led ancient walls and temples to develop structural problems.

Even though the Acropolis hill, where the Parthenon stands, is probably Greece’s best preserved archaeological site, there are signs that climate change has been increasingly affecting the monuments that stand on the hill.

“The walls of the (ancient) city have more erosion than in the past,” Maria Vlazaki, General Secretary in the Greek Culture Ministry, told Reuters.

The temple of the Parthenon on the rock of the Acropolis, located in the heart of Athens, dates back to the classical period of antiquity – the 5th century BC.

For decades there have been efforts to preserve and protect the Acropolis and its monuments, an operation that has been sped up since the mid 1970s. But the country has hundreds if not thousands of exposed archaeological sites.

“Every year, we have more cases… We give more money, unexpected money to protect the walls of the (ancient) cities that had no problems before, to protect the coastal area,” Vlazaki said.

The wider Athens area has been hit hard by deadly floods and forest fires over the last decade. A 2007 forest fire in the Peloponnese peninsula threatened to destroy the temples and stadiums of ancient Olympia, birthplace of the Olympic Games.

Christos Zerefos, a professor in the Academy of Athens said extreme weather events had become more frequent and the sudden swings from periods of flooding to drought were destabilizing the monuments.

Speaking on the sidelines of a conference on climate change and cultural heritage, Zerefos told Reuters Greece needed better shelter for its monuments, and a monitoring system that would help provide extra protection in case of extreme weather.

Authors: Lefteris Papadimas & Idyli Tsakiri | Source: Reuters [June 25, 2019]



The art of the Roman deal

Romans are depicted as slashing and burning their way across countries in order to secure their empire. But a University of Michigan archaeologist suggests that the Romans may have trapped more flies with honey.

The art of the Roman deal
Roman fresco from the Necropolis of Esquilino, dated c. 300-280 BC,
 depicts a handshake between a Roman and a non-Roman
[Credit: WikiCommons]

At its peak—about the year 117—the Roman Empire ringed the Mediterranean Sea, encompassing present-day Italy, Spain, France, Germany, Eastern Europe, Greece, Turkey, Syria and a swath across northern Africa. Since the Middle Ages, historians have described this expansion as a military conquest. But for all its reach, the Roman conquest yielded little evidence of warfare or a disruption of power within excavated settlements across Italy, according to author Nicola Terrenato.

Instead, Terrenato thinks that elite Roman landowners and politicians offered positions of political power to non-Roman nobles in order to woo them into their empire. A wealth of recently digitized inscriptions shows local aristocrats surviving the conquest unscathed. Some of these aristocrats even thrived as politicians in Rome.

«It seems the Romans said, ‘Come quietly and be a part of this, and you will not only preserve local power, but also have the chance to play the big game in Rome,'» said Terrenato, author of the book The Early Roman Expansion into Italy. «The violence was there, but this really wasn’t what made the Roman empire. What made the Roman empire was delicate and smart back-channel diplomacy among the landed elites.»

Terrenato’s research spans decades in the field across central Italy, most recently at Gabii. In the process, he realized that very few of the villages and farms in conquered regions reflected war-related destruction. Nor did the sites show a change in language or customs in local societies.

Had the conquest been very violent, as it is generally accepted, Terrenato argues one would expect to find evidence of disruption and radical shifts in leadership. Instead, there is strong evidence that the social and economic structures within these settlements remained the same, and the same families who were in power before the Roman expansion appeared to maintain their dominant positions. For instance, says Terrenato, family tombs of the local nobility continue long after this supposedly catastrophic event.

«Archaeological evidence allows you to see the material truth. You may have ancient historians saying that a city was sacked and destroyed, but when we excavate it, we see little destruction,» Terrenato said. «There must have been some process of negotiation by which Romans and non-Roman elites agreed on a grand bargain to rule the empire together.»

Author: Morgan Sherburne | Source: University of Michigan [June 26, 2019]



NASA Technology Missions Launched on SpaceX Falcon Heavy

NASA — Goddard Space Flight Center logo.

June 26, 2019

NASA technology demonstrations, which one day could help the agency get astronauts to Mars, and science missions, which will look at the space environment around Earth and how it affects us, have launched into space on a Falcon Heavy rocket.

The NASA missions — including the Deep Space Atomic Clock and two instruments from NASA’S Jet Propulsion Laboratory in Pasadena, California — lifted off at 11:30 p.m. PDT (2:30 a.m. EDT) Tuesday from NASA’s Kennedy Space Center in Florida, as part of the Department of Defense’s Space Test Program-2 (STP-2) launch.

Image above: A SpaceX Falcon Heavy rocket carrying 24 satellites as part of the Department of Defense’s Space Test Program-2 (STP-2) mission launches from Launch Complex 39A at NASA’s Kennedy Space Center in Florida Tuesday, June 25, 2019. The satellites include four NASA technology and science payloads that will study non-toxic spacecraft fuel, deep space navigation, «bubbles» in the electrically-charged layers of Earth’s upper atmosphere, and radiation protection for satellites. Image Credits: NASA/Joel Kowsky.

«This launch was a true partnership across government and industry, and it marked an incredible first for the U.S. Air Force Space and Missile Systems Center,» said Jim Reuter, associate administrator for NASA’s Space Technology Mission Directorate. «The NASA missions aboard the Falcon Heavy also benefited from strong collaborations with industry, academia and other government organizations.»

The missions, each with a unique set of objectives, will aid in smarter spacecraft design and benefit the agency’s Moon to Mars exploration plans by providing greater insight into the effects of radiation in space and testing an atomic clock that could change how spacecraft navigate.

With launch and deployments complete, the missions will start to power on, communicate with Earth and collect data. They each will operate for about a year, providing enough time to mature the technologies and collect valuable science data. Below is more information about each mission, including notional timelines for key milestones.

Enhanced Tandem Beacon Experiment

Two NASA CubeSats making up the Enhanced Tandem Beacon Experiment (E-TBEx) deployed at 12:08 and 12:13 a.m. PDT (3:08 and 3:13 a.m. EDT). Working in tandem with NOAA’s COSMIC-2 mission — six satellites that each carry a radio occultation (GPS) receiver developed at JPL — E-TBEx will explore bubbles in the electrically-charged layers of Earth’s upper atmosphere, which can disrupt communications and GPS signals that we rely on every day. The CubeSats will send signals in several frequencies down to receiving stations on Earth. Scientists will measure any disruptions in these signals to determine how they’re being affected by the upper atmosphere.

— One to three weeks after launch: E-TBEx operators «check out» the CubeSats to make sure power, navigation/guidance and data systems are working in space as expected.

— Approximately three weeks after launch: Science beacons that send signals to antennas on Earth power up and begin transmitting to ground stations.

— About one year after launch: The E-TBEx mission ends.

Deep Space Atomic Clock

NASA’s Deep Space Atomic Clock is a toaster oven-size instrument traveling aboard a commercial satellite that was released into low-Earth orbit at 12: 54 a.m. PDT (3:54 a.m. EDT). The unique atomic clock will test a new way for spacecraft to navigate in deep space. The technology could make GPS-like navigation possible at the Moon and Mars.

— Two to four weeks after launch: The ultra-stable oscillator, part of the Deep Space Atomic Clock that keeps precise time, powers on to warm up in space.

— Four to seven weeks after launch: The full Deep Space Atomic Clock powers on.

— Three to four months after launch: Preliminary clock performance results are expected.

— One year after full power on: The Deep Space Atomic Clock mission ends, final data analysis begins.

Green Propellant Infusion Mission

The Green Propellant Infusion Mission (GPIM) deployed at 12:57 a.m. PDT (3:57 a.m. EDT) and immediately began to power on. GPIM will test a new propulsion system that runs on a high-performance and non-toxic spacecraft fuel. This technology could help propel constellations of small satellites in and beyond low-Earth orbit.

— Within a day of launch: Mission operators check out the small spacecraft.

— One to three weeks after launch: Mission operators ensure the propulsion system heaters and thrusters are operating as expected.

— During the first three months after launch: To demonstrate the performance of the spacecraft’s thrusters, GPIM performs three lowering burns that place it in an elliptical orbit; each time GPIM gets closer to Earth at one particular point in its orbit.

— Throughout the mission: Secondary instruments aboard GPIM measure space weather and test a system that continuously reports the spacecraft’s position and velocity.

— About 12 months after launch: Mission operators command a final thruster burn to deplete the fuel tank, a technical requirement for the end of mission.

— About 13 months after launch: The GPIM mission ends.

Space Environment Testbeds

The U.S. Air Force Research Laboratory’s Demonstration and Science Experiments (DSX) was the last spacecraft to be released from STP-2 at 3:04 a.m. PDT (6:04 a.m. EDT) Onboard is an instrument designed by JPL to measure spacecraft vibrations, and four NASA experiments that make up the Space Environment Testbeds (SET). SET will study how to better protect satellites from space radiation by analyzing the harsh environment of space near Earth and testing various strategies to mitigate the impacts. This information can be used to improve spacecraft design, engineering and operations in order to protect spacecraft from harmful radiation driven by the Sun.

— Three weeks after launch: SET turns on for check out and testing of all four experiments.

— Eight weeks after launch: Anticipated start of science data collection.

— About 12 months after check-out: The SET mission ends.

In all, STP-2 delivered about two dozen satellites into three separate orbits around Earth. Kennedy Space Center engineers mentored Florida high school students who developed and built a CubeSat that also launched on STP-2.

«It was gratifying to see 24 satellites launch as one,» said Nicola Fox, director of the Heliophysics Division in NASA’s Science Mission Directorate. «The space weather instruments and science CubeSats will teach us how to better protect our valuable hardware and astronauts in space, insights useful for the upcoming Artemis program and more.»

GPIM and the Deep Space Atomic Clock are both part of the Technology Demonstration Missions program within NASA’s Space Technology Mission Directorate. The Space Communications and Navigation program within NASA’s Human Exploration and Operations Mission Directorate also provided funding for the atomic clock. SET and E-TBEx were both funded by NASA’s Science Mission Directorate.

Related article:

SpaceX — STP-2 Mission Success

Related links:

Enhanced Tandem Beacon Experiment (E-TBEx): https://www.nasa.gov/e-tbex/

NOAA’s COSMIC-2 mission: https://www.nesdis.noaa.gov/COSMIC-2

Deep Space Atomic Clock: https://www.nasa.gov/mission_pages/tdm/clock/index.html

Green Propellant Infusion Mission (GPIM): https://www.nasa.gov/mission_pages/tdm/green/index.html

Space Environment Testbeds (SET): https://www.nasa.gov/content/goddard/set-mission-overview

CubeSat: https://www.nasa.gov/feature/local-florida-high-school-shoots-for-the-stars-with-student-developed-cubesat

Artemis: https://www.nasa.gov/specials/moon2mars/#artemis

Learn more about NASA technology: https://www.nasa.gov/spacetech

Find out how NASA is sending astronaut back to the Moon and on to Mars at: https://www.nasa.gov/topics/moon-to-mars

Image (mentioned), Text, Credits: NASA/Clare Skelly/GSFC/Karen Fox/JPL/Arielle Samuelson.

Greetings, Orbiter.chArchive link

Astronomers see ‘warm’ glow of Uranus’s rings

The rings of Uranus are invisible to all but the largest telescopes — they weren’t even discovered until 1977 — but they’re surprisingly bright in new heat images of the planet taken by two large telescopes in the high deserts of Chile.

Astronomers see 'warm' glow of Uranus's rings
Composite image of Uranus’s atmosphere and rings at radio wavelengths, taken with the ALMA array in December
2017. The image shows thermal emission, or heat, from the rings of Uranus for the first time, enabling scientists to
determine their temperature: a frigid 77 Kelvin (-320 F). Dark bands in Uranus’s atmosphere at these wavelengths
show the presence of molecules that absorb radio waves, in particular hydrogen sulfide gas. Bright regions like the
 north polar spot (yellow spot at right, because Uranus is tipped on its side) contain very few of these molecules
[Credit: UC Berkeley/Edward Molter & Imke de Pater]

The thermal glow gives astronomers another window onto the rings, which have been seen only because they reflect a little light in the visible, or optical, range and in the near-infrared. The new images taken by the Atacama Large Millimeter/submillimeter Array (ALMA) and the Very Large Telescope (VLT) allowed the team for the first time to measure the temperature of the rings: a cool 77 Kelvin, or 77 degrees above absolute zero — the boiling temperature of liquid nitrogen and equivalent to 320 degrees below zero Fahrenheit.

The observations also confirm that Uranus’s brightest and densest ring, called the epsilon ring, differs from the other known ring systems within our solar system, in particular the spectacularly beautiful rings of Saturn.

«Saturn’s mainly icy rings are broad, bright and have a range of particle sizes, from micron-sized dust in the innermost D ring, to tens of meters in size in the main rings,» said Imke de Pater, a UC Berkeley professor of astronomy. «The small end is missing in the main rings of Uranus; the brightest ring, epsilon, is composed of golf ball-sized and larger rocks.»

By comparison, Jupiter’s rings contain mostly small, micron-sized particles (a micron is a thousandth of a millimeter). Neptune’s rings are also mostly dust, and even Uranus has broad sheets of dust between its narrow main rings.

Astronomers see 'warm' glow of Uranus's rings
Near-infrared image of the Uranian ring system taken with the adaptive optics system on the 10-meter Keck telescope
in Hawaii in July 2004. The image shows reflected sunlight. In between the main rings, which are composed of
centimeter-sized or larger particles, sheets of dust can be seen. The epsilon ring seen in new thermal images
is at the bottom [Credit: UC Berkeley/Imke de Pater, Seran Gibbard & Heidi Hammel, 2006]

«We already know that the epsilon ring is a bit weird, because we don’t see the smaller stuff,» said graduate student Edward Molter. «Something has been sweeping the smaller stuff out, or it’s all glomming together. We just don’t know. This is a step toward understanding their composition and whether all of the rings came from the same source material, or are different for each ring.»

Rings could be former asteroids captured by the planet’s gravity, remnants of moons that crashed into one another and shattered, the remains of moons torn apart when they got too close to Uranus, or debris remaining from the time of formation 4.5 billion years ago.

The new data were published this week in the Astronomical Journal. De Pater and Molter led the ALMA observations, while Michael Roman and Leigh Fletcher from the University of Leicester in the United Kingdom led the VLT observations.

«The rings of Uranus are compositionally different from Saturn’s main ring, in the sense that in optical and infrared, the albedo is much lower: they are really dark, like charcoal,» Molter said. «They are also extremely narrow compared to the rings of Saturn. The widest, the epsilon ring, varies from 20 to 100 kilometers wide, whereas Saturn’s are 100’s or tens of thousands of kilometers wide.»

Astronomers see 'warm' glow of Uranus's rings
Images of the Uranian ring system captured at different wavelengths by the ALMA and VLT telescopes.
The planet itself is masked since it is very bright compared to the rings [Credit: Edward Molter,
Imke de Pater, Michael Roman & Leigh Fletcher, 2019]

The lack of dust-sized particles in Uranus’s main rings was first noted when Voyager 2 flew by the planet in 1986 and photographed them. The spacecraft was unable to measure the temperature of the rings, however.

To date, astronomers have counted a total of 13 rings around the planet, with some bands of dust between the rings. The rings differ in other ways from those of Saturn.

«It’s cool that we can even do this with the instruments we have,» he said. «I was just trying to image the planet as best I could and I saw the rings. It was amazing.»

Both the VLT and ALMA observations were designed to explore the temperature structure of Uranus’ atmosphere, with VLT probing shorter wavelengths than ALMA.

«We were astonished to see the rings jump out clearly when we reduced the data for the first time,» Fletcher said.

This presents an exciting opportunity for the upcoming James Webb Space Telescope, which will be able provide vastly improved spectroscopic constraints on the Uranian rings in the coming decade.

Author: Robert Sanders | Source: University of California — Berkeley [June 20, 2019]



Lethal plastic trash now common in Greece’s whales

A study of whales and dolphins that have washed up dead in Greece over a 20-year period has found alarmingly high levels of plastic trash—mostly bags—in the animals’ stomachs, which can condemn them to a slow and painful death.

Lethal plastic trash now common in Greece's whales
In this undated handout photo provided by the Pelagos Cetacean Research Institute on Friday, June 21, 2019, researchers
 Alexandros Frantzis and Voula Alexiadou lie on a tennis court next to the plastic that was in the stomach of a dead
sperm whale found on the Aegean Sea island of Mykonos. The collection includes a Greek souvlaki restaurant bag,
Turkish trash bags and biscuit packaging. A study of whales and dolphins that have washed up dead in
Greece over a 20-year period has found alarmingly high levels of plastic trash — mostly bags —
in the animals’ stomachs, which can condemn them to a slow and painful death
[Credit: Pelagos Cetacean Research Institute via AP]

In the worst case, a researcher said Friday, a 5.3-meter (17-foot) young sperm whale beached on the Aegean island of Mykonos had swallowed 135 plastic items weighing a total of 3.2 kilograms (7 pounds). This blocked its stomach, grossly distending it, while the animal itself was emaciated and had starved to death.

Sperm whales are an endangered species already at high risk in the Mediterranean from deadly collisions with ships, entanglement in drift fishing nets and noise pollution from oil and gas exploration.

The study published in the Marine Pollution Bulletin, which organizers say was the first on such a scale in the Mediterranean, found that sperm whales were also the species worst affected by plastic ingestion. Six out of ten specimens were found to have consumed plastics according to Alexandros Frantzis, scientific director of the Athens-based Pelagos Cetacean Research Institute that conducted the research.

«The amount of (debris) we found is very high, and should set off an alarm,» he told The Associated Press. «It is now something common. … It’s not just that some random animal swallowed plastic.»

Frantzis is a prominent whale and dolphin expert known for first linking fatal whale beachings to the use of military sonar by warships.

In a separate incident outside the scope of the Greek study, an 8-meter (26-foot) pregnant sperm whale was found dead off Sardinia in March with 22 kilograms (48.5 pounds) of plastic in its stomach.

The study, which did not examine microplastics that are invisible to the naked eye, found that nine out of 34 whales, porpoises and dolphins washed up dead on Greek shores from 1993-2014 had swallowed plastic debris of considerable size. Three died from it.

Frantzis said bags pose a huge problem because, while not more lethal than other plastic items, they are so widely used.

«None of us is innocent,» he said. «Without our knowledge or intent, some of (the plastic that is swallowed by whales or dolphins) may have passed through our hands. We may even have disposed of it in the trash, and it may have been blown away from an open landfill. These things travel, they have no borders.»

The Mediterranean is one of the most polluted seas in the world in terms of both floating and seabed debris, with plastic the main problem—found even in abyssal depths. The World Wide Fund for Nature and Greenpeace have both expressed grave concern.

Frantzis said the solution is to stop the «crazy and useless» production of plastic.

«Don’t buy, don’t use (it) and exert pressure to stop the production,» he said.

Author: Nicholas Paphitis | Source: The Associated Press [June 21, 2019]



The Lagoon Nebula This colorful image, taken by our Hubble Space…

The Lagoon Nebula 

This colorful image, taken by our Hubble Space Telescope between Feb. 12 and Feb. 18, 2018 , celebrated the Earth-orbiting observatory’s 28th anniversary of viewing the heavens, giving us a window seat to the universe’s extraordinary tapestry of stellar birth and destruction.

At the center of the photo, a monster young star 200,000 times brighter than our Sun is blasting powerful ultraviolet radiation and hurricane-like stellar winds, carving out a fantasy landscape of ridges, cavities, and mountains of gas and dust.

This region epitomizes a typical, raucous stellar nursery full of birth and destruction. The clouds may look majestic and peaceful, but they are in a constant state of flux from the star’s torrent of searing radiation and high-speed particles from stellar winds. As the monster star throws off its natal cocoon of material with its powerful energy, it is suppressing star formation around it.

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Cluster Merger: Galaxy Clusters Caught in a First Kiss

This image show the separate galaxy clusters 1E2215 and 1E2216, located about 1.2 billion light years from Earth, captured as they enter a critical phase of merging. Chandra’s X-ray data were combined with a radio image from the Giant Metrewave Radio Telescope in India and an optical image from the Sloan Digital Sky Survey that shows galaxies and stars in the field of view.  Credit: X-ray: NASA/CXC/RIKEN/L. Gu et al; Radio: NCRA/TIFR/GMRT; Optical: SDSS 

For the first time, astronomers have found two giant clusters of galaxies that are just about to collide, as reported in a new press release by RIKEN. This observation is important in understanding the formation of structure in the Universe, sincelarge-scale structures—such as galaxies and clusters of galaxies—are thought to grow by collisions and mergers.

The composite image shows the separate galaxy clusters 1E2215 and 1E2216, located about 1.2 billion light years from Earth, captured as they enter a critical phase of merging. Chandra’s X-ray data (blue) have been combined with a radio image from the Giant Metrewave Radio Telescope in India (red). These images were then overlaid on an optical image from the Sloan Digital Sky Survey that shows galaxies and stars in the field of view.

The discovery of 1E2215 and 1E2216 at this stage of merging has enabled astronomers to test their computer simulations of these important collisions. This new result provides evidence of a shock wave that is generated early in the merging process and travels out away from the collision in a perpendicular direction.

Because the merging process takes much longer than a human lifetime, astronomers only see snapshots of the various stages of these collisions. A separate graphic shows 1E2215 and 1E2216, plus two systems at earlier stages before collision (Abell 399/Abell 401, and Abell 1758), and one where the collision has already occurred (CIZA J2242.8). This series of images represents the sequential steps a galaxy cluster would undergo. A labeled version shows the separation between the two clusters and the amount of time, measured in billions of years, before or after impact.

In this cluster sequence graphic, only X-ray and radio data are shown. For Abell 399 and Abell 401, the X-ray data are from ROSAT and the radio data are from GMRT. In the Abell 1758 image and the 1E2215 and 1E2216 image, the X-ray are from Chandra and the radio data come from GMRT. Finally, the X-ray data in CIZA J2242.8 are from ESA’s XMM-Newton, while the radio data are from the Westerbork Synthesis Radio Telescope in the Netherlands. Credit: X-ray: NASA/CXC/RIKEN/L. Gu et al; Radio: NCRA/TIFR/GMRT; Optical: SDSS

Clusters of galaxies are the largest known objects held together by gravity and consist of hundreds of galaxies that each contain hundreds of billions of stars. Ever since the Big Bang, these objects have been growing by colliding and merging with each other. Due to their large size, with diameters of a few million light years, these collisions can take about a billion years to complete. After the dust has settled, the two colliding clusters will have merged into one bigger cluster.

The result was published in Nature Astronomy on June 24, 2019, by first author Liyi Gu of the RIKEN national science institute in Japan and the SRON Netherlands Institute for Space Research and collaborators. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations.

Fast Facts for Cluster Merger:

Scale: About 30 arcmin across (10 million light years)
Category: Groups & Clusters of Galaxies
Coordinates (J2000): RA 22h 18m 20.3s | Dec -03° 49′ 41″
Constellation: Aquarius
Observation Date: 5 pointings from July 23 to July 29, 2018
Observation Time: 40 hours (1 day 16 hours)
Obs. ID: 21131-21134, 20778
Instrument: ACIS
References: Gu, L. et al., 2019, Nature Astronomy, in press
Color Code: X-ray: Blue; Radio: Pink; Optical: Red, Green, Blue
Distance Estimate: About 1.2 billion light years (z=0.09)

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Hubble Finds Tiny “Electric Soccer Balls” in Space, Helps Solve Interstellar Mystery

NASA — Hubble Space Telescope patch.

June 25, 2019

Scientists using NASA’s Hubble Space Telescope have confirmed the presence of electrically-charged molecules in space shaped like soccer balls, shedding light on the mysterious contents of the interstellar medium (ISM) – the gas and dust that fills interstellar space.

Image above: This is an artist’s concept depicting the presence of buckyballs in space. Buckyballs, which consist of 60 carbon atoms arranged like soccer balls, have been detected in space before by scientists using NASA’s Spitzer Space Telescope. The new result is the first time an electrically charged (ionized) version has been found in the interstellar medium. Image Credits: NASA/JPL-Caltech.

Since stars and planets form from collapsing clouds of gas and dust in space, “The diffuse ISM can be considered as the starting point for the chemical processes that ultimately give rise to planets and life,” said Martin Cordiner of the Catholic University of America, Washington. “So fully identifying its contents provides information on the ingredients available to create stars and planets.” Cordiner, who is stationed at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, is lead author of a paper on this research published April 22nd in the Astrophysical Journal Letters.

The molecules identified by Cordiner and his team are a form of carbon called “Buckminsterfullerene,” also known as “Buckyballs,” which consists of 60 carbon atoms (C60) arranged in a hollow sphere. C60 has been found in some rare cases on Earth in rocks and minerals, and can also turn up in high-temperature combustion soot.

C60 has been seen in space before. However, this is the first time an electrically charged (ionized) version has been confirmed to be present in the diffuse ISM. The C60 gets ionized when ultraviolet light from stars tears off an electron from the molecule, giving the C60 a positive charge (C60+). “The diffuse ISM was historically considered too harsh and tenuous an environment for appreciable abundances of large molecules to occur,” said Cordiner. “Prior to the detection of C60, the largest known molecules in space were only 12 atoms in size. Our confirmation of C60+ shows just how complex astrochemistry can get, even in the lowest density, most strongly ultraviolet-irradiated environments in the Galaxy.”

Life as we know it is based on carbon-bearing molecules, and this discovery shows complex carbon molecules can form and survive in the harsh environment of interstellar space. “In some ways, life can be thought of as the ultimate in chemical complexity,” said Cordiner. “The presence of C60 unequivocally demonstrates a high level of chemical complexity intrinsic to space environments, and points toward a strong likelihood for other extremely complex, carbon-bearing molecules arising spontaneously in space.”

Most of the ISM is hydrogen and helium, but it’s spiked with many compounds that haven’t been identified. Since interstellar space is so remote, scientists study how it affects the light from distant stars to identify its contents. As starlight passes through space, elements and compounds in the ISM absorb and block certain colors (wavelengths) of the light. When scientists analyze starlight by separating it into its component colors (spectrum), the colors that have been absorbed appear dim or are absent. Each element or compound has a unique absorption pattern that acts as a fingerprint allowing it to be identified. However, some absorption patterns from the ISM cover a broader range of colors, which appear different from any known atom or molecule on Earth. These absorption patterns are called Diffuse Interstellar Bands (DIBs). Their identity has remained a mystery ever since they were discovered by Mary Lea Heger, who published observations of the first two DIBs in 1922.

Hubble Space Telescope (HST). Animation Credits: NASA/ESA

A DIB can be assigned by finding a precise match with the absorption fingerprint of a substance in the laboratory. However, there are millions of different molecular structures to try, so it would take many lifetimes to test them all.

“Today, more than 400 DIBs are known, but (apart from the few newly attributed to C60+), none has been conclusively identified,” said Cordiner. “Together, the appearance of the DIBs indicate the presence of a large amount of carbon-rich molecules in space, some of which may eventually participate in the chemistry that gives rise to life. However, the composition and characteristics of this material will remain unknown until the remaining DIBs are assigned.”

Decades of laboratory studies have failed to find a precise match with any DIBs until the work on C60+. In the new work, the team was able to match the absorption pattern seen from C60+ in the laboratory to that from Hubble observations of the ISM, confirming the recently claimed assignment by a team from University of Basel, Switzerland, whose laboratory studies provided the required C60+ comparison data. The big problem for detecting C60+ using conventional, ground-based telescopes, is that atmospheric water vapor blocks the view of the C60+ absorption pattern. However, orbiting above most of the atmosphere in space, the Hubble telescope has a clear, unobstructed view. Nevertheless, they still had to push Hubble far beyond its usual sensitivity limits to stand a chance of detecting the faint fingerprints of C60+.

The observed stars were all blue supergiants, located in the plane of our Galaxy, the Milky Way. The Milky Way’s interstellar material is primarily located in a relatively flat disk, so lines of sight to stars in the Galactic plane traverse the greatest quantities of interstellar matter, and therefore show the strongest absorption features due to interstellar molecules.

The detection of C60+ in the diffuse ISM supports the team’s expectations that very large, carbon-bearing molecules are likely candidates to explain many of the remaining, unidentified DIBs. This suggests that future laboratory efforts measure the absorption patterns of compounds related to C60+, to help identify some of the remaining DIBs.

The team is seeking to detect C60+ in more environments to see just how widespread buckyballs are in the Universe. According to Cordiner, based on their observations so far, it seems that C60+ is very widespread in the Galaxy.

This work was funded by NASA under a grant from the Space Telescope Science Institute. The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C. NASA is exploring our Solar System and beyond, uncovering worlds, stars, and cosmic mysteries near and far with our powerful fleet of space and ground-based missions.

Related links:

Astrobiology: https://www.nasa.gov/content/the-search-for-life

Hubble Space Telescope (HST): https://www.nasa.gov/mission_pages/hubble/main/index.html

Goddard Space Flight Center (GSFC): https://www.nasa.gov/centers/goddard/home/index.html

Image (mentioned), Animation (mentioned), Text, Credits: NASA/GSFC/Bill Steigerwald.

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Blakeley Raise Prehistoric Stone Circle, nr Whitehaven, Lake District, 22.6.19.

Blakeley Raise Prehistoric Stone Circle, nr Whitehaven, Lake District, 22.6.19.

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Unusual Roman wooden arm found during Northamptonshire excavation

During OA East’s most recent excavations at Warth Park, in Raunds, Northamptonshire, a very surprising discovery was made, in the form of an unusual wooden artefact.

Unusual Roman wooden arm found during Northamptonshire excavation
The arm — seen from all angles — was found in a waterlogged Roman well
[Credit: © Michael Bamforth]

This object appears to have been thrown into a Roman well, probably as a votive offering, and is a representation of a complete human arm, with an open right hand. The wooden arm was analysed by archaeological wood specialist, Michael Bamforth (University of York).
In his report, he said that it had been finely carved from a single branch, which makes use of a natural curve to form the elbow, and is very well made, as no tool marks are visible on its surface. The hand is also relatively slender and gracile and so, if it’s a life-sized piece, it seems to mimic the arm and hand of a small adult or adolescent.

Unusual Roman wooden arm found during Northamptonshire excavation
Archaeologist and wood expert Michael Bamforth examined the arm found
at the bottom of the well [Credit: Oxford Archaeology East]

Intriguingly, the upper end of the object has no trace of any jointing, or other methods that could be used to attach the arm to a larger sculpture. Therefore, it seems likely that it was just this specific element of the body, which was represented and singled as being in some way significant for votive deposition.
A small fragment from the sculpture has now been radiocarbone dated, indicating that the object dates to the earlier Roman period, specifically cal AD 86-240, which also corresponds with the date of Roman pottery recovered from waterlogged deposits in the well.

Unusual Roman wooden arm found during Northamptonshire excavation
The dig was being carried out ahead of further development of the Warth Park
 industrial estate [Credit: Oxford Archaeology East]

Significantly, although carved wooden body parts deposited as votive offerings are known from the continent, none of the examples date from the same period as that from Warth Park. Given this, this wooden arm represents an incredibly rare artefact that holds at least national, and perhaps even international, importance.

Source: Oxford Archaeology [June 20, 2019]




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