вторник, 3 декабря 2019 г.

Astronomers Propose a Novel Method of Finding Atmospheres on Rocky Worlds

This artist’s impression shows a rocky exoplanet with a wispy, cloudy atmosphere orbiting a red dwarf star. Astronomers have identified a new method that could allow Webb to detect an exoplanet’s atmosphere in just a few hours of observing time. Credits: L. Hustak and J. Olmsted (STScI)

When NASA’s James Webb Space Telescope launches in 2021, one of its most anticipated contributions to astronomy will be the study of exoplanets — planets orbiting distant stars. Among the most pressing questions in exoplanet science is: Can a small, rocky exoplanet orbiting close to a red dwarf star hold onto an atmosphere?

In a series of four papers in the Astrophysical Journal, a team of astronomers proposes a new method of using Webb to determine whether a rocky exoplanet has an atmosphere. The technique, which involves measuring the planet’s temperature as it passes behind its star and then comes back into view, is significantly faster than more traditional methods of atmospheric detection like transmission spectroscopy.

“We find that Webb could easily infer the presence or absence of an atmosphere around a dozen known rocky exoplanets with less than 10 hours of observing time per planet,” said Jacob Bean of the University of Chicago, a co-author on three of the papers.

Astronomers are particularly interested in exoplanets orbiting red dwarf stars for a number of reasons. These stars, which are smaller and cooler than the Sun, are the most common type of star in our galaxy. Also, because a red dwarf is small, a planet passing in front of it will appear to block a larger fraction of the star's light than if the star were larger, like our Sun. This makes the planet orbiting a red dwarf easier to detect through this "transit" technique.

Red dwarfs also produce a lot less heat than our Sun, so to enjoy habitable temperatures, a planet would need to orbit quite close to a red dwarf star. In fact, to be in the habitable zone — the area around the star where liquid water could exist on a planet's surface — the planet has to orbit much closer to the star than Mercury is to the Sun. As a result, it will transit the star more frequently, making repeated observations easier.

But a planet orbiting so close to a red dwarf is subjected to harsh conditions. Young red dwarfs are very active, blasting out huge flares and plasma eruptions. The star also emits a strong wind of charged particles. All of these effects could potentially scour away a planet’s atmosphere, leaving behind a bare rock.

“Atmospheric loss is the number one existential threat to the habitability of planets,” said Bean.

Another key characteristic of exoplanets orbiting close to red dwarfs is central to the new technique: They are expected to be tidally locked, meaning they have a permanent dayside and nightside. As a result, we see different phases of the planet at different points in its orbit. When it crosses the face of the star, we see only the planet’s nightside. But when it is about to cross behind the star (an event known as a secondary eclipse), or is just emerging from behind the star, we can observe the dayside.

If a rocky exoplanet lacks an atmosphere, its dayside would be very hot, just as we see with the Moon or Mercury. However if a rocky exoplanet has an atmosphere, the presence of that atmosphere is expected to lower the dayside temperature that Webb would measure. It could do this in two ways. A thick atmosphere could transport heat from the dayside to the nightside through winds. A thinner atmosphere could still host clouds, which reflect a portion of the incoming starlight thereby lowering the temperature of the planet's dayside.

“Whenever you add an atmosphere, you’re going to lower the temperature of the dayside. So if we see something cooler than bare rock, we would infer it’s likely a sign of an atmosphere,” explained Daniel Koll of the Massachusetts Institute of Technology (MIT), the lead author on two of the papers.

Webb is ideally suited for making these measurements because it has a much larger mirror than other telescopes such as NASA's Hubble or Spitzer space telescopes, which allows it to collect more light, and it can target the appropriate infrared wavelengths.

The team’s calculations show that Webb should be able to detect the heat signature of a planet's atmosphere in one to two secondary eclipses – just a few hours of observing time. In contrast, detecting an atmosphere through spectroscopic observations would typically require eight or more transits for these same planets.

Transmission spectroscopy, which studies starlight filtered through the planet’s atmosphere, also suffers from interference due to clouds or hazes, which can mask the molecular signatures of the atmosphere. In that case the spectral plot, rather than showing pronounced absorption lines due to molecules, would be essentially flat.

“In transmission spectroscopy, if you get a flat line, it doesn’t tell you anything. The flat line could mean the universe is full of dead planets that don’t have an atmosphere, or that the universe is full of planets that have a whole range of diverse, interesting atmospheres, but they all look the same to us because they’re cloudy,” said Eliza Kempton of the University of Maryland, a co-author on three of the papers.

“Exoplanet atmospheres without clouds and hazes are like unicorns – we just haven’t seen them yet, and they may not exist at all,” she added.

The team emphasized that a cooler than expected dayside temperature would be an important clue, but it would not absolutely confirm an atmosphere exists. Any remaining doubts about the presence of an atmosphere can be ruled out with follow-up studies using other methods like transmission spectroscopy.

The new technique’s true strength will be in determining what fraction of rocky exoplanets likely have an atmosphere. Approximately a dozen exoplanets that are good candidates for this method were detected during the past year. More are likely to be found by the time Webb is operational.

The Transiting Exoplanet Survey Satellite, or TESS, is finding piles of these planets,” stated Kempton.

The secondary eclipse method has one key limitation: it works best on planets that are too hot to be located in the habitable zone. However, determining whether or not these hot planets host atmospheres holds important implications for habitable-zone planets.

“If hot planets can hold onto an atmosphere, cooler ones should be able to at least as well,” said Koll.

The James Webb Space Telescope will be the world's premier space science observatory when it launches in 2021. Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it. Webb is an international project led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.




Contact:

Christine Pulliam
Space Telescope Science Institute, Baltimore, Maryland
410-338-4366
cpulliam@stsci.edu



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* This article was originally published here

Assessment of Gallo-Roman necropolis unearthed in Paris


After two years of work, the National Institute for Preventive Archaeological Research (Inrap) have presented an assessment of the excavations carried out on the site of the Gallo-Roman necropolis discovered in 2017 in Nanterre, between boulevard Joliot-Curie and rue Sadi-Carnot in the Hauts-de-Seine department, the western suburbs of Paris.

Assessment of Gallo-Roman necropolis unearthed in Paris
Three tombs carved directly into the limestone bedrock
found at the site [Credit: DR]
The first conclusion of this presentation organized by the Nanterre Historical Society is that the necropolis is older than expected. "It was first estimated to date back to a period of the Late Empire between the 3rd and 5th centuries, but it is likely that the site was occupied as early as the 1st century," said Jacques Legriel, the archaeologist who conducted the excavations.

A total of 73 graves, including 28 graves of children, were found on the site. Of these 53 graves yielded human remains that archaeologists were able to study in some detail.


Biometric and anthropological analyses have made it possible, for example, to determine the sex of 17 individuals (11 men and six women).

"The skeletons are more or less well preserved," says Jacques Legriel. "Some of them have no skull or rib cage left. In the case of the infants, the graves are empty because the children's bones did not survive the passage of time."

To refine their research, Inrap experts also subjected the remains unearthed during the excavations - such as ceramics, bone hairpins or ancient coins - to a series of analyses, such as carbon-14 dating or biochemical examination.

"In one bowl, for example, traces of dairy products and castor oil were found, and in another traces of linseed oil, and in a pitcher, red wine and conifer resin", says Jacques Legriel.


Based on this precise information, Inrap is gradually reconstructing the history of this necropolis, which has become "one of the reference sites in western Paris", according to Jacques Legriel.

The absence of jewellery and the scarcity of accompanying grave goods, for example, suggests that the site was occupied by a modest population.

"It's exciting," says Alain Bocquet, a passionate speaker at the Nanterre historical society. "Slowly, the puzzle is being put together again after the discoveries of the city of Paris in the Chemin-de-l'Ile and those of the Merovingian era, near the cathedral of Sainte-Genevieve."

"The problem is that each excavation reveals not only treasures but also a lot of disappointment," says Alain Bocquet. "The archaeologists would have destroyed two or three buildings there to see what was underneath."

Source: Le Parisien [trsl. TANN, November 20, 2019]



* This article was originally published here

Antiquities dealer charged with trafficking in Cambodian artifacts


Investigators have charged Douglas A. J. Latchford, a leading expert on Khmer antiquities, with smuggling looted Cambodian relics and helping to sell them on the international art market by concealing their tainted histories with falsified documentation.

Antiquities dealer charged with trafficking in Cambodian artifacts
A 10th-century sandstone statue, known as the Duryodhana, that was returned
to Cambodia [Credit: U.S. Attorney's Office, via AFP — Getty Images]
In a federal indictment unsealed Wednesday, Latchford, 88, was accused of having served for decades as a “conduit” for Cambodian antiquities that had been excavated illegally from ancient jungle temples during unrest in the country starting in the mid-1960s, with the beginnings of the Cambodian civil war.

According to a news release from the U.S. Attorney’s Office for the Southern District of New York, Latchford, a dual citizen of Thailand and the United Kingdom, falsified invoices and shipping documents to make it easier to sell those looted artifacts to major auction houses, dealers and museums.


The prosecutors presented in its court papers a sordid and alternative perspective on Latchford, who had been hailed in Cambodia as a protector of the country’s relics, having donated rare artifacts and money to the national museum in Phnom Penh. In 2008, he was honored with the country’s equivalent of a knighthood. He is also the co-author of three books — “Adoration and Glory: The Golden Age of Khmer Art,” “Khmer Gold” and “Khmer Bronzes” — that are foundational reference works for experts.

The U.S. government officials depicted him instead as a major player in a transnational criminal network dealing in cultural property who started supplying Western institutions and private collectors with looted antiquities as long ago as the 1970s.

Latchford could not be reached for comment Wednesday. An aide who answered his phone in Thailand said Latchford is in ill health and has been hospitalized in Bangkok for several months.

The indictment charges Latchford with conspiracy to commit wire fraud and smuggling, among other charges, the most serious of which each carry a maximum sentence of 20 years in prison. A spokesman for the U.S. attorney’s office, Nicholas Biase, declined to comment on whether an extradition request for Latchford would be made.

Antiquities dealer charged with trafficking in Cambodian artifacts
Douglas A. J. Latchford, who was once honored by the Cambodian government for donating Khmer Empire antiquities
 to the national museum, has been charged in the United States with trafficking in looted relics
[Credit: Tang Chhin Sothy/Agence France-Presse — Getty Images]
They detailed in their news release his involvement with high-profile cases such as that of a major antiquity that was withdrawn from an auction at Sotheby’s in 2011 when a Cambodian official complained that the object had been looted. The artifact, a 500-pound, 10th-century sandstone statue of a mythic warrior, known as Duryodhana, is thought to have been looted from a temple in a Cambodian jungle. Prosecutors said that Latchford exported the stone figure from Cambodia in 1972, but when Sotheby’s was seeking to verify the provenance of the artifact, Latchford told the auction house that he had the statue in London in 1970 — then changed his story to claim that he had never owned it at all.

Sotheby’s and its consignor agreed to return the Duryodhana to Cambodia after a court battle in which the U.S. government sided with Cambodia.

In 2013, the Metropolitan Museum of Art also agreed to return two statues from the same site after Cambodian officials presented evidence that they had been smuggled out of the country during the tumult of civil war in the 1970s. The statues had arrived at the museum in four separate pieces — two heads and two torsos — in a series of gifts between 1987 and 1992. Latchford was the donor or part-donor for three of them.


For years Latchford has been a character at the margins of the government’s investigation of looting in Southeast Asia. In 2016, he was mentioned in a federal criminal complaint as an unindicted co-conspirator who had helped a prominent New York gallery owner falsify documents associated with Cambodian artifacts so that they would be easier to sell on the international art market. But this is the first time that he has been formally charged.

Geoffrey S. Berman, the U.S. attorney in Manhattan, said Latchford had “built a career out of the smuggling and illicit sale of priceless Cambodian antiquities, often straight from archaeological sites.”

Tess Davis, an expert on Cambodian antiquities law, said “the name Douglas Latchford casts a long shadow” over the fate of Khmer treasures that have been smuggled and sold abroad since the Vietnam War era.

Antiquities dealer charged with trafficking in Cambodian artifacts
Looted Cambodian art for sale by Douglas Latchford
[Credit: U.S. Attorney's Office]
“As we are seeing today in Iraq and Syria, a generation ago in Cambodia, brutal civil war led to the wholesale plunder of a great ancient civilization,” Davis said.


Prosecutors describe Latchford as having provided invoices that misrepresented identifying details of artifacts, such as age or country of origin, to U.S. Customs and Border Protection in order to hide the fact that they were looted.

“Frequently, Mr. Latchford listed the ‘country of origin’ as ‘Great Britain’ or ‘Laos,’ rather than Cambodia,” the news release said, “and often described the objects as ‘figures’ from the 17th or 18th century” rather than dating to the Khmer Empire, which ended in the 15th century.

He is also accused of directing others to create false provenance documents for him.

In previous interviews, Latchford has denied any wrongdoing, defending his collecting practices as the norm at a time when there were lower standards for provenance and sales documents associated with cultural treasures. In 2012, when the U.S. government had tied him to the transportation of the Duryodhana, he said that Westerners like him who had acquired Southeast Asian relics amid the wars in Cambodia and Vietnam should be seen as having rescued objects that might have otherwise been destroyed or forgotten.

“If the French and other Western collectors had not preserved this art, what would be the understanding of Khmer culture today?” he said.

Authors: Julia Jacobs and Tom Mashberg | Source: New York Times [November 28, 2019]



* This article was originally published here

Rare box-shaped Viking brooch found in Northeastern Estonia


A fully preserved early Viking-era brooch found in Northeastern Estonia this spring is one of two such items that have been discovered in Estonia.

Rare box-shaped Viking brooch found in Northeastern Estonia
Rare early Viking box brooch found
in Estonia [Credit: BNS]
It is believed to have belonged to a woman born on the island of Gotland who moved to present-day Estonian territory later on in her life.

The bronze box-shaped brooch was found in the Ida-Viru County village of Varja.

Mauri Kiudsoo, archaeologist and keeper of the archaeological research collection at Tallinn University (TLÜ), told BNS that the brooch found at Varja was cast as a single piece.


The decorative item has been wholly preserved, with only slight damage to the surface, likely as a result of the cultivation of land, Kiudsoo said. The pin, which was apparently made of steel, is also missing.

The technical execution of the brooch is indicative of the earlier Viking era, he added.

According to Indrek Jets, a researcher familiar with the period's ornament styles, the animal ornament on the brooch represents the so-called Broa style, allowing for it to be dated to the end of the 8th or the 9th century.

The brooch was found on the fringes of a former wetland, where a lone farmstead was likely located during the Viking era.


Kiudsoo explained that the village of Varja is situated in the northeastern part of the ancient parish of Askälä, and that this region on Estonia's northern coast, between Purtse River and the present-day city of Kohtla-Järve, stands out for its exceptionally rich archaeological find material. The Eastern Route, an important Viking-era trade route, ran along Estonia's northern coast.

The archaeologist said that he believes that the brooch found at Varja belonged to a woman born on the island of Gotland, who took up residence in the Viru region of Estonia later in her life. Supporting this hypothesis is the fact that similar decorative items were in widespread use in Gotland during the Viking era, but are not common elsewhere. Kiudsoo said that hundreds of box-shaped brooches like the one recently found in Estonia have been found in Gotland.

Unlike items belonging to warriors, women's decorative items of Scandinavian origin are rarely found in Estonia. The only box-shaped brooch found here to date, which was found in Kasari in Western Estonia, has yet to be handed over to the Heritage Board. Unlike the item found in Varja, this brooch can be dated to the later period of the Viking era.

Source: ERR News [November 28, 2019]



* This article was originally published here

Three 3,500-year-old painted wooden coffins unearthed in Egypt's Luxor


Egyptian authorities on Wednesday confirmed the latest archaeological discovery to come from the ancient city of Luxor— three painted wooden coffins bearing hieroglyphic writings.

Three 3,500-year-old painted wooden coffins unearthed in Egypt's Luxor
The face on the coffin of Rao [Credit: Egypt. Ministry of Antiquities]


"The coffins are dated to 18th dynasty (1550-1295 BC) and are in a good state of conservation," said the head of Egypt's Supreme Council of Antiquities, Mostafa Waziri. "They bear coloured scenes and inscriptions," he was quoted by the local Luxor Times as saying.

Three 3,500-year-old painted wooden coffins unearthed in Egypt's Luxor
Uninscribed coffin with white colouring and brown columns, side view
[Credit: Egypt. Ministry of Antiquities]


A team of French archaeologists unearthed the coffins from the necropolis of al-Asasif, on the west bank of the Nile. Last month, Egyptian authorities announced a find of 30 wooden coffins on the same Luxor site, but the objects discovered in October were 500 years younger than the most recent find.

Three 3,500-year-old painted wooden coffins unearthed in Egypt's Luxor
The coffin of Rao, side view [Credit: Egypt. Ministry of Antiquities]


According to Egyptian official Fathy Yassin, the first of the three newly discovered coffins "belongs to a woman called 'Ti Abo' and measures 195 cm (6 feet 5 inches) in length bearing coloured scenes and hieroglyph inscription."

Three 3,500-year-old painted wooden coffins unearthed in Egypt's Luxor
The coffin of Rao, front view [Credit: Egypt. Ministry of Antiquities]
"The second coffins belongs to a woman called 'Rau' and it measures 190 cm in length," he added. The last object is smaller than the other two (180) and covered in gypsum, but has no inscriptions, according to the authorities. The gender of the occupant was not immediately clear.

Egypt has announced a series of sensational discoveries in recent months, in what is seen as a push to renew its troubled tourism industry. On Saturday, the antiquities ministry announced a find of mummified animals near Cairo, including sacred birds and predators believed to be lion cubs.

Author: Darko Janjevic | Source: Deutsche Welle [November 28, 2019]



* This article was originally published here

2019 December 3 M27: The Dumbbell Nebula Image Credit &...



2019 December 3

M27: The Dumbbell Nebula
Image Credit & Copyright: Steve Mazlin

Explanation: Is this what will become of our Sun? Quite possibly. The first hint of our Sun’s future was discovered inadvertently in 1764. At that time, Charles Messier was compiling a list of diffuse objects not to be confused with comets. The 27th object on Messier’s list, now known as M27 or the Dumbbell Nebula, is a planetary nebula, the type of nebula our Sun will produce when nuclear fusion stops in its core. M27 is one of the brightest planetary nebulae on the sky, and can be seen toward the constellation of the Fox (Vulpecula) with binoculars. It takes light about 1000 years to reach us from M27, featured here in colors emitted by hydrogen and oxygen. Understanding the physics and significance of M27 was well beyond 18th century science. Even today, many things remain mysterious about bipolar planetary nebula like M27, including the physical mechanism that expels a low-mass star’s gaseous outer-envelope, leaving an X-ray hot white dwarf.

∞ Source: apod.nasa.gov/apod/ap191203.html



* This article was originally published here

3000-year-old burial of female warrior unearthed in Armenia


The remains of an early female warrior were found in the north of Armenia, International Journal of Osteoarchaeology reported.

3000-year-old burial of female warrior unearthed in Armenia
The female warrior was in her 20s when she died and was buried with a 'rich inventory of goods'
including jewellery, experts confirmed [Credit: Khudaverdyan et al. 2019]


The remains unearthed in Tomb N 17 belonged to a woman who seemed to live as a professional warrior and was buried as an individual of rank, the results of the excavations show. The archaeologists suggested that she died in battle around 2,600 years ago. The researchers led by Anahit Khudaverdyan discovered the remains in the in Bover I necropolis in Lori province.

3000-year-old burial of female warrior unearthed in Armenia
Her injuries suggest she was struck in the pelvis by a sword and died in battle
[Credit: Khudaverdyan et al. 2019]


“Exploration of the weapon‐related traumas on human remains allows us to reconstruct the episodes of violence. This paper is an attempt of reconstructing the life and death of a female buried in the Early Armenian necropolis of Bover I (Shnogh, Lori province) based on a multidisciplinary approach integrating archaeological, written and paleopathological data derived from the skeletal analysis,” the abstract of the research reads.

3000-year-old burial of female warrior unearthed in Armenia
Archaeologists also discovered injuries to her thigh likely caused by a long-range weapon
[Credit: Khudaverdyan et al. 2019]
“During our work we identified a rich array of traumatic lesions, which shed light on her daily activities, occupation and warfare practice. We also analyzed a trapped metal arrowhead in her femur. For this region projectile injury to bone, induced by an arrow wound, strongly suggests interpersonal aggression. The same individual also suffered blows to the pelvic bone, femur and tibia. This tomb is the second burial discovered in Armenia that provides evidence on female warriors.”

Source: News Armenia [November 29, 2019]



* This article was originally published here

The Roman Temple of Mithras, Carrawburgh Roman Fort, Hadrian’s Wall, Hexham, 30.11.19.

The Roman Temple of Mithras, Carrawburgh Roman Fort, Hadrian’s Wall, Hexham, 30.11.19.



* This article was originally published here

Magnificent thermal baths in Pompeii unveiled


Magnificent thermal baths designed to be the jewel of Pompeii but destroyed by a volcanic eruption before they could be completed opened to visitors for the first time on Monday after a painstaking excavation.

Magnificent thermal baths in Pompeii unveiled
A general view shows Pompeii's thermal baths
[Credit: Filippo Monteforte/AFP]
Marble pillars and blocks lie where they were abandoned when the city was submerged by a pyroclastic flow from Mount Vesuvius in the 79 AD disaster. But excavators also found a victim of the disaster, the skeleton of a child who had sought shelter there in vain.


The architects "were inspired by Emperor Nero's thermal baths in Rome. The rooms here were to be bigger and lighter, with marble pools," the archaeological site's director Massimo Osanna told AFP.

The Central Baths lie in an area restored under the Great Pompeii Project, launched in 2012 to save the historical site after the collapse of the 2000-year-old "House of the Gladiators", which sparked outrage worldwide.

Magnificent thermal baths in Pompeii unveiled
Excavators found grand mosaic tiles and pillars
[Credit: Rex Features]
"It was an emotionally charged dig," said Alberta Martellone, 43, the archaeologist who led a team of an anthropologist, geologist and vulcanologist in studying the skeleton of the child, who died aged between eight and 10. "He or she was looking for shelter, and found death instead", she said.

The excavation "was also moving from an architectural point of view, because it is unusual to find a building so large, with such ample rooms, in this densely built up city. It transmits a sense of grandiosity," she said.

The construction site with its small skeleton "is a sign of life interrupted, on more than one level," she said.

Magnificent thermal baths in Pompeii unveiled
Archaeologists found the remains of a child in the structure
[Credit: Rex Features]
The city's original public bathhouses were smaller, darker and often overcrowded; the new complex would have provided a more luxurious setting for all those who could afford it -- most citizens, but not slaves.


Recent digs at Pompeii have offered up several impressive finds, including an inscription uncovered last year that proves the city near Naples was destroyed after October 17, 79 AD, and not on August 24 as thought.

Archaeologists in October discovered a vivid fresco depicting an armour-clad gladiator standing victorious as his wounded opponent gushing blood, painted in a tavern believed to have housed the fighters as well as prostitutes.

Magnificent thermal baths in Pompeii unveiled
The bath house never got to be used by Pompeii's ancient inhabitants
[Credit: Rex Features]
Along with the baths, visitors could from Monday visit a small domus sporting a racy fresco depicting the Roman god Jupiter, disguised as a swan, impregnating the Greek mythological figure of Queen Leda.

Across the cobbled Via del Vesuvio, the striking House of the Golden Cupids reopened after work on its mosaic floors.

While treasure hunters regularly pillaged Pompeii down the centuries looking for precious jewels or artifacts, whole areas have yet to be explored by modern-day archaeologists.

Magnificent thermal baths in Pompeii unveiled
A general view shows the House of the Golden Cupids, which reopens after work
on its mosaic floors [Credit: Filippo Monteforte/AFP]
Each discovery helps historians understand not only what life was like in the ancient city, but also what happened in the dramatic final hours, as the skies turned to fire and ash, Osanna said.


The Grand Pompeii Project, which was part funded by the EU, winds up at the end of this year, but the Italian government has earmarked 32 million euros for the digs to continue.

Violent weather events caused by climate change "are our biggest challenge," said Osanna, whose new book Pompeii -- Time Regained describes the race to preserve the vulnerable UNESCO world heritage site.

Magnificent thermal baths in Pompeii unveiled
The recently discovered Leda fresco [Credit: Archaeological Park Pompeii]
"We have 50 people -- restorers, archaeologists, architects, engineers -- on site permanently, who carry out inspections and intervene where necessary, and that number will rise to 70 next year," he added.

The ruined city in southern Italy is the second most visited tourist site in the country, after the Colosseum in Rome, with just under four million visitors in 2019.

Author: Ella Ide | Source: AFP [November 26, 2019]



* This article was originally published here

Astronauts Wrap Up Third Spacewalk for Cosmic Particle Detector Repairs














ISS - Expedition 61 Mission patch / EVA - Extra Vehicular Activities patch.

December 2, 2019

Expedition 61 Commander Luca Parmitano of ESA (European Space Agency) and NASA Flight Engineer Andrew Morgan concluded their spacewalk at 12:33 p.m. EST. During the six hour and two minute spacewalk, the two astronauts successfully installed a new cooling system for the Alpha Magnetic Spectrometer (AMS).

The crew completed the primary task to install the upgraded cooling system, called the upgraded tracker thermal pump system (UTTPS), completed the power and data cable connection for the system, and connected all eight cooling lines from the AMS to the new system. The intricate connection work required making a clean cut for each existing stainless steel tube connected to the AMS then connecting it to the new system through a process of metalworking known as swaging.


Image above: Astronauts Luca Parmitano and Andrew Morgan are pictured during a spacewalk to continue upgrading the station’s cosmic particle detector, the Alpha Magnetic Spectrometer. Image Credit: NASA TV.

The astronauts also completed an additional task to install an insulating blanket on the nadir side of the AMS to replace the heat shield and blanket they removed during the first spacewalk to begin the repair work. The flight control team on Earth initiated power-up of the system and confirmed it is receiving power and data.

It is the first long day of a very busy several weeks for the space station crew, with two cargo resupply spacecraft launching to the station loaded with science investigations; a SpaceX Dragon is scheduled to lift off at 12:51 p.m. Wednesday, and a Russian Progress is set to launch Friday at 4:34 a.m. Crew members then will be focused on the spacecrafts’ arrivals and associated work. Meanwhile, teams on Earth will evaluate the date for the planned fourth spacewalk to conduct leak checks for the spectrometer’s refurbished cooling lines and complete the work to resume operations of the cosmic ray detector.

For more information about the AMS science and spacewalks, listen to the recent podcasts:

- Houston We Have a Podcast Ep 117: Alpha Magnetic Spectrometer: The Science
https://www.nasa.gov/johnson/HWHAP/alpha-magnetic-spectrometer-the-science

- Houston We Have a Podcast Ep 118: Alpha Magnetic Spectrometer: The Spacewalks
https://www.nasa.gov/johnson/HWHAP/alpha-magnetic-spectrometer-the-spacewalks

Parmitano has now conducted five spacewalks in his career for a total of 26 hours and 53 minutes, and Morgan has logged 39 hours and 32 minutes during six spacewalks since his arrival on the station in July. It was the 11th spacewalk at the station this year. Space station crew members have conducted a total of 224 spacewalks in support of assembly and maintenance of the orbiting laboratory. Spacewalkers have now spent a total of 58 days 15 hours and 43 minutes working outside the station.


Image above: Astronauts Luca Parmitano and Andrew Morgan are pictured during a spacewalk to continue upgrading the station’s cosmic particle detector, the Alpha Magnetic Spectrometer. Image Credit: NASA.

Learn more about space station activities by following @space_station and @ISS_Research on Twitter as well as the ISS Facebook and ISS Instagram accounts.

Related links:

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

Alpha Magnetic Spectrometer (AMS): https://www.nasa.gov/mission_pages/station/research/news/ams-spacewalks-attempt-to-revive-scientific-experiment

SpaceX Dragon: https://www.nasa.gov/press-release/nasa-to-broadcast-next-space-station-resupply-launch-prelaunch-activities-4

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

Castlelaw Iron Age Hill Fort and Earth House, Penicuik, Scotland, November 2019.

Castlelaw Iron Age Hill Fort and Earth House, Penicuik, Scotland, November 2019.



* This article was originally published here

18,000-year-old frozen puppy found in Siberia could be ‘oldest confirmed dog’


Researchers are trying to determine whether an 18,000-year-old puppy found in Siberia is a dog or a wolf.

18,000-year-old frozen puppy found in Siberia could be ‘oldest confirmed dog’
Researchers say the animal could be a dog, a wolf or something in between
[Credit: Love Dalen]
The canine - which was two months old when it died - has been remarkably preserved in the permafrost of the Russian region, with its fur, nose and teeth all intact. DNA sequencing has been unable to determine the species.


Scientists say that could mean the specimen represents an evolutionary link between wolves and modern dogs.

18,000-year-old frozen puppy found in Siberia could be ‘oldest confirmed dog’
The puppy was found in eastern Siberia near Yakutsk
[Credit: Love Dalen]
Radiocarbon dating was able to determine the age of the puppy when it died and how long it has been frozen. Genome analyses showed that it was male.

Researcher Dave Stanton at the Centre for Palaeogenetics in Sweden told CNN the DNA sequencing issue meant the animal could come from a population that is a common ancestor of both dogs and wolves.


"We have a lot of data from it already, and with that amount of data, you'd expect to tell if it was one or the other," he said.

Another researcher from the centre, Love Dalen, tweeted a question about whether the specimen is a wolf cub or "possibly the oldest dog ever found".

18,000-year-old frozen puppy found in Siberia could be ‘oldest confirmed dog’
Researchers carefully cleaned the specimen to reveal it was still mostly covered in fur
[Credit: Sergey Fedorov]
Scientists will continue with DNA sequencing and think the findings could reveal a lot about the evolution of dogs.


The puppy has been named "Dogor", which means "friend" in the Yakut language and is also the start of the question "dog or wolf?"

18,000-year-old frozen puppy found in Siberia could be ‘oldest confirmed dog’
Even the whiskers of the puppy were preserved
[Credit: Sergey Fedorov]
Modern dogs are believed to be descendants of wolves, but there is debate over when dogs were domesticated.

A study published in 2017 suggested domestication could have occurred 20,000 to 40,000 years ago.

Source: BBC News Website [November 28, 2019]



* This article was originally published here

Vikram Lander Found













NASA - Lunar Reconnaissance Orbiter (LRO) patch.

Dec. 2, 2019


This image shows the Vikram Lander impact point and associated debris field. Green dots indicate spacecraft debris (confirmed or likely). Blue dots locate disturbed soil, likely where small bits of the spacecraft churned up the regolith. "S" indicates debris identified by Shanmuga Subramanian. This portion of the Narrow Angle Camera mosaic was made from images M1328074531L/R and M1328081572L/R acquired Nov. 11.
Credits: NASA/Goddard/Arizona State University.

The Chandrayaan 2 Vikram lander was targeted for a highland smooth plain about 600 kilometers from the south pole; unfortunately the Indian Space Research Organisation (ISRO) lost contact with their lander shortly before the scheduled touchdown (Sept. 7 in India, Sept. 6 in the United States).  Despite the loss, getting that close to the surface was an amazing achievement. The Lunar Reconnaissance Orbiter Camera team released the first mosaic (acquired Sept. 17) of the site on Sept. 26 and many people have downloaded the mosaic to search for signs of Vikram. Shanmuga Subramanian contacted the LRO project with a positive identification of debris. After receiving this tip, the LROC team confirmed the identification by comparing before and after images. When the images for the first mosaic were acquired the impact point was poorly illuminated and thus not easily identifiable. Two subsequent image sequences were acquired on Oct. 14 and 15, and Nov. 11. The LROC team scoured the surrounding area in these new mosaics and found the impact site (70.8810°S,  22.7840°E, 834 m elevation) and associated debris field. The November mosaic had the best pixel scale (0.7 meter) and lighting conditions (72° incidence angle).

Lunar Reconnaissance Orbiter (LRO). Image Credit: NASA

The debris first located by Shanmuga is about 750 meters northwest of the main crash site and was a single bright pixel identification in that first mosaic (1.3 meter pixels, 84° incidence angle). The November mosaic shows best the impact crater, ray and extensive debris field. The three largest pieces of debris are each about 2x2 pixels and cast a one pixel shadow.


This before and after image ratio highlights changes to the surface; the impact point is near center of the image and stands out due the dark rays and bright outer halo. Note the dark streak and debris about 100 meters to the SSE of the impact point. Diagonal straight lines are uncorrected background artifacts. Image Credits: NASA/Goddard/Arizona State University.


Before and after images show the Vikram impact point. Changes to the surface are subtle and are more easily seen in the ratio image presented above. Animation Credits: NASA/Goddard/Arizona State University.

Related articles & link:

ISRO Just Found Its Lost Vikram Lander on the Moon
https://orbiterchspacenews.blogspot.com/2019/09/isro-just-found-its-lost-vikram-lander.html

Chandrayaan-2 Vikram Moon lander lost signal
https://orbiterchspacenews.blogspot.com/2019/09/chandrayaan-2-vikram-moon-lander-lost.html

Lunar Reconnaissance Orbiter (LRO): http://www.nasa.gov/mission_pages/LRO/main/index.html

Animation (mentioned), Images (mentioned), Text, Credits: NASA/Karl Hille.

Greetings, Orbiter.ch

* This article was originally published here

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