четверг, 4 октября 2018 г.

New simulation sheds light on spiralling supermassive black holes

A new model is bringing scientists a step closer to understanding the kinds of light signals produced when two supermassive black holes, which are millions to billions of times the mass of the Sun, spiral toward a collision. For the first time, a new computer simulation that fully incorporates the physical effects of Einstein’s general theory of relativity shows that gas in such systems will glow predominantly in ultraviolet and X-ray light.

New simulation sheds light on spiraling supermassive black holes
This animation rotates 360 degrees around a frozen version of the simulation in the plane of the disk
[Credit: NASA’s Goddard Space Flight Center]

Just about every galaxy the size of our own Milky Way or larger contains a monster black hole at its center. Observations show galaxy mergers occur frequently in the universe, but so far no one has seen a merger of these giant black holes.

“We know galaxies with central supermassive black holes combine all the time in the universe, yet we only see a small fraction of galaxies with two of them near their centers,” said Scott Noble, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The pairs we do see aren’t emitting strong gravitational-wave signals because they’re too far away from each other. Our goal is to identify — with light alone — even closer pairs from which gravitational-wave signals may be detected in the future.”

Scientists have detected merging stellar-mass black holes — which range from around three to several dozen solar masses — using the National Science Foundation’s Laser Interferometer Gravitational-Wave Observatory (LIGO). Gravitational waves are space-time ripples traveling at the speed of light. They are created when massive orbiting objects like black holes and neutron stars spiral together and merge.

Supermassive mergers will be much more difficult to find than their stellar-mass cousins. One reason ground-based observatories can’t detect gravitational waves from these events is because Earth itself is too noisy, shaking from seismic vibrations and gravitational changes from atmospheric disturbances. The detectors must be in space, like the Laser Interferometer Space Antenna (LISA) led by ESA (the European Space Agency) and planned for launch in the 2030s. Observatories monitoring sets of rapidly spinning, superdense stars called pulsars may detect gravitational waves from monster mergers. Like lighthouses, pulsars emit regularly timed beams of light that flash in and out of view as they rotate. Gravitational waves could cause slight changes in the timing of those flashes, but so far studies haven’t yielded any detections.

But supermassive binaries nearing collision may have one thing stellar-mass binaries lack — a gas-rich environment. Scientists suspect the supernova explosion that creates a stellar black hole also blows away most of the surrounding gas. The black hole consumes what little remains so quickly there isn’t much left to glow when the merger happens.

Gas glows brightly in this computer simulation of supermassive black holes only 40 orbits from merging. 

Models like this may eventually help scientists pinpoint real examples of these powerful binary systems 

[Credit: NASA’s Goddard Space Flight Center]

Supermassive binaries, on the other hand, result from galaxy mergers. Each supersized black hole brings along an entourage of gas and dust clouds, stars and planets. Scientists think a galaxy collision propels much of this material toward the central black holes, which consume it on a time scale similar to that needed for the binary to merge. As the black holes near, magnetic and gravitational forces heat the remaining gas, producing light astronomers should be able to see.

“It’s very important to proceed on two tracks,” said co-author Manuela Campanelli, director of the Center for Computational Relativity and Gravitation at the Rochester Institute of Technology in New York, who initiated this project nine years ago. “Modeling these events requires sophisticated computational tools that include all the physical effects produced by two supermassive black holes orbiting each other at a fraction of the speed of light. Knowing what light signals to expect from these events will help modern observations identify them. Modeling and observations will then feed into each other, helping us better understand what is happening at the hearts of most galaxies.”

The new simulation shows three orbits of a pair of supermassive black holes only 40 orbits from merging. The models reveal the light emitted at this stage of the process may be dominated by UV light with some high-energy X-rays, similar to what’s seen in any galaxy with a well-fed supermassive black hole.

Three regions of light-emitting gas glow as the black holes merge, all connected by streams of hot gas: a large ring encircling the entire system, called the circumbinary disk, and two smaller ones around each black hole, called mini disks. All these objects emit predominantly UV light. When gas flows into a mini disk at a high rate, the disk’s UV light interacts with each black hole’s corona, a region of high-energy subatomic particles above and below the disk. This interaction produces X-rays. When the accretion rate is lower, UV light dims relative to the X-rays.

Based on the simulation, the researchers expect X-rays emitted by a near-merger will be brighter and more variable than X-rays seen from single supermassive black holes. The pace of the changes links to both the orbital speed of gas located at the inner edge of the circumbinary disk as well as that of the merging black holes.

This 360-degree video places the viewer in the middle of two circling supermassive black holes around 18.6 million miles 

(30 million kilometers) apart with an orbital period of 46 minutes. The simulation shows how the black holes distort 

the starry background and capture light, producing black hole silhouettes. A distinctive feature called a photon

 ring outlines the black holes. The entire system would have around 1 million times the Sun’s mass 

[Credit: NASA’s Goddard Space Flight Center; background, ESA/Gaia/DPAC]

“The way both black holes deflect light gives rise to complex lensing effects, as seen in the movie when one black hole passes in front of the other,” said Stéphane d’Ascoli, a doctoral student at École Normale Supérieure in Paris and lead author of the paper. “Some exotic features came as a surprise, such as the eyebrow-shaped shadows one black hole occasionally creates near the horizon of the other.”

The simulation ran on the National Center for Supercomputing Applications’ Blue Waters supercomputer at the University of Illinois at Urbana-Champaign. Modeling three orbits of the system took 46 days on 9,600 computing cores. Campanelli said the collaboration was recently awarded additional time on Blue Waters to continue developing their models.

The original simulation estimated gas temperatures. The team plans to refine their code to model how changing parameters of the system, like temperature, distance, total mass and accretion rate, will affect the emitted light. They’re interested in seeing what happens to gas traveling between the two black holes as well as modeling longer time spans.

“We need to find signals in the light from supermassive black hole binaries distinctive enough that astronomers can find these rare systems among the throng of bright single supermassive black holes,” said co-author Julian Krolik, an astrophysicist at Johns Hopkins University in Baltimore. “If we can do that, we might be able to discover merging supermassive black holes before they’re seen by a space-based gravitational-wave observatory.”

A paper describing the team’s analysis of the new simulation was published in the Astrophysical Journal.

Author: Jeanette Kazmierczak | Source: NASA/Goddard Space Flight Center [October 02, 2018]



Mexico’s Yucatan Peninsula holds still-undiscovered archaeological treasures

People who live on the Yucatan Peninsula, which includes the Mexican states of Yucatan, Quintana Roo and Campeche, consider the ground of the region so flat that under any mound or hill there must hold archaeological treasures, and in many cases that is true.

Mexico's Yucatan Peninsula holds still-undiscovered archaeological treasures
People who live on the Yucatan Peninsula, like this local seen on Sept. 24, 2018, consider the ground of the region
so flat that under any mound or hill there must hold archaeological treasures, and in many cases that is true
[Credit: EFE-EPA/Alonso Cupul]

The rural community of Dos Aguadas in the Jose Maria Morelos municipality, in the Mayan region of Quintana Roo, is a perfect example. Many of its inhabitants are accustomed not only to guarding their lands but also to protecting whatever ruins may lie buried there.

Dos Aguadas is close to Punto Put, which is where the states of Campeche, Quintana Roo and Yucatan border one another geographically; together with Belize and Guatemala they form the Yucatan Peninsula.

One of the main attractions of the Dos Aguadas pyramids is that they are connected by a network of underground tunnels, residents said.

Besides the pyramids that have been partially explored, the inhabitants of the village themselves admit that other ruins once existed in the community, but at the time no one knew what they were and so the locals used them to build walls around a school and around people’s homes.

Mexico's Yucatan Peninsula holds still-undiscovered archaeological treasures
People who live on the Yucatan Peninsula, like this local seen on Sept. 24, 2018, consider the ground of the region
so flat that under any mound or hill there must hold archaeological treasures, and in many cases that is true
[Credit: EFE-EPA/Alonso Cupul]

In Quintana Roo, according to National Anthropology and History Institute (INAH) figures, more than 2,200 archaeological ruins have been entered in the national catalog of archaeological sites and are open to the public.

Besides the large Mayan cities of Tulum, Coba and Kohunlich, all in Quintana Roo, various archaeological digs have shown the presence of Maya settlers across the entire area they used for growing crops.

The 13 archaeological areas open to the public in Quintana Roo for an authorized entrance fee were visited between January and August of this year by more than 44,300 national and foreign tourists.

These areas are El Rey and San Miguelito in Cancun, El Meco on Isla Mujeres, Xcaret and Xel Ha on the Riviera Maya, San Gervasio in Cozumel, Tulum and Coba in the Tulum municipality, Muyil in Felipe Carrillo Puerto, Chacchoben in Bacalar and Kohunlich, along with Dzibanche and Kinichna, and Oxtankah in the Othon P. Blanco municipality.

Author: Lourdes Cruz | Source: EFE [October 02, 2018]



Prehistoric art hints at lost Indian civilisation

The discovery of rock carvings believed to be tens of thousands of years old in India’s western state of Maharashtra has greatly excited archaeologists who believe they hold clues to a previously unknown civilisation, BBC Marathi’s Mayuresh Konnur reports.

Prehistoric art hints at lost Indian civilisation


The rock carvings – known as petroglyphs – have been discovered in their thousands atop hillocks in the Konkan region of western Maharashtra.

Mostly discovered in the Ratnagiri and Rajapur areas, a majority of the images etched on the rocky, flat hilltops remained unnoticed for thousands of years.

Prehistoric art hints at lost Indian civilisation


Most of them were hidden beneath layers of soil and mud. But a few were in the open – these were considered holy and worshipped by locals in some areas.
The sheer variety of the rock carvings have stunned experts – animals, birds, human figures and geometrical designs are all depicted.

Prehistoric art hints at lost Indian civilisation


The way the petroglyphs have been drawn, and their similarity to those found in other parts of the world, have led experts to believe that they were created in prehistoric times and are possibly among the oldest ever discovered.

“Our first deduction from examining these petroglyphs is that they were created around 10,000BC,” the director of the Maharashtra state archaeology department, Tejas Garge, told the BBC.

Prehistoric art hints at lost Indian civilisation


The credit for their discovery goes to a group of explorers led by Sudhir Risbood and Manoj Marathe, who began searching for the images in earnest after observing a few in the area. Many were found in village temples and played a part in local folklore.
“We walked thousands of kilometres. People started sending photographs to us and we even enlisted schools in our efforts to find them. We made students ask their grandparents and other village elders if they knew about any other engravings. This provided us with a lot of valuable information,” Mr Risbood told the BBC.

Prehistoric art hints at lost Indian civilisation


Together they found petroglyphs in and around 52 villages in the area. But only around five villages were aware that the images even existed.

Apart from actively searching for them, Mr Risbood and Mr Marathe have also played an important role in documenting the petroglyphs and lobbying authorities to get involved in studying and preserving them.

Prehistoric art hints at lost Indian civilisation


Mr Garge says the images appear to have been created by a hunter-gatherer community which was not familiar with agriculture.

“We have not found any pictures of farming activities. But the images depict hunted animals and there’s detailing of animal forms. So this man knew about animals and sea creatures. That indicates he was dependent on hunting for food.”

Dr Shrikant Pradhan, a researcher and art historian at Pune’s Deccan College who has studied the petroglyphs closely, said that the art was clearly inspired by things observed by people at the time.

“Most of the petroglyphs show familiar animals. There are images of sharks and whales as well as amphibians like turtles,” Mr Garge adds.

But this begs the question of why some of the petroglyphs depict animals like hippos and rhinoceroses which aren’t found in this part of India. Did the people who created them migrate to India from Africa? Or were these animals once found in India?

The state government has set aside a fund of 240 million rupees ($3.2m; £2.5m) to further study 400 of the identified petroglyphs.

It is hoped that some of these questions will eventually be answered.

Source: BBC News Website [October 02, 2018]



Mysterious female pottery face from east China sends 7,300 year-old smile

A mysterious piece of pottery shaped as a female head sends a smile from 7,300 years ago, as its host museum in east China’s Anhui Province starts a global naming bid for the ancient relic.

Mysterious female pottery face from east China sends 7,300 year-old smile
Pottery shaped as a female head unearthed from a Neolithic site at Shuangdun village in
east China’s Anhui Province [Credit: Xinhua/Anhui Bengbu Museum]

Ji Yong, curator of the Anhui Bengbu Museum in the city of Bengbu, said the statue was among 600 pieces of pottery unearthed from a New Stone Age site at Shuangdun village in Anhui in 1985.

Using Carbon 14 technology, the relics were dated back to 7,300 years ago.

However, it is still unknown what the statue was used for and why it was the only one of its kind, with the rest being utensils bearing inscriptions of various symbols believed to be origins of Chinese characters.

The statue, made with earth containing mica powder and quartz, is a flickering tattooed female face with marks emblazoned on her forehead that archaeologists have judged as a sun symbol.

Mysterious female pottery face from east China sends 7,300 year-old smile
Pottery shaped as a female head unearthed from a Neolithic site at Shuangdun village in
east China’s Anhui Province 
[Credit: Xinhua/Zhang Duan]

Measuring 6.5 cm in height and width, the relic is the earliest example of such pottery ever found in China.

Zhang Dong, professor with the Chinese Academy of Social Sciences, said international archaeological experts tended to link the inscriptions on the pottery items from Shuangdun to drawings in the Olmec civilization and hieroglyphic inscriptions in Mayan culture.

Ji said that following the global naming bid, the museum would hold an international symposium on the the item.

“I think it is the earliest and the most beautiful facial portrait, and suggests the humans had developed from emotional thinking to rational thinking,” said Xu Xiaohong, a member of China Sculpture Society.

Mysterious female pottery face from east China sends 7,300 year-old smile
Pottery shaped as a female head unearthed from a Neolithic site at Shuangdun village in
east China’s Anhui Province [Credit: Xinhua/Anhui Bengbu Museum]

He suggested naming the statue “The Goddess of the Huaihe River,” since the ruins were found on the bank of the Huaihe, which is located in the midway of China’s two largest rivers, the Yangtze and Yellow rivers.

Shuangdun culture appears in the same period as the late Neolithic group known as the Yangshao, which originated from the middle reaches of the Yellow River, and Majiabang culture where archaeologists excavated 6,000-year-old rice grains in the lower reaches of the Yangtze in present-day Shanghai.

In the museum, the statue’s caption says “pottery human head portrait with facial tattoos.”

Wang Jihuai, a researcher with the academy, said although a consensus had not been reached, those involved with Shuangdun archeological research tend to believe that the civilization was a matriarchy with a sorceress dominating the community.

Mysterious female pottery face from east China sends 7,300 year-old smile
The Neolithic site at Shuangdun village in Bengbu, east China’s Anhui Province
[Credit: Xinhua/Anhui Bengbu Museum]

 “The portrait might be the image of a sorceress,” Wang said.

There are four-handled kettles and cooking devices unearthed in ruins, where massive animal bones were also discovered.

“The discovery of Shuangdun culture suggests that the Huaihe River Basin was one of the origins of Chinese civilization and Chinese characters,” Wang said.

Since the museum launched the bid to name the smiling portrait through media outlets and Chinese social media in September, it has received considerable feedback.

Mysterious female pottery face from east China sends 7,300 year-old smile
The Neolithic site at Shuangdun village in Bengbu, east China’s Anhui Province
[Credit: Xinhua/Anhui Bengbu Museum]

“The portrait just has a head, and the decoration on the forehead suggests she was someone high ranking. Maybe we should name her Big Cheese,” said Muhammad Firdaus Samijadi from Surinam.
Enzo Hilbert from France said the portrait was certainly a female figure. “She must have been a flamen. I’d like to name her Watermelon Girl or Druidess,” he said.

Xun Yiran, a Bengbu local, said that since the portrait embodied the ancient culture of the Huaihe River, the name should carry its origin. “I suggest to name her the Mother of the Huaihe River,” he said.

Source: Xinhua [October 03, 2018]



Neanderthal healthcare practices crucial to survival

New research has suggested that Neanderthals embraced healthcare practices, such as assisting in cases of serious injury and the challenges of childbirth.

Neanderthal healthcare practices crucial to survival
Skeletal remains display several episodes of injury and recovery
[Credit: University of York]

Healthcare practices in this period of human evolution have often been studied alongside complex cultural behaviour, mostly based around research into rituals and symbols associated with death. This new study, however, sets out, for the first time, that healthcare could have had a more strategic role in Neanderthal survival.

Previous research at the University had already suggested that compassion and caring for the injured and dying could have been a factor in the development of healthcare practices, but further investigation has now shown that there was evolutionary drivers behind it too.

Researchers investigated the skeletal remains of more than 30 individuals where minor and serious injuries were evident, but did not lead to loss of life. The samples displayed several episodes of injury and recovery, suggesting that Neanderthals must have had a well-developed system of care in order to survive.

Animal attacks

Dr. Penny Spikins, from the University of York’s Department of Archaeology, said: “Neanderthals faced multiple threats to their lives, particularly from large and dangerous animals, but in popular culture Neanderthals have such a brutish and strong image that we haven’t really thought too deeply about their vulnerabilities before now.

“We have evidence of healthcare dating back 1.6 million years ago, but we think it probably goes further back than this. We wanted to investigate whether healthcare in Neanderthals was more than a cultural practice; was it something they just did or was it more fundamental to their strategies for survival?

“The high level of injury and recovery from serious conditions, such as a broken leg, suggests that others must have collaborated in their care and helped not only to ease pain, but to fight for their survival in such a way that they could regain health and actively participate in the group again.”

Serious risk

It is generally accepted that more than 80% of the skeletal remains known to archaeologists display several injuries, some of which may have required simple remedies, such as food and rest, and others that would have required serious levels of care due to a high risk to life.

Neanderthals lived in small groups, so any one loss of life was particularly significant to the survival of the whole community. Injury, over disease, was the most common threat, as Neanderthals didn’t live in the type of environment, or in large enough communities, to be at high risk from pathogens.

Neanderthal women, however, were at risk from difficulties in childbirth. The shape of their pelvis and the size and shape of a child’s head was similar to that of modern-day humans, so it is assumed that they would also have encountered some common issues in childbirth.

Neanderthal ‘midwives’

Dr. Spikins said: “It is likely that they would have had assisted childbirth; the role that we now attribute to midwives. Without support, they probably could not have survived the toll that the death rate of mothers and babies could have taken on their communities.

“When we look at the daily risks and dangers involved in hunting and finding food, as well as in childbirth in respect to their small hunting communities, it is not surprising that they would develop practices to improve health and reduce mortality risk.

“We can start to see healthcare as a pattern of evolutionary significant collaborative behaviour, alongside hunting together, food sharing and parenting. In this we can see why providing healthcare to those in need today is such an important part of human life.”

Researchers now aim to expand this work to look at potential methods of healthcare and how far back healthcare practices can be traced.

Author: Samantha Martin | Source: University of York [October 03, 2018]



Scientists ‘virtually unravel’ burnt 16th century scroll

Scientists are on the look-out for damaged and unreadable ancient scrolls as brand new techniques have revealed the hidden text inside a severely burnt 16th century sample.

Scientists ‘virtually unravel’ burnt 16th century scroll
Credit: Cardiff University

The new development, the latest in a long line of advancements in the field in recent years, has shown how ‘virtual unravelling’ can be achieved using a more autonomous approach and with scrolls that contain multiple pages.

Similarly, the new computer techniques can now handle very large data sets and deal with more complex shapes and sizes.

This has been demonstrated by virtually unravelling a 16th century scroll from Diss Heywood Manor in Norwich, which was left severely charred, damaged and fused together with no possible way of physically opening the scroll without destroying it.

The scroll, which was 270mm wide, would have contained information on life in the manor and included details on land transactions, disturbances of the peace, payment of fines, names of jurors and information on the upkeep of land.

Researchers at Cardiff University have been refining their technique since they first revealed the hidden text of a scroll from Bressingham Manor over five years ago.

Their technique, which involves collaborators from the UK and across the world, firstly involves using x-ray tomography, usually reserved for use in the medical field, to create thousands of thin cross sections of the scroll. In each cross-section, ink from the scroll is made visible as bright blobs.

Using highly advanced computer algorithms, the team are then able to piece together each of the cross sections and their associated ink marks to form a flat representation of the scroll.

The text obtained from the Diss Heywood scroll confirmed that it does indeed relate to Heywood Hall and that it is a record of the Curia Generalis, the General Court, which usually refers to the Court Leet where peace keeping functions were exercised.

The results also confirmed that the scroll deals with land transactions and possibly testamentary business. It was also possible to pick out names of individuals.

Principal investigator on the project Professor Paul Rosin, from Cardiff University’s School of Computer Science and Informatics, said: “The scroll from Diss Heyword was an extremely challenging sample to work with, not least because it contained four sheets of parchment and many touching layers, which can result in text being assigned to the wrong sheets.

“In addition to this, the scroll was heavily discoloured and creased and was covered in soot-like deposits over the entire exterior. Nevertheless, we’ve shown that even with the most challenging of samples, we can successfully draw information from it.

“We know that there is a large body of historical documents in museums and archives that are too fragile to be opened or unrolled, so we would certainly welcome the opportunity to try out our new techniques.

“Similarly, the method we’ve developed is heavily automated, opening up the possibility of exploring a larger range of documents and even other types of media, such as old and damaged camera films.”

Source: Cardiff University [October 03, 2018]



Yant Flat Cliffs | #Geology #GeologyPage #USA Location: Utah,…

Yant Flat Cliffs | #Geology #GeologyPage #USA

Location: Utah, USA

Yant Flat Cliffs, a stretch of red and orange rocks right at the upper edge of the sandstone layer, extending about three miles along the southern boundary of a rocky plateau (Yant Flat). Above here the mountain slopes are wooded and overgrown, but the cliffs and their associated buttes and ravines are mostly unvegetated, and richly colored

The wavy bands occur in shades of orange, red, yellow and pink, and white, which when combined with varied rock forms and textures make for a very photogenic landscape.

Geology Page



Aquamarine | #Geology #GeologyPage #Mineral Locality: Ameib…

Aquamarine | #Geology #GeologyPage #Mineral

Locality: Ameib Farm, Usakos, Erongo, Namibia

Size: 14.6 x 7.4 x 9.5 cm

Photo Copyright © Anton Watzl Minerals

Geology Page



Calcite | #Geology #GeologyPage #Mineral Locality: Egremont,…

Calcite | #Geology #GeologyPage #Mineral

Locality: Egremont, Cumberland, England

Size: 8 x 6 x 5.9 cm

Photo Copyright © Anton Watzl Minerals

Geology Page



Pyritized Ammonite | #Geology #GeologyPage #Ammonite…

Pyritized Ammonite | #Geology #GeologyPage #Ammonite #Fossil

Locality: Volga River Area, Saratov Region, Russia

Photo Copyright © Astrogallery

Geology Page



Anglesite | #Geology #GeologyPage #Mineral Locality: Touissit,…

Anglesite | #Geology #GeologyPage #Mineral

Locality: Touissit, Oujda-Angad Prov., Oriental Region, Morocco

Size: 8 x 5.5 x 3.5 cm

Photo Copyright © Anton Watzl Minerals

Geology Page



Fluorite and Barite | #Geology #GeologyPage #Mineral Locality:…

Fluorite and Barite | #Geology #GeologyPage #Mineral

Locality: Berbes Mining area, Ribadesella, Asturias, Spain

Size: 14.4 x 10.5 x 6.2

Photo Copyright © Saphira Minerals

Geology Page



Expedition 56 Trio Undocks from ISS and landed safely on Earth

ROSCOSMOS – Soyuz MS-08 Mission patch.

October 4, 2018

Expedition 56 Commander Drew Feustel and Flight Engineer Ricky Arnold of NASA, along with Flight Engineer and Soyuz Commander Oleg Artemyev of the Russian space agency Roscosmos undocked from the International Space Station at 3:57 a.m. EDT to begin their trip home.

Image above: The Soyuz MS-08 spacecraft that is returning three Expedition 56 crew members back to Earth is pictured from a space station camera just before to undocking from the Poisk module. Image Credit: NASA TV.

Deorbit burn is scheduled for approximately 6:51 a.m., with landing in Kazakhstan targeted for 7:45 a.m. (5:45 p.m. Kazakhstan time).

Soyuz MS-08 undocking and departure

At the time of undocking, Expedition 57 will begin formally aboard the station, with Commander Alexander Gerst of ESA (European Space Agency), NASA’s Serena Aunon-Chancellor and Roscosmos cosmonaut Sergey Prokopyev comprising a three-person crew for one week.

Station Crew Back on Earth After 197 Days in Space

Three crew members who have been living and working aboard the International Space Station have landed safely in Kazakhstan.

Expedition 56 Commander Drew Feustel and Flight Engineer Ricky Arnold of NASA, along with Flight Engineer and Soyuz Commander Oleg Artemyev of the Russian space agency Roscosmos landed at 7:44 a.m. EDT (5:44 p.m. in Kazakhstan) southeast of the remote town of Dzhezkazgan in Kazakhstan.

Image above: The Soyuz MS-08 spacecraft that is carrying Expedition 55/56 crew members Ricky Arnold, Drew Feustel and Oleg Artemyev is pictured seconds away from landing under a parachute in Kazakhstan. Image Credit: NASA TV.

The crew completed hundreds of experiments during its 197-day expedition. Highlights included an investigation to study ultra-cold quantum gases using the first commercial European facility for microgravity research, and a system that uses surface forces to accomplish liquid-liquid separation.

The crew also welcomed five cargo spacecraft that delivered several tons of supplies and research experiments. The 14th SpaceX Dragon arrived in April, shortly after the three crew members did, bringing supplies and equipment, and the 15th Dragon arrived in July. The ninth Northrop Grumman Cygnus resupply spacecraft arrived in May before the end of Expedition 55. A Russian Progress completed a record rapid rendezvous of less than four hours in August. And, the seventh Japanese Konotouri cargo craft arrived just a week before the Expedition 56 trio departed for home.

Both Feustel and Arnold participated in dozens of educational events while in space as part of NASA’s Year of Education on Station, reaching more than 200,000 students in 29 states. Feustel now has logged more than 226 days in space on three spaceflights, and Arnold more than 209 days on two missions.

Soyuz MS-08 landing

The duo ventured outside the space station on three spacewalks to effect maintenance and upgrades during Expeditions 55 and 56. Their work included replacing and upgrading external cameras, including those that will facilitate the approach and docking of the Boeing Starliner and SpaceX Crew Dragon commercial crew spacecraft when they begin launching soon from American soil. The spacewalkers also replaced components of the space station’s cooling system and communications network, and installed new wireless communication antennas for external experiments. Feustel has accumulated 61 hours and 48 minutes over nine career spacewalks, and ranks third overall among American astronauts. Arnold has 32 hours and 4 minutes over five career spacewalks.

Artemyev conducted one spacewalk with fellow cosmonaut Sergey Prokopyev to manually launch four small technology satellites and install an experiment called Icarus onto the Russian segment of the space station. The spacewalk timed out at 7 hours and 46 minutes, the longest in Russian space program history. Artemyev now has spent 366 days in space on his two flights.

Expedition 57 continues station research and operations with a crew comprised of Serena Auñón-Chancellor of NASA, Alexander Gerst of ESA (European Space Agency) and Sergey Prokopyev of Roscosmos. Gerst assumed command of the station as Feustel prepared to depart.

NASA astronaut Nick Hague and Roscosmos cosmonaut Alexey Ovchinin are scheduled to launch Oct. 11 for a same-day arrival, increasing the crew size to five.

Related article:

Dragon delivers some ICE:

Related links:

Expedition 57: https://www.nasa.gov/mission_pages/station/expeditions/expedition56/index.html

NASA’s Year of Education on Station: https://www.nasa.gov/audience/foreducators/stem-on-station/year-of-education.html

Icarus: https://directory.eoportal.org/web/eoportal/satellite-missions/i/iss-icarus

Ultra-cold quantum gases: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=7396

Commercial European facility: http://www.esa.int/Our_Activities/Human_Spaceflight/Research/Ice_Cubes_cool_new_commercial_opportunity_on_the_International_Space_Station

Liquid-liquid separation: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7696

Commercial crew: http://www.nasa.gov/commercialcrew

Spacewalks: https://www.nasa.gov/mission_pages/station/spacewalks

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), Videos, Text, Credits: NASA/Mark Garcia/NASA TV/SciNews.

Best regards, Orbiter.chArchive link

Green smoothies in space

ISS – International Space Station logo.

4 October 2018

The Artemiss experiment that ran on the International Space Station has shown that ESA can cultivate oxygen from plants in space. It is paving the way for more demonstrations of regenerative life-support technology, and astronauts get a green smoothie to boot.

Microalgae batch

Check, check, and check

Microalgae Arthrospira, commonly known as spirulina were launched to the Space Station in December 2017 where they recycled carbon dioxide into oxygen to produce edible proteins.

A liquid sample of spirulina was loaded into a photobioreactor, a cylinder bathed in light. Over the course of a month the microorganism converted the light into energy, producing oxygen as a by-product at the same speed as it would on Earth. Researchers now confirm that the biological process on Earth works the same in space.

Unloading a batch

Four photobioreactors ran in parallel while the oxygen and biomass produced by the spirulina was recorded. Extracting oxygen from the liquid posed a challenge, as liquids and gases do not naturally separate in weightlessness, but the novel bioreactor technology behind Artemiss performed well with accurate measurements.

The beauty of the Arthrospira microorganism is that it is edible if pure. Thanks to highly accurate computer models and subsequent experiment design, all the samples returned pure. The green smoothie-like product was safe to add to astronaut diets as a source of protein.

Round two

On its first round on the Space Station, researchers tested a batch of the microalgae, the next step is to run the experiment with a continuous supply of spirulina for three months.

The project is part of the Micro-Ecological Life Support System Alternative – Melissa –programme that is developing regenerative technologies for life support.

Employing a closed-loop concept, Melissa aims to recover food, water, and oxygen from organic waste such as carbon dioxide and minerals.

The programme covers many research, education, and technological activities such as the AstroPlant citizen science project that is collecting data on how plants grow in different environments.

The 5 compartments of the MELiSSA loop

Using a different approach, ESA’s Advanced Close Loop System arrived at the International Space Station last week and promises to recycle carbon dioxide into water.

Soon to join this Artemiss experiment is another technology precursor called Urinis that will look into recycling urine to provide nitrogen gas, plant nutrients, and water on the Space Station.

A decade of European science in space

In the meantime, future astronauts can count on getting their green smoothie in space too.

Related links:

AstroPlant: http://www.esa.int/Our_Activities/Human_Spaceflight/AstroPlant_citizen_science_for_growing_plants_in_space

ESA’s Advanced Close Loop System arrived at the International Space Station: http://www.esa.int/Our_Activities/Human_Spaceflight/International_Space_Station/Next-generation_life-support_system_heading_to_Space_Station

European space laboratory Columbus: http://www.esa.int/Our_Activities/Human_Spaceflight/Columbus

Experiment archive: http://eea.spaceflight.esa.int/

International Space Station Benefits for Humanity: http://www.esa.int/Our_Activities/Human_Spaceflight/International_Space_Station_Benefits_for_Humanity

Images, Text, Credits: ESA/NASA.

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Cimmerians, Scythians and Sarmatians came from…

Apparently they all came from the eastern Pontic-Caspian steppe. There’s a new paper about that at Science Advances (see here). Below is the abstract, emphasis is mine:

For millennia, the Pontic-Caspian steppe was a connector between the Eurasian steppe and Europe. In this scene, multidirectional and sequential movements of different populations may have occurred, including those of the Eurasian steppe nomads. We sequenced 35 genomes (low to medium coverage) of Bronze Age individuals (Srubnaya-Alakulskaya) and Iron Age nomads (Cimmerians, Scythians, and Sarmatians) that represent four distinct cultural entities corresponding to the chronological sequence of cultural complexes in the region. Our results suggest that, despite genetic links among these peoples, no group can be considered a direct ancestor of the subsequent group. The nomadic populations were heterogeneous and carried genetic affinities with populations from several other regions including the Far East and the southern Urals. We found evidence of a stable shared genetic signature, making the eastern Pontic-Caspian steppe a likely source of western nomadic groups.

Krzewinska et al., Ancient genomes suggest the eastern Pontic-Caspian steppe as the source of western Iron Age nomads, Science Advances, 03 Oct 2018: Vol. 4, no. 10, eaat4457, DOI: 10.1126/sciadv.aat4457
See also…
Late PIE ground zero now obvious; location of PIE homeland still uncertain, but…


Landslides in JapanOn Sept. 6, 2018, shortly after the remnants…

Landslides in Japan

On Sept. 6, 2018, shortly after the remnants of Typhoon Jebi drenched southern Hokkaido, a powerful earthquake rattled the Japanese island. The 6.6-magnitude quake shook the surface enough to unleash hundreds of landslides.

The Landsat 8 satellite acquired imagery of the widespread damage. An image acquired on Sept. 15, 2018, shows mud and debris in a hilly area east of Abira. For comparison, the previous image shows the same area on July 26, 2017.

Read more about this

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2018 October 4 Opportunity After the Storm Image Credit:…

2018 October 4

Opportunity After the Storm
Image Credit: HiRISE, MRO, LPL (U. Arizona), NASA

Explanation: On Mars dust storms can’t actually blow spacecraft over, but they can blot out the Sun. Over three months ago a planet-wide dust storm caused a severe lack of sunlight for the Mars rover Opportunity at its location near the west rim of Endeavor crater. The lack of sunlight sent the solar-powered Opportunity into hibernation and for over 115 sols controllers have not received any communication from the rover. The dust is clearing as the storm subsides though. On September 20th, when this image was taken by the Mars Reconnaissance Orbiter’s HiRISE camera, about 25 percent of the sunlight was reaching the surface again. The white box marks a 47-meter-wide (154-foot-wide) area centered on a blip identified as the silent-for-now Opportunity rover.

∞ Source: apod.nasa.gov/apod/ap181004.html

Hubble finds compelling evidence for a moon outside the Solar System

ESA – Hubble Space Telescope logo.

3 October 2018

Neptune-sized moon orbits Jupiter-sized planet

Exomoon orbiting its planet (artist’s impression)

Using the NASA/ESA Hubble Space Telescope and older data from the Kepler Space Telescope two astronomers have found the first compelling evidence for a moon outside our own Solar System. The data indicate an exomoon the size of Neptune, in a stellar system 8000 light-years from Earth. The new results are presented in the journal Science Advances.

The hunt for exoplanets — planets outside our own Solar System — provided its first results only 30 years ago. While astronomers now find these planets on a regular basis, the search for moons orbiting exoplanets wasn’t successful — until today.

In 2017 NASA’s Kepler Space Telescope detected hints of an exomoon orbiting the planet Kepler-1625b. Now, two scientists from Columbia University in New York (USA) have used the incomparable capabilities of the NASA/ESA Hubble Space Telescope to study the star Kepler-1625, 8000 light-years away, and its planet in more detail. The new observations made with Hubble show compelling evidence for a large exomoon orbiting the only known planet of Kepler-1625. If confirmed, this would be the first discovery of a moon outside our Solar System.

The candidate moon, with the designation Kepler-1625b-i, is unusual because of its large size; it is comparable in diameter to the planet Neptune. Such gargantuan moons are unknown in our own Solar System. “This may yield new insights into the development of planetary systems and may cause astronomers to revisit theories of how moons form,” Alex Teachey, a graduate student who led the study, explained excitedly [1].

Hubble Space Telescope (HST)

Like its moon, Kepler-1625b is also bigger than its counterparts in the Solar System. The exoplanet is a gas giant, several times more massive than Jupiter [2]. It orbits its parent star at a distance similar to the distance between the Sun and Earth, which puts it — and its candidate moon — at the inner edge of the habitable zone of the star system [3].

To find evidence for the existence of the exomoon, the team observed the planet while it was in transit in front of its parent star, causing a dimming of the starlight. “We saw little deviations and wobbles in the light curve that caught our attention,” David Kipping, second author of the study, said.

The planet was observed by Hubble before and during its 19-hour-long transit. After the transit ended, Hubble detected a second and much smaller decrease in the star’s brightness approximately 3.5 hours later, consistent with the effect of a moon trailing the planet. “It was definitely a shocking moment to see that light curve — my heart started beating a little faster and I just kept looking at that signature,” David Kipping described his feelings. Unfortunately, the scheduled Hubble observations ended before the complete transit of the moon could be captured.

Transit of exoplanet and exomoon

In addition to this second dip in the light curve, Hubble provided compelling supporting evidence for the moon hypothesis by detecting the planet’s transit more than an hour earlier than predicted. This is consistent with a model of the system in which the planet and its moon orbit a common centre of gravity, causing the planet to wobble away from its predicted location [4].

In principle this anomaly could also be caused by the gravitational pull of a hypothetical second planet in the system, but the Kepler Space Telescope found no evidence for additional planets around the star during its four year mission. Still, further observations by Hubble are needed to fully confirm the existence of Kepler-1625b-i.

“If confirmed, Kepler-1625b-i will certainly provide an interesting puzzle for theorists to solve,” said Kipping. Teachey concluded: “It is an exciting reminder of how little we really know about distant planetary systems and the great spirit of discovery exoplanetary science embodies.”


[1] The moons of Jupiter and Saturn likely formed through the agglomeration into a disc of material orbiting the planets, so it is possible that this exomoon also formed in a circumplanetary disc. Another possibility is that a passing object was captured by the planet’s gravity. Tidal forces between the two objects would rob momentum from the less massive companion and eventually pull it into a permanent orbit. There are no indications of tidal capture among our Solar System’s moons. In the case of the Earth–Moon system, an early collision with a larger body is hypothesised to have blasted off material that later coalesced into a moon. However, Kepler-1625b and its candidate moon are gaseous, not rocky, so such a collision would not have led to the condensation of a satellite.

[2] Despite its size, the mass of the candidate moon is estimated to be only 1.5 percent of the mass of its companion planet. This value is close to the mass ratio between Earth and the Moon.

[3] While both the planet and its candidate moon are within the habitable zone, where moderate temperatures allow for the existence of liquid water, both bodies are considered to be gaseous and therefore unsuitable for life as we know it.

[4] A distant observer watching the Earth and Moon transit the Sun would note similar anomalies in the timing of Earth’s transit.

More information:

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

The results were presented in the paper Evidence for a large exomoon orbiting Kepler-1625b in the journal Science Advances.

The team of astronomers in this study consists of Alex Teachey and David M. Kipping (Columbia University, New York, USA).


Images of Hubble: http://www.spacetelescope.org/images/archive/category/spacecraft/

Hubblesite release: http://hubblesite.org/news_release/news/2018-45

Science paper: http://www.spacetelescope.org/static/archives/releases/science_papers/heic1817/heic1817a.pdf

NASA’s Kepler Space Telescope: https://www.nasa.gov/mission_pages/kepler/main/index.html

NASA/ESA Hubble Space Telescope (HST): https://www.spacetelescope.org/

Image, Animation, Text, Credits: NASA, ESA/Video Credits: Credit: ESA/Hubble, L. Calçada.

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New tool helps scientists better target the search for alien life

Could there be another planet out there with a society at the same stage of technological advancement as ours? To help find out, EPFL scientist Claudio Grimaldi, working in association with the University of California, Berkeley, has developed a statistical model that gives researchers a new tool in the search for the kind of signals that an extraterrestrial society might emit. His method — described in an article appearing in Proceedings of the National Academy of Sciences — could also make the search cheaper and more efficient.

New tool helps scientists better target the search for alien life
Schematic view of the Milky Way showing six isotropic extraterrestrial emission processes forming spherical shells filled
 by radio signals. The outer radii of the spherical shells are proportional to the time at which the signals were first
emitted, while the thicknesses are proportional to the duration of the emissions. In this example, the Earth
is illuminated by one of these signals [Credit: Claudio Grimaldi/EPFL]

Atrophysics initially wasn’t Grimaldi’s thing; he was interested more in the physics of condensed matter. Working at EPFL’s Laboratory of Physics of Complex Matter, his research involved calculating the probabilities of carbon nanotubes exchanging electrons. But then he wondered: if the nanotubes were stars and the electrons were signals generated by extraterrestrial societies, could we calculate the probability of detecting those signals more accurately?
This is not pie-in-the-sky research — scientists have been studying this possibility for nearly 60 years. Several research projects concerning the search for extraterrestrial intelligence (SETI) have been launched since the late 1950s, mainly in the United States. The idea is that an advanced civilization on another planet could be generating electromagnetic signals, and scientists on Earth might be able to pick up those signals using the latest high-performance radio telescopes.

Renewed interest

Despite considerable advances in radio astronomy and the increase in computing power since then, none of those projects has led to anything concrete. Some signals without identifiable origin have well been recorded, like the Wow! signal in 1977, but none of them has been repeated or seems credible enough to be attributable to alien life.

But that doesn’t mean scientists have given up. On the contrary, SETI has seen renewed interest following the discovery of the many exoplanets orbiting the billions of suns in our galaxy. Researchers have designed sophisticated new instruments — like the Square Kilometre Array, a giant radio telescope being built in South Africa and Australia with a total collecting area of one square kilometer — that could pave the way to promising breakthroughs. And Russian entrepreneur Yuri Milner recently announced an ambitious program called Breakthrough Listen, which aims to cover 10 times more sky than previous searches and scan a much wider band of frequencies. Milner intends to fund his initiative with 100 million dollars over 10 years.

“In reality, expanding the search to these magnitudes only increases our chances of finding something by very little. And if we still don’t detect any signals, we can’t necessarily conclude with much more certainty that there is no life out there,” says Grimaldi.

Still a ways to go

The advantage of Grimaldi’s statistical model is that it lets scientists interpret both the success and failure to detect signals at varying distances from Earth. His model employs Bayes’ theorem to calculate the remaining probability of detecting a signal within a given radius around our planet.

For example, even if no signal is detected within a radius of 1,000 light years, there is still an over 10% chance that Earth is within range of hundreds of similar signals from elsewhere in the galaxy, but that our radio telescopes are currently not powerful enough to detect them. However, that probability rises to nearly 100% if even just one signal is detected within the 1,000-light-year radius. In that case, we could be almost certain that our galaxy is full of alien life.

After factoring in other parameters like the size of the galaxy and how closely packed its stars are, Grimaldi estimates that the probability of detecting a signal becomes very slight only at a radius of 40,000 light years. In other words, if no signals are detected at this distance from Earth, we could reasonably conclude that no other civilization at the same level of technological development as ours is detectable in the galaxy. But so far, scientists have been able to search for signals within a radius of “just” 40 light years.

So there’s still a ways to go. Especially since these search methods can’t detect alien civilizations that may be in primordial stages or that are highly advanced but haven’t followed the same technological trajectory as ours.

Author: Sarah Perrin | Source: Ecole Polytechnique Fédérale de Lausanne [October 02, 2018]



Parker Solar Probe Successfully Completes First Venus Flyby

NASA – Parker Solar Probe Mission patch.

October 3, 2018

On Oct. 3, Parker Solar Probe successfully completed its flyby of Venus at a distance of about 1,500 miles during the first Venus gravity assist of the mission. These gravity assists will help the spacecraft tighten its orbit closer and closer to the Sun over the course of the mission.

Image above: The orbit design for the Parker Solar Probe mission. Image Credits: NASA/Johns Hopkins APL.

Detailed data from the flyby will be assessed over the next few days. This data allows the flight operations team to prepare for the remaining six Venus gravity assists which will occur over the course of the seven-year mission.

Related article:

Illuminating First Light Data from Parker Solar Probe:

Parker Solar Probe: https://www.nasa.gov/parkersolarprobe/

Image (mentioned), Text, Credits: NASA/Sarah Frazier.

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U.S., German Astronauts Swapping Command Before Homecoming

ISS – Expedition 56 Mission patch.

October 3, 2018

A NASA astronaut will swap command of the International Space Station with a European Space Agency (ESA) astronaut Wednesday at 10:10 a.m. live on NASA TV. Expedition 56 Commander Drew Feustel will be handing the station “keys” over to German astronaut Alexander Gerst during the traditional change of command ceremony.

Image above: Expedition 56 Commander Drew Feustel (left) of NASA will hand over command of the station to German astronaut Alexander Gerst of ESA. Image Credit: NASA.

Expedition 57 officially starts Thursday at 3:57 a.m. EDT when Feustel and Flight Engineer Ricky Arnold undock in the Soyuz MS-08 spacecraft commanded by cosmonaut Oleg Artemyev. Gerst, ESA’s second astronaut to command the station, is remaining onboard to lead Expedition 57 Flight Engineers Serena Auñón-Chancellor and Sergey Prokopyev. The homebound trio will parachute to a landing in Kazakhstan at 7:45 a.m. (5:45 p.m. Kazakhstan time) just two orbits after undocking and 197 days in space.

Astronaut Nick Hague from NASA’s astronaut class of 2014 and veteran station cosmonaut Alexey Ovchinin will be the next crew to blast off to the space station. The duo will launch Oct. 11 from the Baikonur Cosmodrome and take a six hour ride to their new home in space.

Image above: The Creativity of Mother Nature. International Space Station Commander Alexander Gerst has a better view of our home planet than most. From aboard the orbital laboratory he sees Earth in all its beauty and said of this image of the west coast of southern Africa: “Not many artists in this world are as creative as Mother Nature.” Image Credits: ESA/NASA-A.Gerst.

Amidst the crew departure activities today the station residents also worked space science and lab maintenance. Auñón-Chancellor worked on botany research inside the Plant Habitat located in the Columbus lab module. Gerst worked on hardware for the mobiPV study that is researching ways to increase productivity between astronauts and mission controllers. Departing astronauts Arnold and Feustel cleaned up their crew quarters.

Related links:

Expedition 56: https://www.nasa.gov/mission_pages/station/expeditions/expedition56/index.html

Expedition 57: https://www.nasa.gov/mission_pages/station/expeditions/expedition57/index.html

Plant Habitat: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=2036

MobiPV: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1818

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/Yvette Smith/Mark Garcia.

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Global warming increases wildfire potential damages in Mediterranean Europe

A study published in Nature Communications, led by researchers of the University of Barcelona in collaboration with other research institutions, shows that anthropogenic warming will increase the burned areas due fires in Mediterranean Europe, and the increase of the burned area could be reduced by limiting global warming to 1.5 ºC. The higher the warming level is, the larger the increase of the burned area is.

Global warming increases wildfire potential damages in Mediterranean Europe
Simulation of the burned area for global warming cases of an increase by 1.5 ºC, 2 ºC and 3 ºC. On the left side, a case
applying the stationary model (SM), and the case with a non-stationary model (NSM) at the right. Dots show the areas
 where at least the 50 % of simulations show a statistically significant change [Credit: Marco Turco et al.]

“To draw this conclusion we combined regional climate projections with several empirical models linking the summer burned area to key climatic drivers”, notes Marco Turco, UB researcher and first author of the study. “These results support the statement of the Paris Agreement (2015) that reports that limiting the temperature increase to 1.5 ºC would “significantly reduce the risks and impacts of climate change”, says the researcher.
Fire seasons in 2017 and 2018 have been unusually high in several regions in Europe, with large wildfires in Greece, Portugal and Sweden, associated with intense droughts and heatwaves. These fires caused economic and ecological losses, and even human casualties.

Global warming increases wildfire potential damages in Mediterranean Europe
Simulation of the burned area for global warming cases of an increase by 1.5 ºC, 2 ºC and 3 ºC. On the left side, a case
applying the stationary model (SM), and the case with a non-stationary model (NSM) at the right. Dots show the areas
 where at least the 50 % of simulations show a statistically significant change [Credit: Marco Turco et al.]

Marco Turco and his team used a series of regional climate models to project burned area in Mediterranean Europe, taking into account how the climate-vegetation-fire relationship will change under different scenarios due other factors such as droughts. The authors find that, with a 1.5 º C global warming, the burned area could increase by 40 % compared the projections that do not take into account future warming (mainly in the Iberian Peninsula). If warming is at 3 ºC, it would increase by 100 %.
“These results, combined with the increase in societal exposure to large wildfires in recent years, call for a rethinking of current management strategies. Climate change effects could overcome fire prevention efforts, implying that more fire management efforts must be planned in the near future”, says Marco Turco, researcher in the Group of Analysis of Adverse Weather Situations (GAMA) of the University of Barcelona, led by Carme Llasat, lecturer at the Department of Applied Physics of the UB. In this sense, the development of climate-fire models is crucial to identify key actions in adaptation strategies. In particular, combined with seasonal climate forecasts, these offer an under-exploited opportunity to prevent and reduce the fire impact of climate adverse conditions.

Source: University of Barcelona [October 02, 2018]




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