четверг, 31 января 2019 г.

Hubble fortuitously discovers a new galaxy in the cosmic neighbourhood

The accidentally discovered galaxy Bedin I

Bedin 1 in NGC 6752

Globular cluster NGC 6752

Wide-field view of NGC 6752 (ground-based view)


Zooming in on NGC 6752 and Bedin 1

Zooming in on NGC 6752 and Bedin 1

Flight to Bedin 1

Flight to Bedin 1

Astronomers using the NASA/ESA Hubble Space Telescope to study some of the oldest and faintest stars in the globular cluster NGC 6752 have made an unexpected finding. They discovered a dwarf galaxy in our cosmic backyard, only 30 million light-years away. The finding is reported in the journal Monthly Notices of the Royal Astronomical Society: Letters.

An international team of astronomers recently used the NASA/ESA Hubble Space Telescope to study white dwarf stars within the globular cluster NGC 6752. The aim of their observations was to use these stars to measure the age of the globular cluster, but in the process they made an unexpected discovery.

In the outer fringes of the area observed with Hubble’s Advanced Camera for Surveys a compact collection of stars was visible. After a careful analysis of their brightnesses and temperatures, the astronomers concluded that these stars did not belong to the cluster — which is part of the Milky Way — but rather they are millions of light-years more distant.

Our newly discovered cosmic neighbour, nicknamed Bedin 1 by the astronomers, is a modestly sized, elongated galaxy. It measures only around 3000 light-years at its greatest extent — a fraction of the size of the Milky Way. Not only is it tiny, but it is also incredibly faint. These properties led astronomers to classify it as a dwarf spheroidal galaxy.

Dwarf spheroidal galaxies are defined by their small size, low-luminosity, lack of dust and old stellar populations [1]. 36 galaxies of this type are already known to exist in the Local Group of Galaxies, 22 of which are satellite galaxies of the Milky Way.

While dwarf spheroidal galaxies are not uncommon, Bedin 1 has some notable features. Not only is it one of just a few dwarf spheroidals that have a well established distance but it is also extremely isolated. It lies about 30 million light-years from the Milky Way and 2 million light-years from the nearest plausible large galaxy host, NGC 6744. This makes it possibly the most isolated small dwarf galaxy discovered to date.

From the properties of its stars, astronomers were able to infer that the galaxy is around 13 billion years old — nearly as old as the Universe itself. Because of its isolation — which resulted in hardly any interaction with other galaxies — and its age, Bedin 1 is the astronomical equivalent of a living fossil from the early Universe.

The discovery of Bedin 1 was a truly serendipitous find. Very few Hubble images allow such faint objects to be seen, and they cover only a small area of the sky. Future telescopes with a large field of view, such as the WFIRST telescope, will have cameras covering a much larger area of the sky and may find many more of these galactic neighbours.


[1] While similar to dwarf elliptical galaxies in appearance and properties, dwarf spheroidal galaxies are in general approximately spherical in shape and have a lower luminosity.

More Information

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

The results were presented in the letter The HST Large Programme on NGC 6752. I. Serendipitous discovery of a dwarf galaxy in background, published in the journal Monthly Notices of the Royal Astronomical Society: Letters.

The international team of astronomers that carried out this study consists of L. R. Bedin (INAF-Osservatorio Astronomico di Padova, Italy), M. Salaris (Liverpool John Moores University, UK), R. M. Rich (University of California Los Angeles, USA), H. Richer (University of British Columbia), J. Anderson (Space Telescope Science Institute, USA), B. Bettoni (INAF-Osservatorio Astronomico di Padova, Italy), D. Nardiello (Università di Padova, Italy), A. P. Milone (Università di Padova, Italy), A. F. Marino (Università di Padova, Italy), M. Libralato (Space Telescope Science Institute, USA), A. Bellini (Space Telescope Science Institute, USA), A. Dieball (University of Bonn, Germany), P. Bergeron (Université de Montréal, Canada), A. J. Burgasser (University of California San Diego, USA), D. Apai (University of Arizona, USA).

Image credit: NASA, ESA, Bedin et al.



L. R. Bedin
INAF-Osservatorio Astronomico di Padova
Padua, Italy
Tel: +49 8293 413

Email: luigi.bedin@oapd.inaf.it

Mathias Jäger
ESA/Hubble, Public Information Officer
Garching, Germany
Tel: +49 176 62397500

Archive link

2019 January 31 Sharpless 308: Star Bubble Image Credit &…

2019 January 31

Sharpless 308: Star Bubble
Image Credit & Copyright: Laubing

Explanation: Blown by fast winds from a hot, massive star, this cosmic bubble is huge. Cataloged as Sharpless 2-308 it lies some 5,200 light-years away toward the constellation of the Big Dog (Canis Major) and covers slightly more of the sky than a Full Moon. That corresponds to a diameter of 60 light-years at its estimated distance. The massive star that created the bubble, a Wolf-Rayet star, is the bright one near the center of the nebula. Wolf-Rayet stars have over 20 times the mass of the Sun and are thought to be in a brief, pre-supernova phase of massive star evolution. Fast winds from this Wolf-Rayet star create the bubble-shaped nebula as they sweep up slower moving material from an earlier phase of evolution. The windblown nebula has an age of about 70,000 years. Relatively faint emission captured in the expansive image is dominated by the glow of ionized oxygen atoms mapped to a blue hue. SH2-308 is also known as The Dolphin Nebula.

∞ Source: apod.nasa.gov/apod/ap190131.html

Lunar rock samples retrieved by astronauts almost 50 years ago likely originated on Earth

In findings published in science journal Earth and Planetary Science Letters, a sample collected during the 1971 Apollo 14 lunar mission was found to contain traces of minerals with a chemical composition common to Earth and very unusual for the moon.

Lunar rock samples retrieved by astronauts almost 50 years ago likely originated on Earth
A lunar rock sample collected on the Apollo 14 mission [Credit: NASA]

The sample was on loan from NASA to Curtin University, where it was investigated in cooperation with researchers from the Swedish Museum of Natural History, Australian National University and Lunar and Planetary Institute in Houston.

Research author Professor Alexander Nemchin, from Curtin’s School of Earth and Planetary Sciences, said the 1.8 gram sample showed mineralogy similar to that of a granite, which is extremely rare on the moon but common on Earth.

“The sample also contains quartz, which is an even more unusual find on the moon,” Professor Nemchin said.

“By determining the age of zircon found in the sample, we were able to pinpoint the age of the host rock at about four billion years old, making it similar to the oldest rocks on Earth.

“In addition, the chemistry of the zircon in this sample is very different from that of every other zircon grain ever analysed in lunar samples, and remarkably similar to that of zircons found on Earth.”

Professor Nemchin said the chemistry of the zircon lunar sample indicated that it formed at low temperature and probably in the presence of water and at oxidised conditions, making it characteristic of Earth and highly irregular for the moon.

“It is possible that some of these unusual conditions could have occurred very locally and very briefly on the moon and the sample is a result of this brief deviation from normality,” Professor Nemchin said.

“However, a simpler explanation is that this piece was formed on the Earth and brought to the surface of the moon as a meteorite generated by an asteroid hitting Earth about four billion years ago, and throwing material into space and to the moon.

“Further impacts on the moon at later times would have mixed the Earth rocks with lunar rocks, including at the future Apollo 14 landing site, where it was collected by astronauts and brought back home to the Earth.”

Author: Lucien Wilkinson | Source: Curtin University [January 25, 2019]



Roman remains unearthed near famous Lisbon restaurant

Portuguese archaeologists digging near one of Lisbon’s most iconic restaurants, the Solar dos Presuntos (Manor of Hams), have discovered a large Roman cemetery holding 2,000-year-old skeletons and various ancient artifacts.

Roman remains unearthed near famous Lisbon restaurant

Roman remains unearthed near famous Lisbon restaurant
Roman inhumation burials with grave goods [Credit: DR]

The necropolis was found after the restaurant owners decided to expand their establishment, founded in 1974 in Lisbon’s historical center.
To get the expansion project approved, city authorities required that a team of archaeologists first survey the land.

Roman remains unearthed near famous Lisbon restaurant

Roman remains unearthed near famous Lisbon restaurant
Skeletal remains from ancient Roman cemetery in Lisbon [Credit: Pedro Nunes/Reuters]

“What we found was a big surprise,” said Nuno Neto, an archaeologist at Neoepica, the company that carried out the digging at a depth of around six meters (20 ft). “The level of preservation is excellent, and the set of artifacts is fabulous.”
The necropolis was found to hold 25 skeletons, 35 sets of cremated remains, pottery and coins used in ancient burial rituals. All have been moved to Neoepica’s research laboratory, which will eventually transfer them to the city council.

Roman remains unearthed near famous Lisbon restaurant

Roman remains unearthed near famous Lisbon restaurant
Roman-era pottery and other finds found in the graves [Credit: Pedro Nunes/Reuters]

The findings were only made public last month, but archaeologists have been working on the site since 2016.
Work on expanding the restaurant has already started, and despite the delays, the owners see the discovery of the Roman cemetery as something positive and hope to have some of the ancient items on display in the future.

Roman armies occupied Olissipo, as Lisbon used to be known, around 200 BC and it remained under Roman control for several centuries.

Source: Reuters [January 26, 2019]



Huge Cavity in Antarctic Glacier Signals Rapid Decay

NASA – Operation IceBridge Mission patch.

January 30, 2019

A gigantic cavity – two-thirds the area of Manhattan and almost 1,000 feet (300 meters) tall – growing at the bottom of Thwaites Glacier in West Antarctica is one of several disturbing discoveries reported in a new NASA-led study of the disintegrating glacier. The findings highlight the need for detailed observations of Antarctic glaciers’ undersides in calculating how fast global sea levels will rise in response to climate change.

Researchers expected to find some gaps between ice and bedrock at Thwaites’ bottom where ocean water could flow in and melt the glacier from below. The size and explosive growth rate of the newfound hole, however, surprised them. It’s big enough to have contained 14 billion tons of ice, and most of that ice melted over the last three years.

Thwaites Glacier. Image Credit: NASA/OIB/Jeremy Harbeck

“We have suspected for years that Thwaites was not tightly attached to the bedrock beneath it,” said Eric Rignot of the University of California, Irvine, and NASA’s Jet Propulsion Laboratory in Pasadena, California. Rignot is a co-author of the new study, which was published today in Science Advances. “Thanks to a new generation of satellites, we can finally see the detail,” he said.

The cavity was revealed by ice-penetrating radar in NASA’s Operation IceBridge, an airborne campaign beginning in 2010 that studies connections between the polar regions and the global climate. The researchers also used data from a constellation of Italian and German spaceborne synthetic aperture radars. These very high-resolution data can be processed by a technique called radar interferometry to reveal how the ground surface below has moved between images.

“[The size of] a cavity under a glacier plays an important role in melting,” said the study’s lead author, Pietro Milillo of JPL. “As more heat and water get under the glacier, it melts faster.”

Numerical models of ice sheets use a fixed shape to represent a cavity under the ice, rather than allowing the cavity to change and grow. The new discovery implies that this limitation most likely causes those models to underestimate how fast Thwaites is losing ice.

About the size of Florida, Thwaites Glacier is currently responsible for approximately 4 percent of global sea level rise. It holds enough ice to raise the world ocean a little over 2 feet (65 centimeters) and backstops neighboring glaciers that would raise sea levels an additional 8 feet (2.4 meters) if all the ice were lost.

Animation above: Changes in surface height at Thwaites Glacier’s grounding line, 2011 to 2017, with sinking areas in red and rising areas in blue. The growing cavity (red mass, center) caused the greatest sinking. The mottled area (bottom left) is the site of extensive calving. Contours show bedrock topography. Animation Credits: NASA/JPL-Caltech.

Thwaites is one of the hardest places to reach on Earth, but it is about to become better known than ever before. The U.S. National Science Foundation and British National Environmental Research Council are mounting a five-year field project to answer the most critical questions about its processes and features. The International Thwaites Glacier Collaboration will begin its field experiments in the Southern Hemisphere summer of 2019-20.

How Scientists Measure Ice Loss

There’s no way to monitor Antarctic glaciers from ground level over the long term. Instead, scientists use satellite or airborne instrument data to observe features that change as a glacier melts, such as its flow speed and surface height.

Another changing feature is a glacier’s grounding line – the place near the edge of the continent where it lifts off its bed and starts to float on seawater. Many Antarctic glaciers extend for miles beyond their grounding lines, floating out over the open ocean.

Just as a grounded boat can float again when the weight of its cargo is removed, a glacier that loses ice weight can float over land where it used to stick. When this happens, the grounding line retreats inland. That exposes more of a glacier’s underside to sea water, increasing the likelihood its melt rate will accelerate.

An Irregular Retreat

For Thwaites, “We are discovering different mechanisms of retreat,” Millilo said. Different processes at various parts of the 100-mile-long (160-kilometer-long) front of the glacier are putting the rates of grounding-line retreat and of ice loss out of sync.

The huge cavity is under the main trunk of the glacier on its western side – the side farther from the West Antarctic Peninsula. In this region, as the tide rises and falls, the grounding line retreats and advances across a zone of about 2 to 3 miles (3 to 5 kilometers). The glacier has been coming unstuck from a ridge in the bedrock at a steady rate of about 0.4 to 0.5 miles (0.6 to 0.8 kilometers) a year since 1992. Despite this stable rate of grounding-line retreat, the melt rate on this side of the glacier is extremely high.

“On the eastern side of the glacier, the grounding-line retreat proceeds through small channels, maybe a kilometer wide, like fingers reaching beneath the glacier to melt it from below,” Milillo said. In that region, the rate of grounding-line retreat doubled from about 0.4 miles (0.6 kilometers) a year from 1992 to 2011 to 0.8 miles (1.2 kilometers) a year from 2011 to 2017. Even with this accelerating retreat, however, melt rates on this side of the glacier are lower than on the western side.

These results highlight that ice-ocean interactions are more complex than previously understood.

Milillo hopes the new results will be useful for the International Thwaites Glacier Collaboration researchers as they prepare for their fieldwork. “Such data is essential for field parties to focus on areas where the action is, because the grounding line is retreating rapidly with complex spatial patterns,” he said.

“Understanding the details of how the ocean melts away this glacier is essential to project its impact on sea level rise in the coming decades,” Rignot said.

The paper by Milillo and his co-authors in the journal Science Advances is titled “Heterogeneous retreat and ice melt of Thwaites Glacier, West Antarctica.” Co-authors were from the University of California, Irvine; the German Aerospace Center in Munich, Germany; and the University Grenoble Alpes in Grenoble, France.

Related links:

Operation IceBridge: https://www.nasa.gov/mission_pages/icebridge/index.html

International Thwaites Glacier Collaboration: https://thwaitesglacier.org/

Image (mentioned), Animation (mentioned), Text, Credits: NASA/JPL/Esprit Smith/University of California/Brian Bell/NASA’s Earth Science News Team, written by Carol Rasmussen.

Greetings, Orbiter.chArchive link

Crew Works CubeSats, Life Science and Configures Physics Hardware

ISS – Expedition 58 Mission patch.

January 30, 2019

The International Space Station is set to deploy a new series of CubeSats as the Expedition 58 crew configures research hardware to enable a variety of space experiments.

Japan’s Kibo laboratory module airlock has been set up with a small satellite deployer loaded with several CubeSats. Astronaut Anne McClain finished the installation work Wednesday, depressurized the airlock and maneuvered the deployer outside Kibo.

Image above: Portions of Cuba, The Bahamas and the Turks and Caicos Islands are viewed from the International Space Station as the orbital complex flew 252 miles above the Atlantic Ocean. At left, is the aft end of the Progress 70 resupply ship from Russia attached to the Pirs docking compartment. Image Credit: NASA.

She and fellow astronaut David Saint-Jacques will monitor and photograph the CubeSat deployments planned for Thursday around noon EST. The CubeSats will study Earth’s ionosphere and satellite communication techniques.

McClain next inventoried Rodent Research gear trashing some hardware to make extra space aboard the lab. She later swapped a hard drive on a laptop computer dedicated to meteor observations then attached sensors to her head and chest for the Circadian Rhythms study.

International Space Station (ISS). Animation Credit: NASA

Saint-Jacques installed new electronics on the Kubik incubator upgrading the device that houses biology experiments on seeds, cells and small animals. He later swapped parts in the Combustion Integrated Rack that permits safe research into fuel and flames aboard the orbital lab.

Commander Oleg Kononenko started Wednesday researching microgravity’s effect on heart rate and breathing. He later explored advanced photography tools and techniques to better detect targets of interest on Earth.

Related links:

Expedition 58: https://www.nasa.gov/mission_pages/station/expeditions/expedition58/index.html

Kibo laboratory module: https://www.nasa.gov/mission_pages/station/structure/elements/japan-kibo-laboratory

CubeSats: https://www.nasa.gov/mission_pages/cubesats/index.html

Rodent Research: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7735

Meteor: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1174

Circadian Rhythms: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=869

Kubik: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=894

Advanced photography tools and techniques: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1469

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

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

Best regards, Orbiter.chArchive link

Fluorite | #Geology #GeologyPage #Mineral Locality: Ruguan…

Fluorite | #Geology #GeologyPage #Mineral

Locality: Ruguan Mine, China

Size: 8.8 x 6.8 x 6.8 cm

Photo Copyright © Anton Watzl Minerals

Geology Page



Svartifoss Waterfall, Iceland | #Geology #GeologyPage…

Svartifoss Waterfall, Iceland | #Geology #GeologyPage #Iceland

Svartifoss (Black Falls) is a waterfall in Skaftafell in Vatnajökull National Park in Iceland, and is one of the most popular sights in the park. It is surrounded by dark lava columns, which gave rise to its name.

The base of this waterfall is noteworthy for its sharp rocks. New hexagonal column sections break off faster than the falling water wears down the edges.

Geology Page



Graeco-Roman wine storage rooms discovered in Egypt’s Beheira

The archaeological mission of the Supreme Council of Antiquities working at Tel Kom al Trogy in Al-Bihera Governorate brought to light the third section of a winery with its storage cells.

Graeco-Roman wine storage rooms discovered in Egypt's Beheira
The storage cells [Credit: Egypt. Ministry of Antiquities]

Secretary General of the Supreme Council of Antiquities Dr. Mostafa Waziri said that the storage galleries have a very distinguished architectural style. They were built with thick mudbrick walls. Limestone slabs of different sizes were added to the walls. Archaeologists believe that this was done to cool the rooms for the storage of the wine.
Head of ancient Egyptian artefacts for the Ministry of Antiquities, Dr. Ayman Ashmawy said that the area was well known for its high quality wine, which was considered as the finest wine during the Graeco-Roman time.

Graeco-Roman wine storage rooms discovered in Egypt's Beheira

Graeco-Roman wine storage rooms discovered in Egypt's Beheira

Graeco-Roman wine storage rooms discovered in Egypt's Beheira

Graeco-Roman wine storage rooms discovered in Egypt's Beheira

Graeco-Roman wine storage rooms discovered in Egypt's Beheira

Graeco-Roman wine storage rooms discovered in Egypt's Beheira

Graeco-Roman wine storage rooms discovered in Egypt's Beheira
Finds at Tel Kom al Trogy in Al-Bihera Governorate
[Credit: Egypt. Ministry of Antiquities]

Dr. Ashmawy pointed out that fragments of mosaic and painted wall at the site indicate the existence of other buildings in the complex that have not been located yet. These building may have been used for the supervisors and the employees of the winery.

A collection of  kilns,  pottery, and coins from the Ptolemaic era until the Islamic period were also unearthed.

Source: Egypt. Ministry of Antiquities [January 27, 2019]



Reassembling ancient Cypriot artefacts scattered across the globe

How do you assemble an ancient statue, when the head is the property of a museum in the UK, the feet are in a Sweden and the rest of its body is in Cyprus?

Reassembling ancient Cypriot artefacts scattered across the globe
Terracotta figures on display at the Cyprus Museum
[Credit: Cyprus Mail]

Not an easy feat, as museums are not likely to give up what they consider to be part of their very own collection, even when the objects come from another country. The reason they think of them as their own is often that the archaeologists who participated in the excavations in foreign countries then took artefacts which they had unearthed home with them.

For example, Swedish archaeologists worked in the 20th century in different places in Cyprus and as pieces that are found are rarely intact, they might have, as associate professor Sorin Hermon, of the Cyprus Institute’s research group on digital cultural heritage put it, “ended up with one hand of a statue while the foot was still in Cyprus”.

This is where the Gravitate project comes in, a four-year initiative funded by the European Commission, in which the Cyprus Institute participated as one of its six international partners.

“The project had an ambitious scope,” Hermon said, “to address important challenges when it comes to research broken artefacts, fragmented objects or collections dispersed around the world.”

Reassembling ancient Cypriot artefacts scattered across the globe
Head fragment from Salamis in the British Museum
[Credit: Cyprus Mail]

The first thing the researchers did was to travel around Europe, scanning fragments in museums believed to be part of collections they were interested in with a 3D scanner. They then created three-dimensional models from the data they collected.

“We now have a repository of more than 250 fragments belonging to probably around 30 statues,” the professor explained.

The problem of how to assemble them is solved by digital technology used as part of the project.

The Gravitate project partners developed a set of software tools, a toolkit that allowed the professionals to identify and reunify the artefacts, establish a relationship and, if possible, reassemble fragments belonging to the same object.

“In a real collection it is impossible to have these 250 objects on one table, but in the digital world it is possible to have them on one virtual table.”

Using the digital toolkit, other aspects such as the colour and material were examined, helping the researchers to determine what belongs where. “It is proof of where the fragments belong,” Hermon said.

Reassembling ancient Cypriot artefacts scattered across the globe
Foot fragment from Salamis in the Cyprus Museum
[Credit: Cyprus Mail]

One part of the dataset are terracotta statues from Salamis.

“Salamis was excavated more than 100 years ago and the British took a lot of artefacts to the British museum,” said Hermon. “Others are displayed in the Oxford and Cambridge universities museums.”

He said these terracotta statues are actually extremely important, as they are very old and people don’t know much about them.

“If you have in mind the famous terracotta soldiers of China, we are talking about similar objects from Cyprus.”

Fragments from frescos looted from Cyprus churches and monasteries are another part of the set.

While the front shows patterns and colours, it is possible to see where and how they fit on a church wall and how they should be put back there by examining the back.

This reunification, reassociation and reassembly is the innovative part of the project, or the useful application.

Reassembling ancient Cypriot artefacts scattered across the globe
3D replicas of terracotta statue at the Cyprus Institute
[Credit: Cyprus Mail]

Hermon believes the project has achieved a lot more for Cyprus.

“It has a direct relevance to the Cyprus heritage,” the assistant professor stressed. “There are many collections abroad and the technology developed will make the conservation and restoration of these artefacts much easier.”

From this, not only curators and researchers benefit, but it is also possible to create new kinds of exhibitions, which give the public the chance of learning more about the historical and cultural past of their country.

It is also important that a Cyprus research organisation has been part of a big prestigious European project and has become a competence centre for the expertise gathered, Hermon concluded.

The IT Innovation Centre (UK), the British Museum, The Cyprus Institute, Consiglio Nazionale delle Ricerche with its Institute of Applied Mathematics and Information Technologies in Italy, the University of Amsterdam and Technion – the Israel Institute of Technology at the University of Haifa, are the six partners which took part in the European Commission funded project.

Author: Annette Chrysostomou | Source: Cyprus Mail [January 27, 2019]



Missing-link in planet evolution found

For the first time ever, astronomers have detected a 1.3 km radius body at the edge of the Solar System. Kilometer sized bodies like the one discovered have been predicted to exist for more than 70 years. These objects acted as an important step in the planet formation process between small initial amalgamations of dust and ice and the planets we see today.

Missing-link in planet evolution found
Artist’s impression of the newly discovered object [Credit: Ko Arimatsu]

The Edgeworth-Kuiper Belt is a collection of small celestial bodies located beyond Neptune’s orbit. The most famous Edgeworth-Kuiper Belt Object is Pluto. Edgeworth-Kuiper Belt Objects are believed to be remnants left over from the formation of the Solar System. While small bodies like asteroids in the inner Solar System have been altered by solar radiation, collisions, and the gravity of the planets over time; objects in the cold, dark, lonely Edgeworth-Kuiper Belt preserve the pristine conditions of the early Solar System. Thus astronomers study them to learn about the beginning of the planet formation process.
Edgeworth-Kuiper Belt Objects with radii from 1 kilometer to several kilometers have been predicted to exist, but they are too distant, small, and dim for even world-leading telescopes, like the Subaru Telescope, to observe directly. So a research team led by Ko Arimatsu at the National Astronomical Observatory of Japan used a technique known as occultation: monitoring a large number of stars and watching for the shadow of an object passing in front of one of the stars. The OASES (Organized Autotelescopes for Serendipitous Event Survey) team placed two small (28 cm) telescopes on the roof of the Miyako open-air school on Miyako Island, Miyakojima-shi, Okinawa Prefecture, Japan, and monitored approximately 2000 stars for a total of 60 hours.
Analyzing the data, the team found an event consistent with a star appearing to dim as it is occulted by a 1.3 km radius Edgeworth-Kuiper Belt Object. This detection indicates that kilometer sized Edgeworth-Kuiper Belt Objects are more numerous than previously thought. This supports models where planetesimals first grow slowly into kilometer sized objects before runaway growth causes them to merge into planets.
Arimatsu explains, “This is a real victory for little projects. Our team had less than 0.3% of the budget of large international projects. We didn’t even have enough money to build a second dome to protect our second telescope! Yet we still managed to make a discovery that is impossible for the big projects. Now that we know our system works, we will investigate the Edgeworth-Kuiper Belt in more detail. We also have our sights set on the still undiscovered Oort Cloud out beyond that.”

The findings are published in Nature Astronomy.

Source: National Institutes of Natural Sciences [January 28, 2019]



Molecular analysis of anchiornis feather gives clues to origin of flight

An international team of researchers has performed molecular analysis on fossil feathers from a small, feathered dinosaur from the Jurassic. Their research could aid scientists in pinpointing when feathers evolved the capacity for flight during the dinosaur-bird transition.

Molecular analysis of anchiornis feather gives clues to origin of flight
This is the Anchiornis specimen studied in this work [Credit: WANG Xiaoli]

Anchiornis was a small, feathered, four-winged dinosaur that lived in what is now China around 160 million years ago — almost 10 million years before Archaeopteryx, the first recognized bird. A team of researchers from the Nanjing Institute of Geology and Paleontology, North Carolina State University, and the University of South Carolina analyzed Anchiornis feathers to see how they differed at the molecular level from those of younger fossil birds and modern birds.
“Modern bird feathers are composed primarily of beta-keratin (β-keratin), a protein also found in skin, claws, and beaks of reptiles and birds. Feathers differ from these other β-keratin containing tissues, because the feather protein is modified in a way that makes them more flexible,” says Mary Schweitzer, professor of biological sciences at NC State with a joint appointment at the North Carolina Museum of Natural Sciences and co-author of a paper describing the research.

“At some point during the evolution of feathers, one of the β-keratin genes underwent a deletion event, making the resultant protein slightly smaller. This deletion changed the biophysics of the feather to something more flexible — a requirement for flight. If we can pinpoint when, and in what organisms, that deletion event occurred, we will have a better grasp on when flight evolved during the transition from dinosaurs to birds.”

Molecular analysis of anchiornis feather gives clues to origin of flight
This is a TEM image of the fossilized feather from the Anchiornis specimen [Credit: NIGPAS]

The researchers, led by Yanhong Pan, a visiting researcher from the Nanjing Institute, examined fossilized feathers from Anchiornis, using high-resolution electron microscopy, as well as multiple chemical and immunological techniques to determine the molecular composition of the feathers. They did the same to other feathers from the Mesozoic and Cenozoic eras, as well as other β-keratin tissues not expected to show this deletion, then compared results with modern bird feathers and tissues.
They found that Anchiornis feathers were comprised of both β-keratins and alpha-keratins (α-keratins), a protein all terrestrial vertebrates have, including mammals. This was surprising because α-keratin is present in only small amounts in modern feathers. In addition to co-expressing both keratin proteins, the Anchiornis feathers had already undergone the deletion event that sets feathers apart from other tissues.

“Molecular clocks, which scientists use as benchmarks for evolutionary and genetic divergence, predict that the deletion, and thus functional flight feathers, evolved around 145 million years ago,” Schweitzer says. “Anchiornis is millions of years older, yet has the shortened protein form. This work shows that we can utilize molecular fossil data to root molecular clocks and improve their accuracy — we can start to put timing on genetic events in the dinosaur-bird transition via absence or presence of these two keratins. The data also give us more information about how feathers evolved to enable flight.”

The work appears in Proceedings of the National Academy of Sciences.

Author: Tracey Peake | Source: North Carolina State University [January 28, 2019]



Earth’s continental nurseries discovered beneath mountains

In his free time last summer, Rice University geoscientist Ming Tang made a habit of comparing the niobium content in various rocks in a global minerals database. What he found was worth skipping a few nights out with friends.

Earth's continental nurseries discovered beneath mountains
The central Andes Mountains and surrounding landscape, as seen in this true-colour image from NASA’s Terra spacecraft,
formed over the past 170 million years as the Nazca Plate lying under the Pacific Ocean has forced its way
under the South American Plate [Credit: NASA]

In a paper published this month by Nature Communications, Tang, Rice petrologist Cin-Ty Lee and colleagues offered an answer to one of Earth science’s fundamental questions: Where do continents form?

“If our conclusions are correct, every piece of land that we are now sitting on got its start someplace like the Andes or Tibet, with very mountainous surfaces,” said Tang, lead author of the study and a postdoctoral research associate in Rice’s Department of Earth, Environmental and Planetary Sciences (EEPS). “Today, most places are flat because that is the stable stage of the continental crust. But what we found was that when the crust formed, it had to start out with mountain-building processes.”

The connection between niobium, one of Earth’s rarest elements, and continent formation is a story that plays out over billions of years at scales as small as molecules and as large as mountain ranges. The leading players are niobium and tantalum, rare metals so alike that geologists often think of them as twins.

“They have very similar chemical properties and behave almost identically in most geological processes,” Tang said. “If you measure tantalum and niobium, you find that their ratio is nearly constant in Earth’s mantle. That means that when you find more niobium in a rock, you will find more tantalum, and when you find less niobium, you will find less tantalum.”

The mantle is Earth’s thickest layer, spanning about 1,800 miles between the planet’s core and its thin outer crust. Earth scientists believe that little, if anything, moves between the mantle and core, but the mantle and everything above it — seafloor, oceans, continents and atmosphere — are connected, and many of the atoms on Earth’s surface today, including the atoms in humans and other living things, have cycled through the mantle one or more times in Earth’s 4.6 billion years.

The rocks in continents are an exception. Geologists have found some that are up to 4 billion years old, which means they were formed near the surface and stayed on the surface, without being recycled into the mantle. That’s due in part to the nature of continental crust, which is far less dense than the basaltic rocks beneath Earth’s oceans. Lee, professor and EEPS department chair, said it’s no coincidence that Earth is the only rocky planet known to have both continents and life.

“Every day we live on continents, and we take most of our resources from continents,” Lee said. “We have oxygen in the air to breath and just the right temperature to support complex life. These things are so common that we take them for granted, but Earth didn’t start off with these conditions. They developed later in Earth’s history. And the emergence of continents is one of the things that shaped our planet and made it more livable.”

Scientists still lack details about how continents got their start and how they grew to cover 30 percent of Earth’s surface, but one big clue relates to niobium and tantalum, the geochemical twins.

“On average, the rocks in continental crust have about 20 percent less niobium than they should compared to the rock we see everywhere else,” Tang said. “We believe this missing niobium is tied to the mystery of continents. By solving or finding the missing the niobium, we can get important information about how continents form.”

Geologists have known about the imbalance for decades. And it certainly suggests that the geochemical processes that produce continental crust also remove niobium. But where was the missing niobium?

That nagging question prompted Tang to spend his free time perusing records in the Max Planck Institute’s GEOROC database, a comprehensive global collection of published analyses of volcanic rocks.

Based on those searches and months of follow-up tests, Tang, Lee and colleagues offer the first physical evidence that “arclogites” (pronounced ARC-loh-jyts) are responsible for the missing niobium. Arclogites are cumulates, the leftover dross that accumulates near the base of continental arcs. On rare occasions, chunks of these cumulates erupt onto the surface from volcanos.

The Rice group first sent arclogite samples that Lee had collected in Arizona to their collaborator, Kang Chen, a research fellow based at the China University of Geosciences in Wuhan. Chen spent a month getting precise readings of the relative amounts of niobium and tantalum in the samples. The rocks were created when the High Sierras were an active continental arc, like the Andes today.

Chen’s tests confirmed high niobium-tantalum ratios, but to better understand the mechanism by which this signature was developed, Tang and Lee used high precision laser ablation and “inductively coupled plasma mass spectrometry” in Lee’s laboratory at Rice to reveal the mineral rutile was responsible.

“Rutile is the mineral that hosts the niobium,” he said. “It’s a naturally occurring form of titanium oxide, and it is what actually ‘sees’ the difference between niobium and tantalum and captures one more than the other.”

But that happens only under specific conditions. For example, Tang said that at temperatures above 1,000 degrees Celsius, rutile traps normal ratios of tantalum and niobium. It only begins to prefer niobium when temperatures drop below 1,000 degrees Celsius. Tang said the only known place with that set of conditions is deep beneath continental arcs, like the Andes today or the High Sierras about 80 million years ago.

“The reason you need high pressure is that titanium oxide is relatively rare,” he said. “You need very high pressure to force it to crystalize and fall out of the magma.”

In an earlier arclogite study published in Science Advances, Tang and Lee discovered a subtle chemical signature that can explain why continental crust is iron-depleted. Lee said that finding and the discovery about rutile and niobium illustrate the central importance of continental arcs in Earth history.

“Continental arcs are like a magic system that links everything together, from climate and oxygen concentrations in the atmosphere to ore deposits,” Lee said. “They’re a sink for carbon dioxide after they die. They can drive greenhouse or icehouse, and they are the building blocks of continents.”

Author: Jade Boyd | Source: Rice University [January 29, 2019]



New family of fungi threatens a UNESCO-listed 8-century-old cathedral in Portugal

To be listed as UNESCO World Heritage requires special care and protection of valuable cultural monuments and pieces of Art from threats such as biodeterioration caused by microcolonial black fungi. The culprits lodge their branch-like structures (hyphae) deep into the stone forming fissures and cracks and also produce polysaccharides that trigger corrosion.

New family of fungi threatens a UNESCO-listed 8-century-old cathedral in Portugal
This is the sampling site, the Old Cathedral of Coimbra (Sé Velha de Coimbra)
in Portugal [Credit: Miguel Mesquita]

These fungi are well known for their unique resistance to hostile environmental conditions, including extreme temperatures, high solar and UV radiation, severe droughts and low abundance of nutrients. As a result, they survive in hot and cold deserts, saltpans, acidic and hydrocarbon-contaminated sites and exposed rocks surfaces. All of this makes them a particular challenge to conservationists and biologists who care for historic monuments.
During a multi-disciplinary scientific survey at the 8-century-old cathedral Sé Velha de Coimbra (Old Cathedral of Coimbra), which is the only Romanesque cathedral in Portugal to have survived relatively intact since the Reconquista times, scientists retrieved a peculiar slow-growing microcolonial black fungus.

What João Trovão of the University of Coimbra (Portugal) and his colleagues were looking at turned out to be a species of a whole new family (Aeminiaceae) in the order of the sooty mould fungi. The new species, its new genus and the novel family are described in the open-access journal MycoKeys.

New family of fungi threatens a UNESCO-listed 8-century-old cathedral in Portugal
This is the ‘Santa Maria’ chapel (top) and the artwork from which the scientists retrieved
the studied fungi (bottom) [Credit: Miguel Mesquita]

To define the new group of fungi, the researchers first scraped off samples from a deteriorated limestone artwork in the “Santa Maria” chapel and then conducted an extensive and integrative analysis, based on morphological, physiological, ecological characters and DNA sequences.
As for the origin of the previously unknown fungus, the scientists hypothesise that the species had ‘arrived’ at the Old Cathedral of Coimbra with the limestone used during its construction. Coming from the unique nearby areas of Ançã and Portunhos, such limestone has been used on several of the “Our Ladies of the O” statues, as well as in the portal of the Royal Hospital in Santiago de Compostela (Spain). Currently, these fungi are considered endemic to the limestone quarries in the Iberian Peninsula.

“Regarding stone monuments exposed to the environment, microcolonial black fungi are considered one of the main culprits for the phenomenon of stone biodeterioration, being responsible for severe aesthetic, biochemical and biophysical alterations,” comment the scientists.

New family of fungi threatens a UNESCO-listed 8-century-old cathedral in Portugal
This is a colony of the newly described black fungus species Aeminium ludgeri
[Credit: João Trovão]

“It is, therefore, crucial to gather deeper knowledge regarding their biodiversity and their biological, ecological and physiological unique characteristics, in order to span our knowledge regarding these fungi and, at the same time, allow the development and improvement of tools to protect stone monuments from their deteriorative effects.”

Source: Pensoft Publishers [January 29, 2019]



NASA’s NICER Mission Maps ‘Light Echoes’ of New Black Hole

In this illustration of a newly discovered black hole named MAXI J1820+070, a black hole pulls material off a neighboring star and into an accretion disk. Above the disk is a region of subatomic particles called the corona. Credit: Aurore Simonnet and NASA’s Goddard Space Flight Center. Hi-res image

Scientists have charted the environment surrounding a stellar-mass black hole that is 10 times the mass of the Sun using NASA’s Neutron star Interior Composition Explorer (NICER) payload aboard the International Space Station. NICER detected X-ray light from the recently discovered black hole, called MAXI J1820+070 (J1820 for short), as it consumed material from a companion star. Waves of X-rays formed “light echoes” that reflected off the swirling gas near the black hole and revealed changes in the environment’s size and shape.

“NICER has allowed us to measure light echoes closer to a stellar-mass black hole than ever before,” said Erin Kara, an astrophysicist at the University of Maryland, College Park and NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who presented the findings at the 233rd American Astronomical Society meeting in Seattle. “Previously, these light echoes off the inner accretion disk were only seen in supermassive black holes, which are millions to billions of solar masses and undergo changes slowly. Stellar black holes like J1820 have much lower masses and evolve much faster, so we can see changes play out on human time scales.”

A paper describing the findings, led by Kara, appeared in the Jan. 10 issue of Nature and is available online.

J1820 is located about 10,000 light-years away toward the constellation Leo. The companion star in the system was identified in a survey by ESA’s (European Space Agency) Gaia mission, which allowed researchers to estimate its distance. Astronomers were unaware of the black hole’s presence 

until March 11, 2018, when an outburst was spotted by the Japan Aerospace Exploration Agency’s Monitor of All-sky X-ray Image (MAXI), also aboard the space station. J1820 went from a totally unknown black hole to one of the brightest sources in the X-ray sky over a few days. NICER moved quickly to capture this dramatic transition and continues to follow the fading tail of the eruption.

“NICER was designed to be sensitive enough to study faint, incredibly dense objects called neutron stars,” said Zaven Arzoumanian, the NICER science lead at Goddard and a co-author of the paper. “We’re pleased at how useful it’s also proven in studying these very X-ray-bright stellar-mass black holes.”

A black hole can siphon gas from a nearby companion star into a ring of material called an accretion disk. Gravitational and magnetic forces heat the disk to millions of degrees, making it hot enough to produce X-rays at the inner parts of the disk, near the black hole. Outbursts occur when an instability in the disk causes a flood of gas to move inward, toward the black hole, like an avalanche. The causes of disk instabilities are poorly understood.

Above the disk is the corona, a region of subatomic particles around 1 billion degrees Celsius (1.8 billion degrees Fahrenheit) that glows in higher-energy X-rays. Many mysteries remain about the origin and evolution of the corona. Some theories suggest the structure could represent an early form of the high-speed particle jets these types of systems often emit.

Astrophysicists want to better understand how the inner edge of the accretion disk and the corona above it change in size and shape as a black hole accretes material from its companion star. If they can understand how and why these changes occur in stellar-mass black holes over a period of weeks, scientists could shed light on how supermassive black holes evolve over millions of years and how they affect the galaxies in which they reside.

One method used to chart those changes is called X-ray reverberation mapping, which uses X-ray reflections in much the same way sonar uses sound waves to map undersea terrain. Some X-rays from the corona travel straight toward us, while others light up the disk and reflect back at different energies and angles.

X-ray reverberation mapping of supermassive black holes has shown that the inner edge of the accretion disk is very close to the event horizon, the point of no return. The corona is also compact, lying closer to the black hole rather than over much of the accretion disk. Previous observations of X-ray echoes from stellar black holes, however, suggested the inner edge of the accretion disk could be quite distant, up to hundreds of times the size of the event horizon. The stellar-mass J1820, however, behaved more like its supermassive cousins.  

As they examined NICER’s observations of J1820, Kara’s team saw a decrease in the delay, or lag time, between the initial flare of X-rays coming directly from the corona and the flare’s echo off the disk, indicating that the X-rays traveled shorter and shorter distances before they were reflected. From 10,000 light-years away, they estimated that the corona contracted vertically from roughly 100 to 10 miles — that’s like seeing something the size of a blueberry shrink to something the size of a poppy seed at the distance of Pluto.

The NICER instrument installed on the International Space Station, as captured by a high-definition external camera on Oct. 22, 2018. Credits: NASA

“NICER’s observations of J1820 have taught us something new about stellar-mass black holes and about how we might use them as analogs for studying supermassive black holes and their effects on galaxy formation,” said co-author Philip Uttley, an astrophysicist at the University of Amsterdam. “We’ve seen four similar events in NICER’s first year, and it’s remarkable. It feels like we’re on the edge of a huge breakthrough in X-ray astronomy.”

NICER is an Astrophysics Mission of Opportunity within NASA’s Explorer program, which provides frequent flight opportunities for world-class scientific investigations from space utilizing innovative, streamlined and efficient management approaches within the heliophysics and astrophysics science areas. NASA’s Space Technology Mission Directorate supports the SEXTANT component of the mission, demonstrating pulsar-based spacecraft navigation.

“This is the first time that we’ve seen this kind of evidence that it’s the corona shrinking during this particular phase of outburst evolution,” said co-author Jack Steiner, an astrophysicist at the Massachusetts Institute of Technology’s Kavli Institute for Astrophysics and Space Research in Cambridge. “The corona is still pretty mysterious, and we still have a loose understanding of what it is. But we now have evidence that the thing that’s evolving in the system is the structure of the corona itself.”

To confirm the decreased lag time was due to a change in the corona and not the disk, the researchers used a signal called the iron K line created when X-rays from the corona collide with iron atoms in the disk, causing them to fluoresce. Time runs slower in stronger gravitational fields and at higher velocities, as stated in Einstein’s theory of relativity. When the iron atoms closest to the black hole are bombarded by light from the core of the corona, the X-ray wavelengths they emit get stretched because time is moving slower for them than for the observer (in this case, NICER).

Kara’s team discovered that J1820’s stretched iron K line remained constant, which means the inner edge of the disk remained close to the black hole — similar to a supermassive black hole. If the decreased lag time was caused by the inner edge of the disk moving even further inward, then the iron K line would have stretched even more.

These observations give scientists new insights into how material funnels in to the black hole and how energy is released in this process.

By Jeanette Kazmierczak
NASA’s Goddard Space Flight Center, Greenbelt, Md.

Editor: Rob Garner


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