Roman Copper Alloy Brooch (1st or 2nd century CE), Oriel Ynys Mon, Llangefni, Anglesey, North Wales,...

Roman Copper Alloy Brooch (1st or 2nd century CE), Oriel Ynys Mon, Llangefni, Anglesey, North Wales, 5.1.20.

* This article was originally published here

Scientists discover key to Iron Age ‘Heslington brain’ preservation

The 2,600-year-old Heslington brain, discovered in 2008 near York in the UK, was probably so well-preserved due to tightly folded brain proteins, finds a new UCL-led study. The brain matter was the only soft tissue that remained in the skull, which dated from around 673-482 BCE.

Credit: Petzold et al, 2020

The new findings, published in Journal of the Royal Society Interface, suggest that the first few months after the person’s death may have been key to the extraordinary degree of brain preservation. In the absence of any experimental evidence it is less likely, but still possible, that a yet unknown disease may have altered the brain proteins prior to death.

"The manner of this individual’s death, or subsequent burial, may have enabled the brain’s long term preservation,” said the study’s lead author Dr Axel Petzold (UCL Queen Square Institute of Neurology).

Credit: Petzold et al, 2020

Dr Petzold was interested in studying this brain as he had spent years pioneering research in two types of filaments in the brain – neurofilaments and glial fibrillary acidic protein (GFAP) – which act like scaffolds to hold brain matter together (much like the scaffold in a historic building), and he suspected that the proteins may have played a key role.

He and his team found that both these filament types were still present in the Heslington brain, suggesting they were involved in keeping the brain matter together.

Credit: Petzold et al, 2020

Typically, brains decompose quite quickly after death in a rapid process of autolysis – enzymes breaking up the tissue. The research team speculates that these enzymes must have been deactivated within three months after this individual’s death 2,600 years ago, as they found in experiments that it takes three months for proteins to fold themselves tightly into aggregates if autolysis does not occur.

Their findings suggest that an acidic fluid could possibly have got into the brain and prevented autolysis, either as part of how the person died, or after his death. The person is suspected to have been struck in the head or neck or hanged, and subsequently decapitated.

Credit: Petzold et al, 2020

Neurofilament proteins are typically found in greater concentrations in inner areas of the brain (white matter), but in the preserved Heslington brain, they found the opposite, with more filaments in the outer areas of the brain (grey matter). The researchers say this suggests that the inhibition of autolysis would have started in the outer parts of the brain, perhaps as an acidic fluid seeped into the brain.

Credit: Petzold et al, 2020

Dr Petzold says that the findings about brain protein folding and unfolding could also have implications to biomedical research. The research team conducted an experiment to see how long it took brain protein aggregates to unfold themselves, and found it took a full year, which could imply that treatments for neurodegenerative diseases (which involve protein aggregates) may also need to consider a more long-term approach to tackling harmful protein aggregates. The unfolding of the Heslington brain proteins still triggered a strong immune response which was used in this study to generate novel antibodies.

Source: University College London [January 08, 2020]



* This article was originally published here

Prehistoric Tool Making Reconstruction, Oriel Ynys Mon, Llangefni, Anglesey, North Wales, 5.1.20.

Prehistoric Tool Making Reconstruction, Oriel Ynys Mon, Llangefni, Anglesey, North Wales, 5.1.20.

* This article was originally published here

Ptolemaic limestone blocks unearthed in Sohag

Five Ptolemaic limestone blocks have been uncovered in a range of various sizes during an excavation project in the Kom Ashqaw village in Sohag. The blocks have since been moved to the recently-discovered Ptolemy IV temple that is located in the same village, according to the head of the Supreme Council of Antiquities Dr. Mostafa Waziri.

Credit: Egypt. Ministry of Antiquities

The blocks were allegedly part of a shrine dedicated to the god Osiris, likely built during the era of Ptolemy I.

The first block is decorated with patterns that, according to Mohamed Abdul Budaiya, head of the central administration of Upper Egypt, appear to be part of a palace's facade.

Credit: Egypt. Ministry of Antiquities

The second block illustrates two scenes showing Ptolemy I making an offering of clothing to Osiris, while the third block shows  Ptolemy I offering a necklace to Osiris while Isis stands behind him. The other blocks appear to show parts of a similar scene, although they are too fragmented to tell for certain.

Source: Cairo Scene [January 08, 2020]



* This article was originally published here

2020 January 11 NGC 602 and Beyond Image Credit: X-ray:...

2020 January 11

NGC 602 and Beyond
Image Credit: X-ray: Chandra: NASA/CXC/Univ.Potsdam/L.Oskinova et al;
Optical: Hubble: NASA/STScI; Infrared: Spitzer: NASA/JPL-Caltech

Explanation: Near the outskirts of the Small Magellanic Cloud, a satellite galaxy some 200 thousand light-years distant, lies 5 million year young star cluster NGC 602. Surrounded by natal gas and dust, NGC 602 is featured in this stunning Hubble image of the region, augmented by images in the X-ray by Chandra, and in the infrared by Spitzer. Fantastic ridges and swept back shapes strongly suggest that energetic radiation and shock waves from NGC 602’s massive young stars have eroded the dusty material and triggered a progression of star formation moving away from the cluster’s center. At the estimated distance of the Small Magellanic Cloud, the Picture spans about 200 light-years, but a tantalizing assortment of background galaxies are also visible in this sharp multi-colored view. The background galaxies are hundreds of millions of light-years or more beyond NGC 602.

∞ Source: apod.nasa.gov/apod/ap200111.html

* This article was originally published here

Trefllys Ancient Standing Stone, Pentrefelin, North Wales, 5.1.20.

Trefllys Ancient Standing Stone, Pentrefelin, North Wales, 5.1.20.

* This article was originally published here

Climate change threatens Afghanistan's crumbling heritage

After bearing the brunt of jihadist dynamite and looting by thieves, the archaeological treasures of Afghanistan’s Bamiyan province are facing a new and possibly more daunting threat: climate change.

After bearing the brunt of jihadist dynamite and looting by thieves, the archaeological treasures of Afghanistan's
Bamiyan province are facing a new and possibly more daunting threat: climate change [Credit: AFP]

Nestled in the heart of the Hindu Kush mountains, the Bamiyan valley's picturesque cliffs -- where centuries-old Buddha statues were destroyed by the Taliban in 2001 -- still contain a network of caves housing temples, monasteries, and Buddhist paintings.

The valley is also home to the silk-road era Shahr-e Gholghola fortress and the Shar-e Zohak citadel to the east.

Experts say that a pattern of dry spells followed by heavy rain, and larger than usual spring snowmelts is putting this historic art and architecture at risk of destruction.

Afghan officials warned in a 2016 United Nations report that the structures "may collapse and suffer from severe erosion"due to conditions directly linked to climate change.

"The erosion processes are much faster, the rains more devastating and the wind erosion stronger, which has an extremely harsh impact on the sites," Philippe Marquis, the director of the French Archaeological Delegation in Afghanistan, told AFP.

Marquis -- who has explored and worked in the region for decades -- explains that Afghanistan "is very fragile geologically, especially as vegetation cover has greatly diminished" due to deforestation.

Experts say that a pattern of dry spells followed by heavy rain, and larger than usual spring snowmelts
is putting historic art and architecture at risk of destruction in Afghanistan [Credit: AFP]

French imaging company Iconem concurred, saying Shar-e Zohak is "very fragile" due to erosion that has increased considerably over the last 30 years.

For Baqe Ghulami, 21, who hails from Saikhand district in northern Bamiyan, climate change has long been a reality residents have had to confront.

"The weather is changing, now summers are warmer and winters colder," he says, while overlooking the empty spaces where the two towering Buddha statues once stood.

Many of the artefacts pre-date the arrival of Islam to the region but despite the fact they come from another religion, the residents who spoke with AFP proudly defended the area's history as their own.

From the empty caves, visitors can see the Cultural Center, which began construction in 2015 but has yet to be completed.

It aims to educate visitors about the urgent need to preserve the area's heritage.

The Global Adaptation Initiative, run by the University of Notre Dame in the US, currently ranks Afghanistan
173 out of the 181 countries it scored in terms of a nation's vulnerability to climate change
and its ability to adapt [Credit: AFP]

"There is no benefit if people just see (the sites) without information," says Ali Reza Mushfiq, 26, director of the Department of Archeology at Bamiyan University, complaining that a dearth of funding has left many in the dark -- including his own students who lack access to books.

The archaeologist readily admits that "erosion is increasing", but believes the real danger comes from "human influence at the site", including looters, who are rampant in Afghanistan.

The Shar-e Gholghola Fortress and other key sites are now guarded to protect against such issues.

The removal of landmines from the area has seen thousands visit in recent years, but the influx of recent visitors has done little to change the reality on the ground.

"We must start training... (the) local people to teach them how not to destroy the site," says Mushfiq, adding that some residents continue to store feed and house livestock in the historic sites.

A stone's throw from the cave of the great Buddha, Ammanullah, 37, says he and his family have moved into one of the caves, building a home inside made of odds and ends with plastic sheets for windows.

Mitigating the impacts of erosion and the effects of climate change would cost billions of dollars in Afghanistan,
but the war-torn country has little ability to shoulder such a burden [Credit: AFP]

He is not alone, many other poor families have sought shelter next to ancient artefacts and structures.

"There are 18 families here… we didn’t have other options," says Ammanullah.

"We would go if we were given a house."

For Marquis, however, the greatest threat does not come from local residents encroaching on the site or from theft.

"Even if it is dramatic, it is much less damaging than the destruction caused by erosion," he said.

Mitigating the impacts of erosion and the effects of climate change would cost billions of dollars in Afghanistan, but the war-torn country has little ability to shoulder such a burden.

The Global Adaptation Initiative, run by the University of Notre Dame in the US, currently ranks Afghanistan 173 out of the 181 countries it scored in terms of a nation's vulnerability to climate change and its ability to adapt.

Author: Pierre Celerier | Source: AFP [January 09, 2020]



* This article was originally published here

NASA Planet Hunter Finds its 1st Earth-size Habitable-zone World

The three planets of the TOI 700 system orbit a small, cool M dwarf star. TOI 700 d is the first Earth-size habitable-zone world discovered by TESS. Credit: NASA's Goddard Space Flight Center.

NASA’s Transiting Exoplanet Survey Satellite (TESS) has discovered its first Earth-size planet in its star’s habitable zone, the range of distances where conditions may be just right to allow the presence of liquid water on the surface. Scientists confirmed the find, called TOI 700 d, using NASA’s Spitzer Space Telescope and have modeled the planet’s potential environments to help inform future observations.

TOI 700 d is one of only a few Earth-size planets discovered in a star's habitable zone so far. Others include several planets in the TRAPPIST-1 system and other worlds discovered by NASA’s Kepler Space Telescope.

“TESS was designed and launched specifically to find Earth-sized planets orbiting nearby stars,” said Paul Hertz, astrophysics division director at NASA Headquarters in Washington. “Planets around nearby stars are easiest to follow-up with larger telescopes in space and on Earth. Discovering TOI 700 d is a key science finding for TESS. Confirming the planet’s size and habitable zone status with Spitzer is another win for Spitzer as it approaches the end of science operations this January."

NASA's Transiting Exoplanet Survey Satellite (TESS) has discovered its first Earth-size planet in its star's habitable zone, the range of distances where conditions may be just right to allow the presence of liquid water on the surface. Scientists confirmed the find, called TOI 700 d, using NASA's Spitzer Space Telescope and have modeled the planet's potential environments to help inform future observations. Credits: NASA's Goddard Space Flight Center. Download this video in HD formats from NASA Goddard's Scientific Visualization Studio

TESS monitors large swaths of the sky, called sectors, for 27 days at a time. This long stare allows the satellite to track changes in stellar brightness caused by an orbiting planet crossing in front of its star from our perspective, an event called a transit.

TOI 700 is a small, cool M dwarf star located just over 100 light-years away in the southern constellation Dorado. It’s roughly 40% of the Sun’s mass and size and about half its surface temperature. The star appears in 11 of the 13 sectors TESS observed during the mission’s first year, and scientists caught multiple transits by its three planets.

The star was originally misclassified in the TESS database as being more similar to our Sun, which meant the planets appeared larger and hotter than they really are. Several researchers, including Alton Spencer, a high school student working with members of the TESS team, identified the error.

“When we corrected the star’s parameters, the sizes of its planets dropped, and we realized the outermost one was about the size of Earth and in the habitable zone,” said Emily Gilbert, a graduate student at the University of Chicago. “Additionally, in 11 months of data we saw no flares from the star, which improves the chances TOI 700 d is habitable and makes it easier to model its atmospheric and surface conditions.”

Gilbert and other researchers presented the findings at the 235th meeting of the American Astronomical Society in Honolulu, and three papers — one of which Gilbert led — have been submitted to scientific journals.

The innermost planet, called TOI 700 b, is almost exactly Earth-size, is probably rocky and completes an orbit every 10 days. The middle planet, TOI 700 c, is 2.6 times larger than Earth — between the sizes of Earth and Neptune — orbits every 16 days and is likely a gas-dominated world. TOI 700 d, the outermost known planet in the system and the only one in the habitable zone, measures 20% larger than Earth, orbits every 37 days and receives from its star 86% of the energy that the Sun provides to Earth. All of the planets are thought to be tidally locked to their star, which means they rotate once per orbit so that one side is constantly bathed in daylight.

A team of scientists led by Joseph Rodriguez, an astronomer at the Center for Astrophysics | Harvard & Smithsonian in Cambridge, Massachusetts, requested follow-up observations with Spitzer to confirm TOI 700 d.

“Given the impact of this discovery — that it is TESS’s first habitable-zone Earth-size planet — we really wanted our understanding of this system to be as concrete as possible,” Rodriguez said. “Spitzer saw TOI 700 d transit exactly when we expected it to. It’s a great addition to the legacy of a mission that helped confirm two of the TRAPPIST-1 planets and identify five more.”

The Spitzer data increased scientists’ confidence that TOI 700 d is a real planet and sharpened their measurements of its orbital period by 56% and its size by 38%. It also ruled out other possible astrophysical  causes of the transit signal, such as the presence of a smaller, dimmer companion star in the system.

Rodriguez and his colleagues also used follow-up observations from a 1-meter ground-based telescope in the global Las Cumbres Observatory network to improve scientists’ confidence in the orbital period and size of TOI 700 c by 30% and 36%, respectively.

Because TOI 700 is bright, nearby, and shows no sign of stellar flares, the system is a prime candidate for precise mass measurements by current ground-based observatories. These measurements could confirm scientists’ estimates that the inner and outer planets are rocky and the middle planet is made of gas.

Future missions may be able to identify whether the planets have atmospheres and, if so, even determine their compositions.

While the exact conditions on TOI 700 d are unknown, scientists can use current information, like the planet’s size and the type of star it orbits, to generate computer models and make predictions. Researchers at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, modeled 20 potential environments of TOI 700 d to gauge if any version would result in surface temperatures and pressures suitable for habitability.

Their 3D climate models examined a variety of surface types and atmospheric compositions typically associated with what scientists regard to be potentially habitable worlds. Because TOI 700 d is tidally locked to its star, the planet’s cloud formations and wind patterns may be strikingly different from Earth’s.

One simulation included an ocean-covered TOI 700 d with a dense, carbon-dioxide-dominated atmosphere similar to what scientists suspect surrounded Mars when it was young. The model atmosphere contains a deep layer of clouds on the star-facing side. Another model depicts TOI 700 d as a cloudless, all-land version of modern Earth, where winds flow away from the night side of the planet and converge on the point directly facing the star.

When starlight passes through a planet’s atmosphere, it interacts with molecules like carbon dioxide and nitrogen to produce distinct signals, called spectral lines. The modeling team, led by Gabrielle Engelmann-Suissa, a Universities Space Research Association visiting research assistant at Goddard, produced simulated spectra for the 20 modeled versions of TOI 700 d.

“Someday, when we have real spectra from TOI 700 d, we can backtrack, match them to the closest simulated spectrum, and then match that to a model,” Engelmann-Suissa said. “It’s exciting because no matter what we find out about the planet, it’s going to look completely different from what we have here on Earth.”

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

The Jet Propulsion Laboratory in Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena. Space operations are based at Lockheed Martin Space in Littleton, Colorado. Data are archived at the Infrared Science Archive housed at IPAC at Caltech. Caltech manages JPL for NASA.

The modeling work was funded through the Sellers Exoplanet Environments Collaboration at Goddard, a multidisciplinary collaboration that brings together experts to build comprehensive and sophisticated computer models to better analyze current and future exoplanet observations.

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

Editor: Rob Garner

Source: NASA/TESS

---

* This article was originally published here

Ty-Mawr Prehistoric Standing Stone, Holy Island, Anglesey, North Wales, 5.1.20.

Ty-Mawr Prehistoric Standing Stone, Holy Island, Anglesey, North Wales, 5.1.20.

* This article was originally published here

Scientists use ancient marine fossils to unravel long-standing climate puzzle

Cardiff University scientists have shed new light on the Earth's climate behaviour during the last known period of global warming over 14 million years ago.

Marine microfossil, foraminifera [Credit: Cardiff University]

During this period, known as the middle Miocene Climate Optimum, global temperatures were as much as 3 to 4 degrees warmer than today’s average temperatures, similar to estimates for 2100. The position of the continents were similar to today and the seas were flourishing with life.

This period, which occurred between 15 and 17 million years ago, has puzzled geologists for decades as they have tried to explain the initial cause of the global warming and the environmental conditions that existed on Earth afterwards.

It is already known that this period of global warming was accompanied by massive volcanic eruptions which covered most of the modern-day Pacific Northwest in the USA, called the Columbia River flood basalts.

Around the same time a significant oil-rich layer of rock, known as the Monterey Formation, was created along the coastline of California as a result of the burial of carbon-rich marine life.

Up until now scientists have struggled to piece together the puzzle and come up with a viable explanation for the origin of the warmth and the link between the volcanic eruptions and the increased amounts of carbon burial.

Prof Carrie Lear, the senior scientist on the study and based at Cardiff University’s School of Earth and Ocean Sciences, said: “Our planet has been warm before. We can use ancient fossils to help understand how the climate system works during these times.”

In their study, published in the journal Nature Communications, the team used the chemistry of marine fossils taken from long sediment cores from the Pacific, Atlantic and Indian oceans to fingerprint the temperature and carbon levels of the seawater in which the ancient creatures once lived during the middle Miocene Climate Optimum.

Their results showed that the massive volcanic eruptions of the Columbia River flood basalts released CO2 into the atmosphere and triggered a decline in ocean pH. With global temperatures rising as a consequence of this, sea-levels also rose, flooding large areas of the continents. This created the ideal conditions to bury large amounts of carbon from the accumulations of marine organisms in sediments, and to transfer volcanic carbon from the atmosphere to the ocean over tens of thousands of years.

“The elevated marine productivity and carbon burial helped to remove some of the carbon dioxide from the volcanoes and acted as a negative feedback, mitigating some, but not all, of the climatic effects associated with the outpouring of volcanic CO2,” said lead author of the study Dr Sindia Sosdian from Cardiff University’s School of Earth and Ocean Sciences.

Past large episodes of volcanism throughout Earth’s history have been linked to mass extinctions and widespread oxygen depletion in the oceans; however, there was no such occurrence in the middle Miocene Climate Optimum.

Co-author of the study Dr Tali Babila from the School of Ocean and Earth Sciences at the Univesity of Southampton added: “During the Miocene Climatic Optimum the response of the oceans and climate was remarkably similar to other massive volcanic eruptions in the geological record. The presence of the Antarctic ice sheet and the relatively slow release of carbon however minimised the magnitude of environmental change and the associated consequences on marine life during this event.”

“Thanks to our findings we now have a very clear picture of what was going on over 14 million years ago and this will change the way that scientists look at this period of global warming,” continued Dr Sosdian.

“We know that our current climate is warming much faster than the Miocene Climatic Optimum so we won’t be able to rely on these slow natural feedbacks to counteract global warming. But this research is still important because it helps us understand how our planet works when it is in a warm mode.”

Source: Cardiff University [January 09, 2020]



* This article was originally published here

Iron Age Hendy Celtic Stone Head, Anglesey, North Wales, 5.1.20.

Iron Age Hendy Celtic Stone Head, Anglesey, North Wales, 5.1.20.

* This article was originally published here

Cosmic bubbles reveal the first stars

Astronomers using the Mayall telescope at Kitt Peak National Observatory, a program of NSF's National Optical-Infrared Astronomy Research Laboratory, have identified several overlapping bubbles of hydrogen gas ionized by the stars in early galaxies, a mere 680 million years after the Big Bang. This is the earliest direct evidence from the period when the first generation of stars formed and began reionizing the hydrogen gas that permeated the Universe.

This rendition shows ionized bubbles formed by three galaxies in galaxy cluster EGS77 [Credit: V. Tilvi et al./
National Science Foundation’s Optical-Infrared Astronomy Research Laboratory/KPNO/AURA]

There was a period in the very early Universe -- known as the "cosmic dark ages" -- when elementary particles, formed in the Big Bang, had combined to form neutral hydrogen but no stars or galaxies existed yet to light up the Universe. This period began less than half a million years after the Big Bang and ended with the formation of the first stars. While this stage in the evolution of our Universe is indicated by computer simulations, direct evidence is sparse.

Now, astronomers using the infrared imager NEWFIRM on the 4-meter Mayall Telescope at the Kitt Peak National Observatory of NSF's National Optical-Infrared Astronomy Research Laboratory (OIR Lab), have reported imaging a group of galaxies, known as EGS77, that contains these first stars. Their results were announced at a press conference held today at the 235th meeting of the American Astronomical Society (AAS) in Honolulu, Hawai'i.

"The young Universe was filled with hydrogen atoms, which so attenuate ultraviolet light that they block our view of early galaxies," said James Rhoads at NASA's Goddard Space Flight Center in Greenbelt, Maryland, who presented the findings at the AAS press conference. "EGS77 is the first galaxy group caught in the act of clearing out this cosmic fog."

The team began with an imaging survey designed to detect high redshift galaxies and combined these data with corresponding images taken by the Hubble Space Telescope. This enabled the team to compute what is known as a photometric redshift, a proxy for estimating distance. At these redshifts, a galaxy's light is shifted completely out of the range of wavelengths to which the human eye is sensitive (the visible spectrum) to longer (infrared) wavelengths. The criteria for selecting distant galaxy candidates included a clear detection of them in the special infrared narrowband filters used with NEWFIRM on the Mayall 4-meter telescope and a complete non-detection in the shorter wavelength optical filter bands used by Hubble. "The discovery of the two fainter galaxies in the group was only possible because of the special narrowband filter used with NEWFIRM," said team leader Vithal Tilvi, a researcher at Arizona State University in Tempe.

"Intense light from galaxies can ionize the surrounding hydrogen gas, forming bubbles that allow starlight to travel freely," said Tilvi. "EGS77 has formed a large bubble that allows its light to travel to Earth without much attenuation. Eventually, bubbles like these grew around all galaxies and filled intergalactic space, clearing the way for light to travel across the Universe."

EGS77 was discovered as part of the Cosmic Deep And Wide Narrowband (Cosmic DAWN) survey, for which Rhoads serves as principal investigator. The team imaged a small area in the constellation of Bootes using a custom-built filter on the National Optical Astronomy Observatory's Extremely Wide-Field InfraRed imager (NEWFIRM). Ron Probst, a DAWN team member who also helped to develop NEWFIRM, adds, "These results show the value of maintaining instruments at our national observatories that are powerful and can flexibly adapt to pursue new scientific questions, questions that may not have been in mind when an instrument was originally built."

Once identified, the distances and hence the ages of these galaxies were confirmed with spectra taken with the MOSFIRE spectrograph at the Keck I telescope at the W. M. Keck Observatory on Maunakea in Hawai'i. All three galaxies show strong emission lines of hydrogen Lyman alpha at a redshift (z = 7.7), which means we are seeing them at about 680 million years after the Big Bang. The size of the ionized bubble around each was derived from computer modeling. These bubbles overlap spatially, but are large enough (about 2.2 million light-years) that Lyman alpha photons are redshifted before they reach the boundary of the bubble and can thus escape unscathed, allowing astronomers to detect them.

"We expected that reionization bubbles from this era in cosmic history would be rare and hard to find," said Sangeeta Malhotra, a collaborator at NASA GSFC, "so confirmation of this transition is important." This "cosmic dawn", the intermediate state between a neutral and an ionized Universe, is something that has been predicted. Such discoveries are made possible by the availability of powerful astronomical instruments that can probe the Universe in a way unimagined by past generations of astronomers.

Author: Peter Michaud | Source: National Science Foundation [January 07, 2020]



* This article was originally published here

Bryn y Mor Iron Age Stone Head, Anglesey, North Wales, 5.1.20.

Bryn y Mor Iron Age Stone Head, Anglesey, North Wales, 5.1.20.

* This article was originally published here

New map of Milky Way reveals giant wave of stellar nurseries

Astronomers at Harvard University have discovered a monolithic, wave-shaped gaseous structure - the largest ever seen in our galaxy - made up of interconnected stellar nurseries. Dubbed the "Radcliffe wave" in honor of the collaboration's home base, the Radcliffe Institute for Advanced Study, the discovery transforms a 150-year-old vision of nearby stellar nurseries as an expanding ring into one featuring an undulating, star-forming filament that reaches trillions of miles above and below the galactic disk.

Visualization of the Radcliffe Wave: a massive, wave-shaped gaseous structure made up of stellar nurseries, forming one
 of the largest coherent structures ever observed in our galaxy. This image, taken from the World Wide Telescope,
represents the study data overlaid on an artist's illustration of the Milky Way and our sun
[Credit: Alyssa Goodman/Harvard University]

The work, published in Nature, was enabled by a new analysis of data from the European Space Agency's Gaia spacecraft, launched in 2013 with the mission of precisely measuring the position, distance, and motion of the stars. The research team combined the super-accurate data from Gaia with other measurements to construct a detailed, 3D map of interstellar matter in the Milky Way, and noticed an unexpected pattern in the spiral arm closest to the Earth.

The researchers discovered a long, thin structure, about 9,000 light years long and 400 light years wide, with a wave-like shape, cresting 500 light years above and below the mid-plane of our Galaxy's disk. The Wave includes many of the stellar nurseries that were previously thought to form part of "Gould's Belt", a band of star-forming regions believed to be oriented around the Sun in a ring.

"No astronomer expected that we live next to a giant, wave-like collection of gas - or that it forms the Local Arm of the Milky Way," said Alyssa Goodman, the Robert Wheeler Willson Professor of Applied Astronomy at Harvard University, research associate at the Smithsonian Institution, and co-director of the Science Program at the Radcliffe Institute of Advanced Study. "We were completely shocked when we first realized how long and straight the Radcliffe Wave is, looking down on it from above in 3D - but how sinusoidal it is when viewed from Earth. The Wave's very existence is forcing us to rethink our understanding of the Milky Way's 3D structure."

"Gould and Herschel both observed bright stars forming in an arc projected on the sky, so for a long time, people have been trying to figure out if these molecular clouds actually form a ring in 3D," said Joao Alves, professor of stellar astrophysics at the University of Vienna and Radcliffe Fellow (2018-2019). "Instead, what we've observed is the largest coherent gas structure we know of in the galaxy, organized not in a ring but in a massive, undulating filament. The Sun lies only 500 light years from the Wave at its closest point. It's been right in front of our eyes all the time, but we couldn't see it until now."

The new, 3D map shows our galactic neighborhood in a new light, giving researchers a revised view of the Milky Way and opening the door to other major discoveries.

"We don't know what causes this shape but it could be like a ripple in a pond, as if something extraordinarily massive landed in our galaxy," said Alves. "What we do know is that our Sun interacts with this structure. It passed by a festival of supernovae as it crossed Orion 13 million years ago, and in another 13 million years it will cross the structure again, sort of like we are 'surfing the wave'."

An insider's view of the galaxy

Disentangling structures in the "dusty" galactic neighborhood within which we sit is a long-standing challenge in astronomy. In earlier studies, the research group of Douglas Finkbeiner, professor of astronomy and physics at Harvard, pioneered advanced statistical techniques to map the 3D distribution of dust using vast surveys of stars' colors. Armed with new data from Gaia, Harvard graduate students Catherine Zucker and Joshua Speagle recently augmented these techniques, dramatically improving the ability of astronomers to measure distances to star-forming regions. That work, led by Zucker, is published in the Astrophysical Journal.

"We suspected there might be larger structures that we just couldn't put in context. So, to create an accurate map of our solar neighborhood, we combined observations from space telescopes like Gaia with astrostatistics, data visualization, and numerical simulations." explained Zucker, who is an NSF Graduate Fellow and Ph.D. candidate at Harvard's Graduate School of Arts and Sciences based in Harvard's department of Astronomy.

Zucker played a key role in compiling the largest-ever catalog of accurate distances to local stellar nurseries - the basis for the 3D map used in the study. She has set herself the goal of painting a new picture of the Milky Way Galaxy, near and far. "We pulled this team together so we could go beyond processing and tabulating the data to actively visualizing it - not just for ourselves but for everyone. Now, we can literally see the Milky Way with new eyes," she said.

"Studying stellar births is complicated by imperfect data. We risk getting the details wrong, because if you're confused about distance, you're confused about size." said Finkbeiner.

Goodman agreed, "All of the stars in the universe, including our Sun, are formed in dynamic, collapsing, clouds of gas and dust. But determining how much mass the clouds have, how large they are - has been difficult, because these properties depend on how far away the cloud is."

A universe of data

According to Goodman, scientists have been studying dense clouds of gas and dust between the stars for over a hundred years, zooming in on these regions with ever-higher resolution. Before Gaia, there were no significant datasets expansive enough to reveal the galaxy's structure on large scales. Since its launch in 2013, the space observatory has enabled measurements of the distances to one billion stars in the Milky Way galaxy.

The flood of data from Gaia served as the perfect testbed for innovative, new statistical methods that reveal the shape of local stellar nurseries and their connection to the Milky Way's galactic structure. In this data-science-oriented collaboration, the Finkbeiner, Alves, and Goodman groups collaborated closely. The Finkbeiner group developed the statistical framework needed to infer the 3D distribution of the dust clouds; the Alves group contributed deep expertise on stars, star formation, and Gaia; and the Goodman group developed the 3D visualizations and analytic framework, called "glue", that allowed the Radcliffe Wave to be seen, explored, and quantitatively described.

Author: Mary Todd Bergman | Source: Harvard University [January 07, 2020]



* This article was originally published here

Replica Iron Age Gang Chain for Slaves or Captives from Llyn Cerrig Bach, Oriel Ynys Mon, Anglesey,...

Replica Iron Age Gang Chain for Slaves or Captives from Llyn Cerrig Bach, Oriel Ynys Mon, Anglesey, North Wales, 5.1.20.

* This article was originally published here

The Milky Way's impending galactic collision is already birthing new stars

The outskirts of the Milky Way are home to the galaxy's oldest stars. But astronomers have spotted something unexpected in this celestial retirement community: a flock of young stars.

A newfound cluster of young stars (blue star) sits on the periphery of the Milky Way. These stars probably
 formed from material originating from neighboring dwarf galaxies called the Magellanic Clouds
[Credit: D. Nidever; NASA]

More surprising still, spectral analysis suggests that the infant stars have an extragalactic origin. The stars seemingly formed not from material from the Milky Way, but from two nearby dwarf galaxies known as the Magellanic Clouds. Those galaxies are on a collision course with our own. The discovery suggests that a stream of gas extending from the galaxies is about half as far from crashing into the Milky Way as previously thought.

"This is a puny cluster of stars -- less than a few thousand in total -- but it has big implications beyond its local area of the Milky Way," says primary discoverer Adrian Price-Whelan, a research fellow at the Flatiron Institute's Center for Computational Astrophysics in New York City. (The cluster also bears his name: Price-Whelan 1.)

The newfound stars could reveal new insights into the Milky Way's history; they might, for example, tell if the Magellanic Clouds collided with our galaxy in the past.

Price-Whelan and his colleagues present their findings January 8 at the American Astronomical Society meeting in Honolulu. They previously reported the discovery of Price-Whelan 1 on December 5 in The Astrophysical Journal and their subsequent spectroscopic analysis of the stars on December 16, also in The Astrophysical Journal.

Astronomers have spotted a group of young stars (blue) on the outskirts of the Milky Way. The scientists propose
 that these stars formed from material from two dwarf galaxies known as the Magellanic Clouds
[Credit: A. Price-Whelan]

Identifying clusters of stars is tricky because our galaxy is chock-full of the radiant orbs. Some stars may appear to be close together in the sky but actually sit at drastically different distances from Earth. Other stars may temporarily neighbor one another but move on in opposite directions. Determining which stars are actually clustered together requires many precise measurements over time.

Price-Whelan started with the latest data collected by the Gaia spacecraft, which has measured and cataloged the distances and motions of 1.7 billion stars. He searched the Gaia dataset for very blue stars, which are rare in the universe, and identified clumps of stars moving alongside them. After cross-matching with and removing known clusters, one remained.

The newfound cluster is relatively young at 117 million years old and is on the far outskirts of the Milky Way. "It's really, really far away," Price-Whelan says. "It's further than any known young stars in the Milky Way, which are typically in the disk. So right away, I was like, 'Holy smokes, what is this?'"

The cluster inhabits a region near a river of gas, dubbed the Magellanic Stream, that forms the outmost edge of the Large and Small Magellanic Clouds and reaches toward the Milky Way. Gas in the stream doesn't contain much metal, unlike gases in the outer reaches of the Milky Way. David Nidever, assistant professor of physics at Montana State University in Bozeman, led an analysis of the metal content of the 27 brightest stars in the cluster. Just like the Magellanic Stream, the stars contain meager levels of metal.

Комментариев нет:

NASA's TESS mission uncovers its first world with two stars

In 2019, when Wolf Cukier finished his junior year at Scarsdale High School in New York, he joined NASA's Goddard Space Flight Center in Greenbelt, Maryland, as a summer intern. His job was to examine variations in star brightness captured by NASA's Transiting Exoplanet Survey Satellite (TESS) and uploaded to the Planet Hunters TESS citizen science project.

TOI 1338 b is silhouetted by its host stars. TESS only detects transits from the larger star
[Credit: NASA's Goddard Space Flight Center/Chris Smith]

"I was looking through the data for everything the volunteers had flagged as an eclipsing binary, a system where two stars circle around each other and from our view eclipse each other every orbit," Cukier said. "About three days into my internship, I saw a signal from a system called TOI 1338. At first I thought it was a stellar eclipse, but the timing was wrong. It turned out to be a planet."

TOI 1338 b, as it is now called, is TESS's first circumbinary planet, a world orbiting two stars. The discovery was featured in a panel discussion on Monday, Jan. 6, at the 235th American Astronomical Society meeting in Honolulu. A paper, which Cukier co-authored along with scientists from Goddard, San Diego State University, the University of Chicago and other institutions, has been submitted to a scientific journal.

The TOI 1338 system lies 1,300 light-years away in the constellation Pictor. The two stars orbit each other every 15 days. One is about 10% more massive than our Sun, while the other is cooler, dimmer and only one-third the Sun's mass.

TOI 1338 b is the only known planet in the system. It's around 6.9 times larger than Earth, or between the sizes of Neptune and Saturn. The planet orbits in almost exactly the same plane as the stars, so it experiences regular stellar eclipses.

TESS has four cameras, which each take a full-frame image of a patch of the sky every 30 minutes for 27 days. Scientists use the observations to generate graphs of how the brightness of stars change over time. When a planet crosses in front of its star from our perspective, an event called a transit, its passage causes a distinct dip in the star's brightness.

But planets orbiting two stars are more difficult to detect than those orbiting one. TOI 1338 b's transits are irregular, between every 93 and 95 days, and vary in depth and duration thanks to the orbital motion of its stars. TESS only sees the transits crossing the larger star; the transits of the smaller star are too faint to detect.

"These are the types of signals that algorithms really struggle with," said lead author Veselin Kostov, a research scientist at the SETI Institute and Goddard. "The human eye is extremely good at finding patterns in data, especially non-periodic patterns like those we see in transits from these systems."

Researchers working with data from NASA’s Transiting Exoplanet Survey Satellite (TESS) have discovered the mission’s first 

circumbinary planet, a world orbiting two stars. The planet, called TOI 1338 b, is around 6.9 times larger than Earth,

 or between the sizes of Neptune and Saturn. It lies in a system 1,300 light-years away in the constellation Pictor. The stars

 in the system make an eclipsing binary, which occurs when the stellar companions circle each other in our plane of view. 

One is about 10% more massive than our Sun, while the other is cooler, dimmer and only one-third the Sun’s mass. 

TOI 1338 b’s transits are irregular, between every 93 and 95 days, and vary in depth and duration thanks to the orbital

 motion of its stars. TESS only sees the transits crossing the larger star — the transits of the smaller star are too faint

 to detect. Its orbit is stable for at least the next 10 million years. The orbit’s angle to us, however, changes enough 

that the planet transit will cease after November 2023 and resume eight years later 

[Credit: NASA's Goddard Space Flight Center]

This explains why Cukier had to visually examine each potential transit. For example, he initially thought TOI 1338 b's transit was a result of the smaller star in the system passing in front of the larger one -- both cause similar dips in brightness. But the timing was wrong for an eclipse.

After identifying TOI 1338 b, the research team used a software package called eleanor, named after Eleanor Arroway, the central character in Carl Sagan's novel "Contact," to confirm the transits were real and not a result of instrumental artifacts.

"Throughout all of its images, TESS is monitoring millions of stars," said co-author Adina Feinstein, a graduate student at the University of Chicago. "That's why our team created eleanor. It's an accessible way to download, analyze and visualize transit data. We designed it with planets in mind, but other members of the community use it to study stars, asteroids and even galaxies."

TOI 1338 had already been studied from the ground by radial velocity surveys, which measure motion along our line of sight. Kostov's team used this archival data to analyze the system and confirm the planet. Its orbit is stable for at least the next 10 million years. The orbit's angle to us, however, changes enough that the planet transit will cease after November 2023 and resume eight years later.

NASA's Kepler and K2 missions previously discovered 12 circumbinary planets in 10 systems, all similar to TOI 1338 b. Observations of binary systems are biased toward finding larger planets, Kostov said. Transits of smaller bodies don't have as big an effect on the stars' brightness. TESS is expected to observe hundreds of thousands of eclipsing binaries during its initial two-year mission, so many more of these circumbinary planets should be waiting for discovery.

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

Author: Jeanette Kazmierczak | Source: NASA/Goddard Space Flight Center [January 07, 2020]



* This article was originally published here