воскресенье, 12 января 2020 г.

In a nearby galaxy, a fast radio burst unravels more questions than answers


For more than a decade, astronomers across the globe have wrestled with the perplexities of fast radio bursts—intense, unexplained cosmic flashes of energy, light years away, that pop for mere milliseconds.

In a nearby galaxy, a fast radio burst unravels more questions than answers
An artist's conception of the localization of Fast Radio Burst 180916.J0158+65 to its host galaxy. The host galaxy image
is based on real observations using the Gemini-North telescope atop Mauna Kea in Hawaii. The impulsive burst
emanating from the galaxy is based on real data recorded using the 100-meter Effelsberg radio telescope
 in Germany [Credit: Danielle Futselaar (artsource.nl)]
Despite the hundreds of records of these enigmatic sources, researchers have only pinpointed the precise location of four such bursts.

Now there's a fifth, detected by a team of international scientists that includes West Virginia University researchers. The finding, which relied on eight telescopes spanning locations from the United Kingdom to China, was published in Nature.


There are two primary types of fast radio bursts, explained Kshitij Aggarwal, a physics graduate student at WVU and a co-author of the paper: repeaters, which flash multiple times, and non-repeaters, one-off events. This observation marks only the second time scientists have determined the location of a repeating fast radio burst.

But the localization of this burst is not quite as important as the type of galaxy it was found in, which is similar to our own, said Sarah Burke-Spolaor, assistant professor of physics and astronomy and co-author.

"Identifying the host galaxy for FRBs is critical to tell us about what kind of environments FRBs live in, and thus what might actually be producing FRBs," Burke-Spolaor said. "This is a question for which scientists are still grasping at straws."

In a nearby galaxy, a fast radio burst unravels more questions than answers
Image of the host galaxy of FRB 180916 (center) acquired with the 8-meter Gemini-North telescope of NSF's OIR Lab
 on Hawaii's Maunakea. Images acquired in SDSS g', r', and z' filters are used for the blue, green, and red colours,
respectively. The position of the FRB in the spiral arm of the galaxy is marked by a green circle [Credit: Gemini
Observatory/NSF’s National Optical-Infrared Astronomy Research Laboratory/AURA]
Burke-Spolaor and her student, Aggarwal, used the Very Large Array observatory in New Mexico to seek pulsations and a persistent radio glow from this burst. Meanwhile, Kevin Bandura, assistant professor of computer science and electrical engineering, and third WVU co-author of the article, worked on the Canadian Hydrogen Intensity Mapping Experiment team that initially detected the repeating fast radio burst.

"What's very interesting about this particular repeating FRB is that it is in the arm of a Milky Way-like spiral galaxy, and is the closest to Earth thus far localized," Bandura said. "The unique proximity and repetition of this FRB might allow for observation in other wavelengths and the potential for more detailed study to understand the nature of this type of FRB."


Using a technique known as Very Long Baseline Interferometry, the team achieved a level of resolution high enough to localize the burst to a region approximately seven light years across—a feat comparable to an individual on Earth being able to distinguish a person on the moon, according to CHIME.

With that level of precision, the researchers could analyze the environment from which the burst emanated through an optical telescope.


What they found has added a new chapter to the mystery surrounding the origins of fast radio bursts. This particular burst existed in a radically different environment from previous studies, as the first repeating burst was discovered in a tiny "dwarf" galaxy that contained metals and formed stars, Burke-Spolaor said.

"That encouraged a lot of publications saying that repeating FRBs are likely produced by magnetars (neutron stars with powerful magnetic fields)," she said. "While that is still possible, the fact that this FRB breaks the uniqueness of that previous mold means that we have to consider perhaps multiple origins or a broader range of theories to understand what creates FRBs."


At half-a-billion light years from Earth, the source of this burst, named "FRB 180916," is seven times closer than the only other repeating burst to have been localized, and more than 10 times closer than any of the few non-repeating bursts scientists have managed to pinpoint. Researchers are hopeful that this latest observation will enable further studies that unravel the possible explanations behind fast radio bursts, according to CHIME.

WVU has remained at the research forefront of fast radio bursts since they were first discovered in 2007 by a team right here at the University that included Duncan Lorimer and Maura McLaughlin, physics professors, and then-student David Narkevic. The trio discovered fast radio bursts from scouring archived data from Australia's Parkes Radio Telescope.

Source: West Virginia University [January 07, 2020]



* This article was originally published here

Geographers find tipping point in deforestation


University of Cincinnati geography researchers have identified a tipping point for deforestation that leads to rapid forest loss.

Geographers find tipping point in deforestation
A University of Cincinnati land-use map shows changing landscapes in North and South America between 1992 and 2015.
White indicates little or no change. Darker shades indicate the highest rate of change in each category. Forest loss
was the most noticeable category in Central and South America [Credit: Tomasz Stepinski/UC]
Geography professor Tomasz Stepinski used high-resolution satellite images from the European Space Agency to study landscapes in 9-kilometer-wide blocks across every inch of the planet between 1992 and 2015. He found that deforestation occurs comparatively slowly in these blocks until about half of the forest is gone. Then the remaining forest disappears very quickly.

Stepinski and former UC postdoctoral researcher Jakub Nowosad, the lead author, discovered something surprising and fundamental: nature abhors mixed landscapes, at least on a scale of 81 square kilometers. The study showed that mixed landscapes (like agriculture and forest) are comparatively few and, more surprisingly, do not stay mixed for long. These mixed blocks tend to become homogeneous over time, regardless of the landscape type.


"I think it's very intuitive. It corresponds to the different climatic zones. The Earth before people was certainly like that. You had forests and mountains and wetlands and deserts," Stepinski said. "You would expect people would create more fragmentation, but as it turns out, people never stop. They convert the entire block on a large scale."

Stepinski said landscapes are always changing through natural or anthropological causes. Human causes are both direct, like clear-cutting, or indirect like climate change.

Last year, Stepinski used the same data to demonstrate that 22% of the Earth's habitable surface was altered in measurable ways between 1992 and 2015. The biggest change: forest to agriculture.

For the new study, Stepinski examined nearly 1.8 million blocks covering Earth's seven continents. Blocks were categorized by 64 landscape combinations. Researchers observed transitions in these blocks from predominantly one type to predominantly another in nearly 15% of the blocks between 1992 and 2015.

Geographers find tipping point in deforestation
A University of Cincinnati land-use map shows changing landscapes in Europe and Asia between 1992 and 2015.
White indicates little or no change. Darker shades indicate the highest rate of change in each category
[Credit: Tomasz Stepinski/UC]
"The data we have covers 23 years. That's a relatively short period of time. But from that we can calculate change in the future," Stepinski said.

Deforestation was the most pronounced example of human-caused landscape change, researchers found. They used probability modeling known as Monte Carlo methods to determine the likelihood of different types of landscape change over time (in this case hundreds of years).

The result? Researchers found that the most likely trajectory of change was from one homogeneous type to another.


"Planet Earth wants to be homogeneous. The land wants to be the same in all these patches. And when they start to change, they don't stop until they convert everything into another homogeneous block," he said.

The authors did not examine why blocks change so quickly once a transition begins. But Stepinski said it's possible that development such as logging roads or drainage required to clear forest makes continued change that much easier.

"I can only speculate because that was not part of the study, but I would imagine two things are happening," he said. "If you are cutting forest, you have the infrastructure to finish it. It's so much easier to cut the rest. Second, the forest is more vulnerable to change when there has been a disturbance."

Geographers find tipping point in deforestation
A University of Cincinnati land-use map shows changing landscapes in Africa and Oceania between 1992 and 2015.
White indicates little or no change. Darker shades indicate the highest rate of change in each category
[Credit: Tomasz Stepinski/UC]
Wildlife managers often try to preserve larger intact blocks to prevent fragmentation, said Martin McCallister, the Appalachian Forest project manager for the Edge of Appalachia Nature Preserve in southern Ohio. The preserve is managed by the Nature Conservancy, one of the world's largest wildlife conservation organizations.

"You'd be hard pressed to find land managers who wouldn't be strongly in favor of protecting larger tracts because they're more resilient to a variety of challenges, including invasive species and climate change," McCallister said. "Once a property gets fragmented by roads, it's easier to extract resources. It's also easier for invasive species and pests to get a foothold."

McCallister said woodlands can be fragmented on paper, too.


"In Ohio, 96 percent of our woodland owners have less than 50 acres. They represent a lot of small parcels," he said.

The UC study found that mixed land types don't stay mixed for long.

"I think it is interesting that this property applies both to natural and human landscapes," said co-author Nowosad, a former UC postdoctoral researcher who now works as an assistant professor at the Adam Mickiewicz University in Poland.

Geographers find tipping point in deforestation
Satellite images show irrigated fields in Texas [Credit: Google Earth]
Nowosad said the study provides a data-driven model of long-term landscape change. While researchers only looked at changes between forest and agriculture, Nowosad said it would be worthwhile to examine whether tipping points exist for other landscape transitions.

"This model can be used to help understand how landscapes evolved and are going to evolve in the future," Nowosad said.

Stepinski, a physicist who worked for NASA before coming to UC, said the principle borrows from other disciplines, particularly astrophysics.


"If you look at the evolution of stars, the principle is you predict a long-term path statistically from short-term knowledge," Stepinski said. "It's an idea that has been used elsewhere but never for environmental study."

While it's only a theory, it's one that could be borne out by time, he said.

"It's thought-provoking. My hope is that people will criticize it and come up with different ideas," Stepinski said.

The study was published in the journal Geophysical Research Letters.

Author: Michael Miller | Source: University of Cincinnati [January 07, 2020]



* This article was originally published here


* This article was originally published here

Research team traces evolution of the domesticated tomato


In a new paper, a team of evolutionary biologists and geneticists led by senior author associate professor Ana Caicedo, with first author Hamid Razifard at the University of Massachusetts Amherst, and others, report that they have identified missing links in the tomato's evolution from a wild blueberry-sized fruit in South America to the larger modern tomato of today.

Research team traces evolution of the domesticated tomato
Evolutionary biologists and geneticists at UMass Amherst report that they have identified missing links in the tomato's
evolution from a wild blueberry-sized fruit in South America to the larger modern tomato of today
[Credit: University of Georgia/Alexis Ramos]
The missing link that deserves more attention than it has gotten to date, they say, is one of a number of intermediate variants between the fully wild and fully domesticated tomato. Results of their genetic studies indicate that the modern cultivated tomato is most closely related to a weed-like tomato group still found in Mexico rather than to semi-domesticated intermediate types found in South America.

Razifard, a postdoctoral researcher in the Caicedo lab, says, "What's new is that we propose that about 7,000 years ago, these weedy tomatoes may have been re-domesticated into the cultivated tomato." The common cultivated tomato is the world's highest value and most widely grown vegetable crop and an important model for studying fruit development, Caicedo and colleagues point out.

In this work, part of a larger research effort supported by the National Science Foundation and led by Esther van der Knaap at the University of Georgia, the researchers say that for many years an oversimplified view of tomato domestication was thought to involve two major transitions, the first from small, wild Solanum pimpinellifolium L. (SP) to a semi-domesticated intermediate, S. lycoperiscum L. var. cerasiforme (SLC). The second was a transition from an intermediate group (SLC) to fully domesticated cultivated tomato (S. lycopersicum L. var. lycopersicum (SLL)).


Their genetic studies address the role of what they call a "historically contentious" and complex intermediate stage of tomato domestication, an essential chapter that should not be overlooked in the tomato's long journey from wildness to domestication. Details appear in Molecular Biology and Evolution.

Razifard and colleagues, who created a public genomic variants dataset for this study, used whole-genome sequencing of wild, intermediate and domesticated (SP, SLC, and SLL) varieties, plus population genomic analyses to reconstruct tomato domestication, focusing on evolutionary changes especially in the intermediate stages (SLC). They generated new whole-genome sequences for 166 samples, with particular attention to intermediate variants from its native range and cultivated fruit from Mexico, previously under-represented in studies.

Razifard says, "We found that SLC may have originated in Ecuador around 80,000 years ago as a wild species rather than a domesticate. It was cultivated in Peru and Ecuador by native people later to create medium-size tomato fruits. We also found that two subgroups from the intermediate group may have spread northward to Central America and Mexico possibly as a weedy companion to other crops."

Research team traces evolution of the domesticated tomato
Tomato domestication history is generally depicted as a "two-step" process with an increase in fruit size from blueberry-
sized SP to generally cherry-sized SLC, and then to the very large-fruited common tomatoes (SLL) consumed around
 the world. All the signs from the study analyses pointed to the intermediate group (SLC) emerging in Ecuador---far
earlier than human domestication--- then spreading out northward over time, suggesting that human use of SLC
came much later. They reconstructed a putative domestication history of tomato groups, focusing especially on
the under-explored intermediate stage represented by SLC. They found that SLC originated in Ecuador probably
as a wild species over 78 KYA, likely as a vicariance event that separated more coastal SP populations from
 inland emerging SLC [Credit: Hamid Razifard, University of Massachusetts, Amherst]
"Remarkably, these northward extensions of SLC seem to have lost some of the domestication-related phenotypes present in South America. They still grow in milpas of Mexico, where people use them as food although not cultivating them intentionally," he adds. Milpas are fields where farmers plant many different crops in the same area.

He and Caicedo note that an origin of the domestic tomato from weed-like ancestors was proposed in 1948 based on the many native names that exist for the weed-like tomato, in contrast to fewer names for the common cultivated tomato. This hypothesis was challenged by others who argued against Mexico as a center of tomato domestication due to the absence of completely wild tomatoes there.

Razifard says, "It's still a mystery how tomatoes have moved northward. All we have is genetic evidence and no archaeological evidence because tomato seeds don't preserve well in the archeological records."


The researchers point out that exploring intermediate stages of tomato domestication has "direct implications for crop improvement." For example, they observed some signals of selection in certain intermediate populations for alleles involved in disease resistance and drought tolerance, important, Razifard says, "Such evidence is useful for finding candidate alleles that can be used for creating disease-resistant and/or drought-tolerant tomatoes." Other intermediate populations had higher beta-carotene or sugar content, attractive traits to consumers.

The evolutionary biologist says, "This is the kind of paper that Darwin would have enjoyed reading. He drew many of his insights on evolution from studying plants, especially crops. He corresponded extensively with botanists before he finalized his theory of evolution through natural selection."

A postdoctoral researcher who did much of the population genomic analyses for this project, Razifard adds that he wants to support the movement in biology against "plant blindness," the tendency to ignore the importance of plants in studying evolution as well as other subfields of biology. Also, he is from a minority Azerbaijani-speaking area of Iran and says, "This paper is special to me because it's my first one with a female-majority author list. I feel lucky to be part of a generation that is changing science, and I hope this paper serves as a model for gender equity in STEM fields."

Source: University of Massachusetts Amherst [January 07, 2020]



* This article was originally published here

2020 January 12 Stars and Dust in Corona Australis Image...



2020 January 12

Stars and Dust in Corona Australis
Image Credit & Copyright: CHART32 Team, Processing - Johannes Schedler

Explanation: Cosmic dust clouds and young, energetic stars inhabit this telescopic vista, less than 500 light-years away toward the northern boundary of Corona Australis, the Southern Crown. The dust clouds effectively block light from more distant background stars in the Milky Way. But the striking complex of reflection nebulae cataloged as NGC 6726, 6727, and IC 4812 produce a characteristic blue color as light from the region’s young hot stars is reflected by the cosmic dust. The dust also obscures from view stars still in the process of formation. At the left, smaller yellowish nebula NGC 6729 bends around young variable star R Coronae Australis. Just below it, glowing arcs and loops shocked by outflows from embedded newborn stars are identified as Herbig-Haro objects. On the sky this field of view spans about 1 degree. That corresponds to almost 9 light-years at the estimated distance of the nearby star forming region.

∞ Source: apod.nasa.gov/apod/ap200112.html



* This article was originally published here

‘Welsh Incident’ Sculpture, Criccieth, North Wales, 5.1.20.

‘Welsh Incident’ Sculpture, Criccieth, North Wales, 5.1.20.



* This article was originally published here

100 million years in amber: Researchers discover oldest fossilized slime mould


Most people associate the idea of creatures trapped in amber with insects or spiders, which are preserved lifelike in fossil tree resin. An international research team of palaeontologists and biologists from the Universities of Gottingen and Helsinki, and the American Museum of Natural History in New York has now discovered the oldest slime mould identified to date. The fossil is about 100 million years old and is exquisitely preserved in amber from Myanmar. The results have been published in the journal Scientific Reports.

100 million years in amber: Researchers discover oldest fossilized slime mould
100 million-year-old amber piece with lizard leg and mycomycete (arrow)
[Credit: Alexander Schmidt, University of Gottingen]
Slime moulds, also called myxomycetes, belong to a group known as 'Amoebozoa'. These are microscopic organisms that live most of the time as single mobile cells hidden in the soil or in rotting wood, where they eat bacteria. However, they can join together to form complex, beautiful and delicate fruiting bodies, which serve to make and spread spores.


Since fossil slime moulds are extremely rare, studying their evolutionary history has been very difficult. So far, there have only been two confirmed reports of fossils of fruiting bodies and these are just 35 to 40 million years old. The discovery of fossil myxomycetes is very unlikely because their fruiting bodies are extremely short-lived. The researchers are therefore astounded by the chain of events that must have led to the preservation of this newly identified fossil.

100 million years in amber: Researchers discover oldest fossilized slime mould
Group of several fruiting bodies of a slime mould (myxomycetes), around 2.5 millimetres
long, in amber, which is about 100 million years old, from Myanmar: long-stalked
 fruiting bodies support the distribution of the spores, then as now
[Credit: Alexander Schmidt, University of Gottingen]
"The fragile fruiting bodies were most likely torn from the tree bark by a lizard, which was also caught in the sticky tree resin, and finally embedded in it together with the reptile," says Professor Jouko Rikkinen from the University of Helsinki. The lizard detached the fruiting bodies at a relatively early stage when the spores had not yet been released, which now reveals valuable information about the evolutionary history of these fascinating organisms.


The researchers were surprised by the discovery that the slime mould can easily be assigned to a genus still living today. "The fossil provides unique insights into the longevity of the ecological adaptations of myxomycetes," explains palaeontologist Professor Alexander Schmidt from the University of Gottingen, lead author of the study.

"We interpret this as evidence of strong environmental selection. It seems that slime moulds that spread very small spores using the wind had an advantage," says Rikkinen. The ability of slime moulds to develop long-lasting resting stages in their life cycle, which can last for years, probably also contributes to the remarkable similarity of the fossil to its closest present-day relatives.

Source: University of Gottingen [January 08, 2020]



* This article was originally published here

Prehistoric Pottery Photoset 2, Oriel Ynys Mon, Llangefni, Anglesey, North Wales, 5.1.20.

Prehistoric Pottery Photoset 2, Oriel Ynys Mon, Llangefni, Anglesey, North Wales, 5.1.20.



* This article was originally published here

Mexico returns 37 archaeological pieces to Peru


The Government of Mexico recently returned 37 archaeological pieces to the Peruvian State, the Mexican Culture Ministry has reported.

Mexico returns 37 archaeological pieces to Peru
Credit: Mauricio Marat, INAH
The objects — from the timeframe between the pre-Columbian era and the viceregal period — were voluntarily handed over or recently confiscated.


According to Mexico's National Institute of Anthropology and History (INAH) Director Diego Prieto, the returned pieces —except for a couple of wooden vessels from the viceregal period— are "outstanding examples" of Nazca, Chimu, Inca, Lambayeque, Recuay, and Chancay Cultures' pottery, metallurgy, and textile industries.

Mexico returns 37 archaeological pieces to Peru
Mexico returns 37 archaeological pieces to Peru
Mexico returns 37 archaeological pieces to Peru
Mexico returns 37 archaeological pieces to Peru
Credit: Mauricio Marat, INAH


Mexico returns 37 archaeological pieces to Peru
Mexico returns 37 archaeological pieces to Peru
Mexico returns 37 archaeological pieces to Peru
Mexico returns 37 archaeological pieces to Peru
Credit: Mauricio Marat, INAH
Within this framework, the restitution of archaeological pieces took place on Tuesday during the III Meeting of the Peru-Mexico Strategic Partnership Agreement Council headed by Mexican Foreign Affairs Minister Marcelo Ebrard and his Peruvian counterpart Gustavo Meza-Cuadra.

"Despite conflagrations that represent a global stability risk, actions such as the restitution of these invaluable pieces are ‘hope glimmers’ that contribute to diplomacy," Minister Ebrard stated.

Source: Andina [January 08, 2020]



* This article was originally published here

New Technique May Give NASA’s Webb Telescope a Way to Quickly Identify Planets with Oxygen

Conceptual image of water-bearing (left) and dry (right) exoplanets with oxygen-rich atmospheres. Crescents are other planets in the system, and the red sphere is the M-dwarf star around which the exoplanets orbit. The dry exoplanet is closer to the star, so the star appears larger. Credits: NASA/GSFC/Friedlander-Griswold

Researchers may have found a way that NASA's James Webb Space Telescope can quickly identify nearby planets that could be promising for our search for life, as well as worlds that are uninhabitable because their oceans have vaporized.

Since planets around other stars (exoplanets) are so far away, scientists cannot look for signs of life by visiting these distant worlds. Instead, they must use a cutting-edge telescope like Webb to see what's inside the atmospheres of exoplanets. One possible indication of life, or biosignature, is the presence of oxygen in an exoplanet’s atmosphere. Oxygen is generated by life on Earth when organisms such as plants, algae and cyanobacteria use photosynthesis to convert sunlight into chemical energy.

But what should Webb look for to determine if a planet has a lot of oxygen? In a new study, researchers identified a strong signal that oxygen molecules produce when they collide. Scientists say Webb has the potential to detect this signal in the atmospheres of exoplanets.

“Before our work, oxygen at similar levels as on Earth was thought to be undetectable with Webb, but we identify a promising way to detect it in nearby planetary systems,” said Thomas Fauchez of the Universities Space Research Association at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This oxygen signal is known since the early 80’s from Earth’s atmospheric studies, but has never been studied for exoplanet research.” Fauchez is the lead author of the study, appearing in the journal Nature Astronomy January 6.

The researchers used a computer model to simulate this oxygen signature by modeling the atmospheric conditions of an exoplanet around an M dwarf, the most common type of star in the universe. M dwarf stars are much smaller, cooler, and fainter than our Sun, yet much more active, with explosive activity that generates intense ultraviolet light. The team modelled the impact of this enhanced radiation on atmospheric chemistry, and used this to simulate how the component colors of the star's light would change when the planet would pass in front of it.

As starlight passes through the exoplanet’s atmosphere, the oxygen absorbs certain colors (wavelengths) of light— in this case, infrared light with a wavelength of 6.4 micrometers. When oxygen molecules collide with each other or with other molecules in the exoplanet’s atmosphere, energy from the collision puts the oxygen molecule in a special state that temporarily allows it to absorb the infrared light. Infrared light is invisible to the human eye, but detectable using instruments attached to telescopes.

“Similar oxygen signals exist at 1.06 and 1.27 micrometers and have been discussed in previous studies but these are less strong and much more mitigated by the presence of clouds than the 6.4 micrometer signal,” said Geronimo Villanueva, a co-author of the paper at Goddard.

Intriguingly, oxygen can also make an exoplanet appear to host life when it does not, because it can accumulate in a planet’s atmosphere without any life activity at all. For example, if the exoplanet is too close to its host star or receives too much star light, the atmosphere becomes very warm and saturated with water vapor from evaporating oceans. This water could be then broken down by the strong ultraviolet radiation into atomic hydrogen and oxygen. Hydrogen, which is a light atom, escapes to space very easily, leaving the oxygen behind.

Over time, this process can cause entire oceans to be lost while building up a thick oxygen atmosphere. So, abundant oxygen in an exoplanet’s atmosphere does not necessarily mean abundant life, but may instead indicate a rich water history.

“Depending upon how easily Webb detects this 6.4 micrometer signal, we can get an idea about how likely it is that the planet is habitable,” said Ravi Kopparapu, a co-author of the paper at Goddard. “If Webb points to a planet and detects this 6.4 micrometer signal with relative ease, this would mean that the planet has a very dense oxygen atmosphere and may be uninhabitable.”

The oxygen signal is so strong that it also can tell astronomers whether M dwarf planets have atmospheres at all, using just a few Webb transit observations.

“This is important because M dwarf stars are highly active, and it has been postulated that stellar activity might ‘blow away’ entire planetary atmospheres,” said Fauchez. “Knowing simply whether a planet orbiting an M dwarf can have an atmosphere at all is important for understanding star-planet interactions around these abundant but active stars.”

Although the oxygen signal is strong, cosmic distances are vast and M dwarfs are dim, so these stars will have to be relatively nearby for Webb to detect the signal in exoplanet atmospheres within a reasonable amount of time. An exoplanet with a modern Earth-like atmosphere will have to be orbiting an M dwarf that is within approximately 16 light-years of Earth. For a desiccated exoplanet with an oxygen atmosphere 22 times the pressure of Earth’s, the signal could be detected up to about 82 light-years away. One light-year, the distance light travels in a year, is almost six trillion miles. For comparison, the closest stars to our Sun are found in the Alpha Centauri system a little over 4 light-years away, and our galaxy is about 100,000 light-years across.

The research was funded in part by Goddard’s Sellers Exoplanet Environments Collaboration (SEEC), which is funded in part by the NASA Planetary Science Division's Internal Scientist Funding Model. This project has also received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Grant, the NASA Astrobiology Institute Alternative Earths team, and the NExSS Virtual Planetary Laboratory.

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

Bill Steigerwald / Nancy Jones

NASA Goddard Space Flight Center, Greenbelt, Maryland

301-286-8955 / 301-286-0039

william.a.steigerwald@nasa.gov / nancy.n.jones@nasa.gov

Editor: Bill Steigerwald





* This article was originally published here

Bryn Celli Ddu Rock Outcrop, Anglesey, North Wales, 3.1.20.Its proximity to the famous burial mound...

Bryn Celli Ddu Rock Outcrop, Anglesey, North Wales, 3.1.20.

Its proximity to the famous burial mound mean that the rock outcrop must have been a key location through the prehistoric site’s construction and development. The photos seem to suggest either a smaller cairn, mound or hut circles.



* This article was originally published here

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