вторник, 7 января 2020 г.

New study estimates the global extent of river ice loss as Earth warms


More than half of Earth's rivers freeze over every year. These frozen rivers support important transportation networks for communities and industries located at high latitudes. Ice cover also regulates the amount of greenhouse gasses released from rivers into Earth's atmosphere.

New study estimates the global extent of river ice loss as Earth warms
Ice cover on the Yukon River approaching its confluence with the Tanana River in Alaska
[Credit: Landsat imagery/NASA Goddard Space Flight Center
& U.S. Geological Survey]
A new study from researchers in the University of North Carolina at Chapel Hill Department of Geological Sciences found that annual river ice cover will decline by about six days for every one degree Celsius increase in global temperatures. This decline will have economic and environmental consequences. The study, published in the journal Nature, is the first study to look at the future of river ice on a global scale.


"We used more than 400,000 satellite images taken over 34 years to measure which rivers seasonally freeze over worldwide, which is about 56% of all large rivers," said Xiao Yang, a postdoctoral scholar in the UNC-Chapel Hill geological sciences department and lead author on the paper. "We detected widespread declines in monthly river ice coverage. And the predicted trend of future ice loss is likely to lead to economic challenges for people and industries along these rivers, and shifting seasonal patterns in greenhouse gas emissions from the ice-affected rivers."

The team also looked at changes to river ice cover in the past and modeled predicted changes for the future. Comparing river ice cover from 2008-2018 and 1984-1994, the team found a monthly global decline ranging from .3 to 4.3 percentage points. The greatest declines were found in the Tibetan Plateau, eastern Europe and Alaska.


"The observed decline in river ice is likely to continue with predicted global warming," the study explains.

For the future, the team compared expected river ice cover through 2009-2029 and 2080-2100. Findings showed monthly declines in the Northern Hemisphere ranging from 9-15% in the winter months and 12-68% during the spring and fall. The Rocky Mountains, northeastern United States, eastern Europe and Tibetan Plateau are expected to take the heaviest impact.

"Ultimately, what this study shows is the power of combining massive amounts of satellite imagery with climate models to help better project how our planet will change," said UNC-Chapel Hill Associate Professor of global hydrology Tamlin Pavelsky.

Source: University of North Carolina at Chapel Hill [January 01, 2020]



* This article was originally published here

Amateur Astronomer catches UFOs?

78020 views   119 likes   17 dislikes  

Channel: Terry's Theories  

Youtube channel M S makes a great catch as he views and records the moon through his telescope.
Source video : https://www.youtube.com/watch?v=i5JwK0jA1GI

Video length: 1:14
Category: Science & Technology
65 comments

Gigantic ring of hydrogen gas discovered around a distant galaxy


A team of astronomers at the National Centre for Radio Astrophysics (NCRA) in Pune, India have discovered a mysterious ring of hydrogen gas around a distant galaxy, using the Giant Metrewave Radio Telescope (GMRT). The ring is much bigger than the galaxy it surrounds and has a diameter of about 380,000 light-years (about 4 times that of our Milky Way).

Gigantic ring of hydrogen gas discovered around a distant galaxy
The optical image from the CFHT telescope with the distribution of neutral hydrogen in the form of a large
 ring shown in red as observed by the GMRT. The other two red blobs show the distribution
of neutral hydrogen around two other galaxies which are in the vicinity of the ring
[Credit: O. Bait (NCRA-TIFR/GMRT), Duc (ObAS/CFHT)]
The galaxy (named AGC 203001), is located about 260 million light-years away from us. There is only one other such known system with such a large neutral hydrogen ring. The origin and formation of such rings is still a matter of debate among astrophysicists.

Neutral hydrogen emits radio waves at a wavelength of about 21cm. This radiation from neutral hydrogen atoms has allowed radio astronomers to map the amount and distribution of neutral hydrogen gas in our Milky Way galaxy and in other galaxies in the Universe. Typically, large reservoirs of neutral hydrogen gas are found in galaxies which are actively forming new stars.


However, despite showing no signs of active star formation the galaxy AGC 203001 was known to have large amounts of hydrogen, although its exact distribution was not known. The unusual nature of this galaxy motivated astronomers in NCRA to use the GMRT to conduct high-resolution radio observation of this galaxy to find out where in the galaxy this gas lies.

The GMRT observations revealed that the neutral hydrogen is distributed in the form of a large off-centered ring extending much beyond the optical extent of this galaxy. More puzzlingly, the astronomers found that the existing optical images of the ring showed no sign of it containing stars. In collaboration with two French astronomers, Pierre-Alain Duc and Jean-Charles Cuillandre, the NCRA team obtained a very sensitive optical image of this system using the Canada-France-Hawaii-Telescope (CFHT) in Hawaii, USA. However, even these images do not show any sign of starlight associated with the hydrogen ring.


There is no clear answer today as to what could lead to the formation of such large, starless rings of hydrogen. Conventionally, galaxy-galaxy collisions were thought to lead to the formation of such off-centered rings around galaxies. However, such rings also generally contain stars. This is contrary to what is found in this ring. Figuring out how this ring was formed remains a challenge to astronomers.

Encouraged by this discovery, the team is now conducting a large survey to map the neutral hydrogen around several more similar galaxies. If some of them also show rings like this, it should help us to better understand the formation mechanism behind such rare rings.

The discovery is published in the Monthly Notices of the Royal Astronomical Society.

Source: Tata Institute of Fundamental Research [January 02, 2020]



* This article was originally published here

Unknown Craft Descends From Lighting Storm

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Channel: Terry's Theories  

This video shows a unknown craft descending from out of a lighting storm in Argentina on Oct. 28 2019. Recorded by Jessica Bonasola as she was leaving the lake due to bad weather. She decided she wanted to catch some lightning strikes in slow motion on her dash cam and unknowingly caught an amazing capture of a UFO descending from a lighting storm.

Source video : https://www.youtube.com/watch?v=hvjEgfmo4zM

Video length: 2:12
Category: Science & Technology
27 comments

Mynydd y Graig Ancient Hill Fort, Llyn Peninsula, North Wales, 5.1.20.Probably an Iron Age Fort,...

Mynydd y Graig Ancient Hill Fort, Llyn Peninsula, North Wales, 5.1.20.

Probably an Iron Age Fort, this site continued as a site of political importance into the following centuries. Defended on two sides by a natural rocky promontory, all that remains is a rubble rampart and potential areas where hut circles may have existed. The site offers strategic views of the coast from the headland.



* This article was originally published here

Climate change and deforestation could decimate Madagascar's rainforest habitat by 2070


A study in Nature Climate Change has found that, left unchecked, the combined effects of deforestation and human-induced climate change could eliminate Madagascar's entire eastern rainforest habitat by 2070, impacting thousands of plants, mammals, reptiles, and amphibians that are endemic to the island nation. However, the study's authors also found that protected areas will help to mitigate this devastation while environmentalists work toward long-term solutions for ending runaway greenhouse gas emissions and resulting climate change.

Climate change and deforestation could decimate Madagascar's rainforest habitat by 2070
Ruffed lemurs are a keystone species whose survival is critical to the health and continuation of Madagascar’s
eastern rainforest. A new study suggests strict anti-deforestation laws may be most immediately
crucial to their and other species’ survival [Credit: Rabe Franck]
Madagascar - a biodiversity hotspot where 80 to 90% of its animal and plant species are exclusive to the area - has been devasted by decades of deforestation and overharvesting. The activities have destroyed much of the land cover that provides habitat for a variety of unique animals, including currently endangered varieties of lemurs. In particular, two species of ruffed lemurs are now critically endangered, and these animals play a central role in dispersing the seeds of a number of plant species that provide food and shelter for other animals across the rainforest.


"Because of their essential role as seed dispersers and their sensitivity to habitat degradation, ruffed lemurs serve as a critical indicator of the health of Madagascar's entire eastern rainforest," said Andrea Baden, a professor of anthropology at The Graduate Center, CUNY and Hunter College and the study's primary investigator. "When we projected the impact of deforestation and climate change, we found that deforestation alone and climate change alone could reduce ruffed lemur habitat by over 50%. Even more alarming, these two factors together are projected to essentially decimate suitable rainforest habitat by the end of the century."


The researchers' data suggest that the speed and intensity of destruction to Madagascar's eastern rainforest will be greatly determined by whether the country institutes strict protections against deforestation or a relaxed set of policies. Protecting forested areas that provide shelter to ruffed lemurs and serve as corridor links to their strongholds is particularly important to survival given their role as a keystone species that enables the survival of a large number of animal and plant species in one of the world's most biodiverse regions.

"The results from our study will be useful to nonprofit organizations, park management, and the broader conservation community," Baden said. "Our results indicate potential conservation opportunities for ruffed lemurs and any of the rainforest-dwellers that rely on forest cover and connectivity. Protected areas are vital to species persistence."

Source: The Graduate Center, CUNY [January 02, 2020]



* This article was originally published here

Strange Things Are happening.

353 views   51 likes   1 dislikes  

Channel: Terry's Theories  

Two videos, First video takes place on Dec. 8 2019 and recorded by DJ & Kerri in Mesa Arizona. The video shows a strange orange sphere with what looks like fire dripping from it.
Source video : https://www.youtube.com/watch?v=V-xCdiw6xU0&lc=z22nhb3zxtz2hfovgacdp4340z2ltluc01hojeid54dw03c010c.1576780619118661
Second video takes place in Iowa and was rerorded by Youtube channel
Justin Southwick shows what could be the sun shining through the clouds in a strange fashion or maybe not.
Source video : https://www.youtube.com/watch?v=H-3Ql1MYSVk

Video length: 7:17
Category: Science & Technology
29 comments

Mynydd y Graig Ancient Hill Fort, Llyn Peninsula, North Wales, 5.1.20.

Mynydd y Graig Ancient Hill Fort, Llyn Peninsula, North Wales, 5.1.20.



* This article was originally published here

Scientists find evidence that Venus has active volcanoes


New research led by Universities Space Research Association (USRA) and published in Science Advances shows that lava flows on Venus may be only a few years old, suggesting that Venus could be volcanically active today—making it the only planet in our solar system, other than Earth, with recent eruptions.

Scientists find evidence that Venus has active volcanoes
This figure shows the volcanic peak Idunn Mons (at 46 degrees south latitude, 214.5 degrees east longitude)
in the Imdr Regio area of Venus. The colored overlay shows the heat patterns derived from surface
brightness data collected by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS),
aboard the European Space Agency's Venus Express spacecraft [Credit: NASA]
"If Venus is indeed active today, it would make a great place to visit to better understand the interiors of planets," says Dr. Justin Filiberto, the study's lead author and a Universities Space Research Association (USRA) staff scientist at the Lunar and Planetary Institute (LPI). "For example, we could study how planets cool and why the Earth and Venus have active volcanism, but Mars does not. Future missions should be able to see these flows and changes in the surface and provide concrete evidence of its activity."


Radar imaging from NASA's Magellan spacecraft in the early 1990s revealed Venus, our neighboring planet, to be a world of volcanoes and extensive lava flows. In the 2000s, the European Space Agency's (ESA's) Venus Express orbiter shed new light on volcanism on Venus by measuring the amount of infrared light emitted from part of Venus' surface (during its nighttime). These new data allowed scientists to identify fresh versus altered lava flows on the surface of Venus. However, until recently, the ages of lava eruptions and volcanoes on Venus were not well known because the alteratiion rate of fresh lava was not well constrained.


Dr. Filiberto and his colleagues recreated Venus' hot caustic atmosphere in the laboratory to investigate how the observed Venusian minerals react and change over time. Their experimental results showed that an abundant mineral in basalt—olivine—reacts rapidly with the atmosphere and within weeks becomes coated with the iron oxide minerals—magnetite and hematite. They further found that the Venus Express observations of this change in minerology would only take a few years to occur. Thus, the new results by Filiberto and coauthors suggest that these lava flows on Venus are very young, which in turn would imply that Venus does indeed have active volcanoes.

Author: Suraiya Farukhi | Source: Universities Space Research Association [January 03, 2020]



* This article was originally published here

Lights in the night sky

341 views   27 likes   2 dislikes  

Channel: Terry's Theories  

Two videos 1st video was recorded in France by YouTube channel Lys Orlova. Lys stated she saw these lights above her house at 11:30 at night in Yveline France.
Second video was recorded in Tinley Park Illinois. Uploaded by UFO Watchman.

Source Video 1 : https://www.youtube.com/watch?v=WKHXirDTiA8
Source Video 2 : https://www.youtube.com/watch?v=q32CHZRQtQs

Video length: 2:19
Category: Science & Technology
18 comments

2020 January 7 IC 405: The Flaming Star Nebula Image Credit...



2020 January 7

IC 405: The Flaming Star Nebula
Image Credit & Copyright: Eric Coles and Mel Helm

Explanation: Rippling dust and gas lanes give the Flaming Star Nebula its name. The orange and purple colors of the nebula are present in different regions and are created by different processes. The bright star AE Aurigae, visible toward the image left, is so hot it is blue, emitting light so energetic it knocks electrons away from surrounding gas. When a proton recaptures an electron, red light is frequently emitted (depicted here in orange). The purple region’s color is a mix of this red light and blue light emitted by AE Aurigae but reflected to us by surrounding dust. The two regions are referred to as emission nebula and reflection nebula, respectively. Pictured here in the Hubble color palette, the Flaming Star Nebula, officially known as IC 405, lies about 1500 light years distant, spans about 5 light years, and is visible with a small telescope toward the constellation of the Charioteer (Auriga).

∞ Source: apod.nasa.gov/apod/ap200107.html



* This article was originally published here

Cerrig Arthur Prehistoric Stone Circle, Barmouth, North Wales, 4.1.20.The records state this is a...

Cerrig Arthur Prehistoric Stone Circle, Barmouth, North Wales, 4.1.20.

The records state this is a stone circle although it could perhaps be a cairn and the close knit stones in the centre a ruinous dolmen. Situated high on the hilltops above Barmouth, it commands excellent views.



* This article was originally published here

Scientists pin down timing of lunar dynamo's demise


A conventional compass would be of little use on the moon, which today lacks a global magnetic field. But the moon did produce a magnetic field billions of years ago, and it was likely even stronger than the Earth’s field today. Scientists believe that this lunar field, like Earth’s, was generated by a powerful dynamo — the churning of the moon’s core. At some point, this dynamo, and the magnetic field it generated, petered out.

Scientists pin down timing of lunar dynamo's demise
A new analysis of moon rocks pins down the end of the lunar dynamo, the process by which the moon
once generated a magnetic field [Credit: Hernan Canellas & Benjamin Weiss]
Now scientists from MIT and elsewhere have pinned down the timing of the lunar dynamo’s end, to around 1 billion years ago. The findings appear today in the journal Science Advances.

The new timing rules out some theories for what drove the lunar dynamo in its later stages and favors one particular mechanism: core crystallization. As the moon’s inner iron core crystallized, the liquid core’s electrically charged fluid was buoyantly stirred, producing the dynamo.


“The magnetic field is this nebulous thing that pervades space, like an invisible force field,” says Benjamin Weiss, professor of earth, atmospheric, and planetary sciences at MIT. “We’ve shown that the dynamo that produced the moon’s magnetic field died somewhere between 1.5 and 1 billion years ago, and seems to have been powered in an Earth-like way.”

Weiss’ co-authors on the paper are co-lead authors Saied Mighani and Huapei Wang, as well as Caue Borlina and Claire Nichols of MIT, along with David Shuster of the University of California at Berkeley.

Dueling dynamo theories

Over the past few years, Weiss’ group and others have discovered signs of a strong magnetic field, of around 100 microteslas, in lunar rocks as old as 4 billion years. For comparison, Earth’s magnetic field today is around 50 microteslas.


In 2017, Weiss’s group studied a sample collected from NASA’s Apollo project, and found traces of a much weaker magnetic field, below 10 microteslas, in a moon rock they determined to be about 2.5 billion years old. Their thinking at the time was that perhaps two mechanisms for the lunar dynamo were at play: The first could have generated a much stronger, earlier magnetic field around 4 billion years ago, before being replaced by a second, more long-lived mechanism that sustained a much weaker field, through to at least 2.5 billion years ago.

“There are several ideas for what mechanisms powered the lunar dynamo, and the question is, how do you figure out which one did it?” Weiss says. “It turns out all these power sources have different lifetimes. So if you could figure out when the dynamo turned off, then you could distinguish between the mechanisms that have been proposed for the lunar dynamo. That was the purpose of this new paper.”

Most of the magnetic studies lunar samples from the Apollo missions have been from ancient rocks, dating to about 3 billion to 4 billion years old. These are rocks that originally spewed out as lava onto a very young lunar surface, and as they cooled, their microscopic grains aligned in the direction of the moon’s magnetic field. Much of the moon’s surface is covered in such rocks, which have remained unchanged since, preserving a record of the ancient magnetic field.

However, lunar rocks whose magnetic histories began less than 3 billion years ago have been much harder to find because most lunar volcanism had ceased by this time.

“The past 3 billion years of lunar history has been a mystery because there’s almost no rock record of it,” Weiss says.

“Little compasses”

Nevertheless, he and his colleagues identified two samples of lunar rock, collected by astronauts during the Apollo missions, that appear to have suffered a massive impact about 1 billion years ago and as a result were melted and welded back together in such a way that their ancient magnetic record was all but erased.

The team took the samples back to the lab and first analyzed the orientation of each rock’s electrons, which Weiss describes as “little compasses” that either align in the direction of an existing magnetic field or appear in random orientations in the absence of one. For both samples, the team observed the latter: random configurations of electrons, suggesting that the rocks formed in an extremely weak to essentially zero magnetic field, of no more than 0.1 microteslas.

The team then determined the age of both samples using a radiometric dating technique that Weiss and Shuster were able to adapt for this study.

The team put the samples through a battery of tests to see whether they were indeed good magnetic recorders. In other words, once they were reheated by some massive impact, could they have still been sensitive enough to record even a weak magnetic field on the moon, if it existed?


To answer this, the researchers placed both samples in an oven and blasted them with high temperatures to effectively erase their magnetic record, then exposed the rocks to an artificially generated magnetic field in the laboratory as they cooled.

The results confirmed that the two samples were indeed reliable magnetic recorders and that the field strength they initially measured, of 0.1 microteslas, accurately represented the maximum possible value of the moon’s extremely weak magnetic field 1 billion years ago. Weiss says a field of 0.1 microteslas is so low that it’s likely the lunar dynamo ended by this time.

The new findings line up with the predicted lifetime of core crystallization, a proposed mechanism for the lunar dynamo that could have generated a weak and long-lived magnetic field in the later part of the moon’s history. Weiss says that prior to core crystallization, a mechanism known as precession may have powered a much stronger though shorter-lived dynamo. Precession is a phenomenon by which the solid outer shell of a body such as the moon, in close proximity to a much larger body such as the Earth, wobbles in response to the Earth’s gravity. This wobbling stirs up the fluid in the core, the way swishing a cup of coffee stirs up the liquid inside. 

Around 4 billion years ago, the infant moon was likely much closer to the Earth than it is today, and much more susceptible to the planet’s gravitational effects. As the moon moved slowly away from the Earth, the effect of precession decreased, weakening the dynamo and the magnetic field in turn. Weiss says it’s likely that around 2.5 billion years ago, core crystallization became the dominant mechanism by which the lunar dynamo continued, producing a weaker magnetic field that continued to dissipate as the moon’s core eventually fully crystallized.

The group is looking next to measure the direction of the moon’s ancient magnetic field in hopes of gleaning more information about the moon’s evolution.

Author: Jennifer Chu | Source: Massachusetts Institute of Technology [January 03, 2020]



* This article was originally published here

Tic-Tac & the Triangular shaped UFO's

351 views   41 likes   1 dislikes  

Channel: Terry's Theories  

Where do the Tic-Tac and the Triangular shaped UFOs come from. Many people believe that these crafts are from some distant planet. Well not me. I believe these sightings that have been seen all over the country and the world are made by man. I believe someone or some black budget project corporation has been working on these craft and maybe others in the shadows, and now we are starting to see more of them and getting get warmed up to the idea that theses crafts are real and that they are ours maybe even part of this Space Force that we hear whispers of. I Feel one day soon the hole truth will be revealed to us.
Source Video: Professor Simon Holland https://www.youtube.com/watch?v=_lml2D4eHbQ&t=6s

Video length: 17:46
Category: Science & Technology
22 comments

A Repeating Fast Radio Burst from a Spiral Galaxy

Image of the host galaxy of the Fast Radio Burst (FRB) 180916.J0158+65 as seen with the Gemini-North telescope. The position of the FRB is marked. The inset is a higher-contrast zoom-in of the star-forming region containing the FRB (marked by the red circle). © B. Marcote et al, Nature 2020

Localisation of a new, recurring source of radio flashes deepens the mystery of their origins

The Effelsberg 100-m radio telescope participated in the European VLBI Network (EVN) to observe a repeating Fast Radio Burst (FRB) and helped to pinpoint the FRB to a spiral galaxy similar to our own. Crucial to this work was the sensitivity of the Effelsberg telescope and its flexible pulsar instrument that aided the quick radio localisation. This FRB is the closest to Earth ever localised and was found in a radically different environment to previous studies. The discovery, once again, changes researchers’ assumptions on the origins of these mysterious extragalactic events.

The results are reported in the current issue of the journal Nature by an international team of scientists including Ramesh Karuppusamy from the Max Planck Institute for Radio Astronomy in Bonn, Germany.

One of the greatest mysteries in astronomy right now is the origin of short, dramatic bursts of radio light seen across the universe, known as Fast Radio Bursts or FRBs. Although they last for only a thousandth of a second, there are now hundreds of records of these enigmatic sources. However, from these records, the precise location is known for just four FRBs - they are said to be ‘localised’.

In 2016, one of these four sources was observed to repeat, with bursts originating from the same region in the sky in a non-predictable way. This resulted in researchers drawing distinctions between FRBs where only a single burst of light was observed (‘non-repeating’) and those where multiple bursts of light were observed (‘repeating’).

“The multiple flashes that we witnessed in the first repeating FRB arose from very particular and extreme conditions inside a very tiny (dwarf) galaxy”, says Benito Marcote, from the Joint Institute for VLBI ERIC, the lead author of the current study. “This discovery represented the first piece of the puzzle but it also raised more questions than it solved, such as whether there was a fundamental difference between repeating and non-repeating FRBs. Now, we have localised a second repeating FRB, which challenges our previous ideas on what the source of these bursts could be.”

On 19th June 2019, eight telescopes from the European VLBI Network (EVN) simultaneously observed a radio source known as FRB 180916.J0158+65. This source was originally discovered in 2018 by the CHIME telescope in Canada, which enabled the team to conduct a very high resolution observation with the EVN in the direction of FRB 180916.J0158+65. During five hours of observations the researchers detected four bursts, each lasting for less than two thousandths of a second. The resolution reached through the combination of the telescopes across the globe, using a technique known as Very Long Baseline Interferometry (VLBI), meant that the bursts could be precisely localised to a region of approximately only seven light years across. This localisation is comparable to an individual on Earth being able to distinguish a person on the Moon.

The Effelsberg 100-m radio telescope of the Max Planck institute for Radio Astronomy (MPIfR) played a crucial role in these observations in two ways. With the flexible instruments at this telescope one could record data amenable to rapid identification of radio bursts and a form of data suitable for high resolution radio imaging. Secondly the large collecting area of the telescope makes it an indispensable element in the coordinated interferometric observations of weak sources like this FRB.

With the precise position of the radio source the team was able to conduct observations with one of the world’s largest optical telescopes, the 8-m Gemini North on Mauna Kea in Hawaii. Examining the environment around the source revealed that the bursts originated from a spiral galaxy named SDSS J015800.28+654253.0, located half a billion light years from Earth. The bursts come from a region of that galaxy where star formation is prominent.

“The found location is radically different from the previously located repeating FRB, but also different from all previously studied FRBs”, explains Kenzie Nimmo, PhD student at the University of Amsterdam. “The differences between repeating and non-repeating fast radio bursts are thus less clear and we think that these events may not be linked to a particular type of galaxy or environment. It may be that FRBs are produced in a large zoo of locations across the Universe and just require some specific conditions to be visible.”

“With the characterisation of this source, the argument against against pulsar-like emission as origin for repeating FRBs is gaining strength”, says Ramesh Karuppusamy of the MPIfR, a co-author of the study. “We are at the verge of more such localisations brought about by the upcoming newer telescopes. These will finally allow us to establish the true nature of these sources”, he adds.

While the current study casts doubt on previous assumptions, this FRB is the closest to Earth ever localised, allowing astronomers to study these events in unparalleled detail.

“We hope that continued studies will unveil the conditions that result in the production of these mysterious flashes. Our aim is to precisely localize more FRBs and, ultimately, understand their origin”, concludes Jason Hessels, corresponding author on the study, from the Netherlands Institute for Radio Astronomy (ASTRON) and the University of Amsterdam.

Map of the European VLBI Network (EVN) telescopes used in the observation, showing the positions of the eight participating radio telescopes and also JIVE in The Netherlands. (visibleearth.nasa.gov).




Why Fast Radio Burst localisation is important


While Fast Radio Bursts (FRBs) are a mystery of their own, their study could bring astronomers closer to understanding the Universe itself. In modern cosmology a major question is how structures on all scales were formed. There are computationally expensive simulations to address these questions, but their results strongly depend on the assumed conditions in the early Universe. Results from such simulations need to be compared with actual observations to determine if the simulations provide accurate answers. This is problematic as the majority of matter distributed within galaxies is invisible.

FRBs, however, may offer an elegant solution to this problem in the future. The short pulses from FRBs are “dispersed”, so at longer wavelengths the pulse arrives to Earth slightly later than at shorter wavelengths. This time delay can be measured very accurately, and it is an indirect estimate of the amount of material between the source and the Earth. If thousands of FRBs are found, in all directions, it will be possible to map the distribution of matter across the universe. However, in order to get the true three-dimensional distribution of matter in space, astronomers need to know the distance of each FRB from Earth as well.

How to localise a Fast Radio Burst


In the majority of searches for FRBs a single radio telescope is used to identify the approximate region that the FRB is originating from. However, the use of very high resolution radio observations through Very Long Baseline Interferometry (VLBI) adopts a novel approach.

Currently, the European VLBI Network (EVN) is the only VLBI array that is sensitive enough to study FRBs. In doing so, astronomers are able to determine both the host galaxy and the immediate local environment of the FRB. By determining the host galaxy, astronomers can then use optical observations to analyze the light coming from the galaxy and this can be used to determine its distance from Earth. Studying the environments in which FRBs occur is the key to understanding how these bursts can be produced and which extragalactic objects are associated with them.

“As we continue to unravel the mystery of FRBs, astronomers need to be able to study these sources in incredible detail. The combined sensitivity of the telescopes in the EVN currently provides a unique opportunity to observe these events and we hope that continued observations will contribute to our understanding of these enigmatic sources.” says Francisco Colomer, Director of the Joint Institute for VLBI ERIC.

Institutes and telescopes involved


Institutes involved Observations were conducted with the European Very Long Baseline Interferometry Network (EVN). The EVN is the most sensitive Very Long Baseline Interferometry (VLBI) array in the world, which allows researchers to conduct unique, high-resolution, radio astronomical observations of cosmic radio sources. Data from the EVN is processed at the Joint Institute for VLBI ERIC (JIVE) - an international research infrastructure based in the Netherlands, which also provides support, conducts leading research and forwards technical development in the field of radio astronomy.

A total of eight antennas from the EVN were involved in this observation: 25x38-m Jodrell Bank Mark2, University of Manchester (UK), 25-m Westerbork single-dish, ASTRON (The Netherlands), 100-m Effelsberg, Max Planck Institute for Radio Astronomy (Germany), 32-m Medicina, National Institute for Astrophysics (Italy), 25-m Onsala, Onsala Space Observatory (Sweden), 32-m Toruń, Nicolaus Copernicus University (Poland), 32-m Irbene, Ventspils International Radio Astronomy Centre (Latvia), and 65-m Tianma, Chinese Academy of Sciences (China).

Follow up optical observations were conducted using 8.1-m Gemini North, National Science Foundation’s National Optical-Infrared Astronomy Research Laboratory and Association of Universities for Research in Astronomy (USA).

The authors of the current study comprise B. Marcote, K. Nimmo, J. W. T. Hessels, S. P. Tendulkar, C. G. Bassa, Z. Paragi, A. Keimpema, M. Bhardwaj, R. Karuppusamy, V. M. Kaspi, C. J. Law, D. Michilli, K. Aggarwal, B. Andersen, A. M. Archibald, K. Bandura, G. C. Bower, P. J. Boyle, C. Brar, S. Burke-Spolaor, B. J. Butler, T. Cassanelli, P. Chawla, P. Demorest, M. Dobbs, E. Fonseca, U. Giri, D. C. Good, K. Gourdji, A. Josephy, A. Yu. Kirichenko, F. Kirsten, T. L. Landecker, D. Lang, T. J. W. Lazio, D. Z. Li, H.-H. Lin, J. D. Linford, K. Masui, J. Mena-Parra, A. Naidu, C. Ng, C. Patel, U.-L. Pen, Z. Pleunis, M. Rafiei-Ravandi, M. Rahman, A. Renard, P. Scholz, S. R. Siegel, K. M. Smith, I. H. Stairs, K. Vanderlinde and A. V. Zwaniga with Ramesh Karuppusamy as co-author from MPIfR.



Contact

Dr. Ramesh Karuppusamy
Phone:+49 228 525-108
Email: ramesh@mpifr-bonn.mpg.de
Max-Planck-Institut für Radioastronomie, Bonn

Dr. Jason Hessels
Phone:+31 521 596-769
Email: hessels@astron.nl
ASTRON & The University of Amsterdam, The Netherlands

Dr. Norbert Junkes
Presse- und Öffentlichkeitsarbeit
Phone:+49 228 525-399
Email: njunkes@mpifr-bonn.mpg.de
Max-Planck-Institut für Radioastronomie, Bonn



Original Paper

A repeating fast radio burst source localized to a nearby spiral galaxy

B. Marcote et al., Nature, Online Publication January 06, 2020



Links

JIVE
Joint Institute for VLBI ERIC (JIVE)

Radio Telescope Effelsberg
Effelsberg Radio Telescope

EVN
European VLBI Network (EVN)

A repeating Fast Radio Burst from a Spiral Galaxy
Youtube Movie on FRB 180916.J0158+65.




* This article was originally published here

Tomen y Mur Roman Fort, Baths, Mansio, Vicus, Road, Amphitheatre and Parade Ground, North Wales,...

Tomen y Mur Roman Fort, Baths, Mansio, Vicus, Road, Amphitheatre and Parade Ground, North Wales, 4.1.20.



* This article was originally published here

Wildlife ravaged by Australia fires could take decades to recover


The bushfires raging across Australia have had a devastating impact on the country's unique flora and fauna, with some estimates putting the death toll at nearly half a billion animals in one state alone, and experts believe it could take decades for wildlife to recover.

Wildlife ravaged by Australia fires could take decades to recover
A kangaroo rushes past a burning house amid apocalyptic scenes in Conjola, New South Wales
[Credit: Matthew Abbott/New York Times/Redux/eyevine]
Unprecedented temperatures across the continent have made this season's fires particularly deadly, killing at least 20 people and bringing apocalyptic scenes to an area roughly twice the size of Belgium.


The crisis has focused attention on climate change, which scientists say is creating a longer and more intense bushfire season, and the Australian government has faced widespread criticism over its response and wider environmental policy.

Harrowing footage of desperate koalas drinking from water bottles handed to them by rescuers and kangaroos standing helpless in fire-ravaged towns and charred forests have shocked people across the world.

Wildlife ravaged by Australia fires could take decades to recover
A kangaroo stands on charred vegetation in the aftermath of a bushfire in Wallabi Point,
New South Wales [Credit: Reuters]
There is some hope, however, as experts believe scorched forests can recover in time, and decimated populations of koalas, kangaroos and other badly affected species may be able to return.

A University of Sydney study estimates that 480 million animals have been killed in just the state of New South Wales (NSW) since September 2019, and according to a statement released Friday the authors said the "highly conservative" mortality calculations could mean the toll could be "substantially higher".

In order to reach the figure, the researchers cross-referenced estimates of mammal population density in NSW with areas of vegetation known to have been scorched to work out the death toll, which includes mammals, birds and reptiles, but not insects, bats or frogs.

Wildlife ravaged by Australia fires could take decades to recover
Scientists know from past studies that fires do not spread across the landscape uniformly, and some places
are left remarkably untouched even if areas around them are totally devastated [Credit: AFP]
"The true loss of animal life is likely to be much higher than 480 million," the statement said.


"NSW's wildlife is seriously threatened and under increasing pressure from a range of threats, including land clearing, exotic pests and climate change."

Professor Andrew Beattie from Macquarie University near Sydney told AFP he believes the death toll of animals nationwide could be in the billions, "if you think of mammals, and birds, and reptiles, amphibians and say the larger insects such as butterflies".

Wildlife ravaged by Australia fires could take decades to recover
Posted in r/australia by u/Fierylizard03 [Credit: Reddit]
"We can be pretty sure that in large parts of these very expansive fires, most of the wildlife will be dead," the emeritus professor from the department of biological sciences said.

"The flora and fauna will be gone, and that includes the smaller animals which form the food chain for the bigger ones, which people often don't think about."

Koala populations have been hit particularly hard because they live in trees, feed only on certain types of eucalypts and cannot move quick enough away from the flames.

Wildlife ravaged by Australia fires could take decades to recover
A rescued koala injured in a bushfire in Kangaroo Island [Credit: Dana Mitchell/
Kangaroo Island Wildlife Park via AP]
Even before this year's bushfire crisis, numbers in NSW and Queensland had already dropped by 42 percent between 1990 and 2010, according to the federal threatened species scientific committee.


The plight of the marsupial -- native to Australia -- has been raised in the country's parliament, with Nature Conservation Council ecologist Mark Graham telling lawmakers: "The fires have burnt so hot and so fast that there has been significant mortality of animals in the trees, but there is such a big area now that is still on fire and still burning that we will probably never find the bodies."

Previous studies have found that fires do not spread across the landscape uniformly, and some places are left unscathed even if areas around them are totally devastated.

Wildlife ravaged by Australia fires could take decades to recover
It could take up to 40 years for habitats to return to normal [Credit: AFP]
"It's those areas that are untouched or have suffered less where wildlife tends to accumulate if they can get there," Beattie told AFP, adding that if there are enough of these, the burnt forests should regenerate over time but only if conditions improve quickly.

Asked if there was hope for the repopulation of animals in the worst-hit areas, Beattie said it depends on factors including rainfall, climate and logging, and it could take up to 40 years for habitats to return to normal.


Prime Minister Scott Morrison's handling of the crisis has provoked fury in Australia and further afield, and Beattie said the response, particularly from the federal government, has been "lamentably slow and their attitude is still lamentably casual".

"You've got federal politicians with very little knowledge of the environment, which is, as we are now discovering 'the real world', and hence have not perceived the oncoming catastrophes."

Source: AFP [January 03, 2020]



* This article was originally published here

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