BREAKING NEWS: Galactic Cosmic Rays Accelerating to Unprecedented Levels

At the center of the Milky Way, a new discovery reveals for the first time a source of this cosmic radiation at energies never observed before. The center of our galaxy is home to many objects capable of producing cosmic rays of high energy, including, in particular, a supernova remnant, a pulsar wind nebula, and a compact cluster of massive stars.

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Today we know that cosmic rays with energies up to approximately 100 teraelectronvolts (TeV) are produced in our galaxy, by objects such as supernova remnants and pulsar wind nebulae. Theoretical arguments and direct measurements of cosmic rays reaching the Earth indicate, however, that the cosmic-ray factories in our galaxy should be able to provide particles up to one petaelectronvolt (PeV) at least. While many multi-TeV accelerators have been discovered in recent years, the search for the sources of the highest energy galactic cosmic rays has, so far, been unsuccessful.

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However, “the supermassive black hole located at the center of our galaxy Milky Way, called Sgr A*, is the most plausible source of the PeV protons,” says Felix Aharonian (MPIK, Heidelberg and DIAS, Dublin), adding that, “several possible acceleration regions can be considered, either in the immediate vicinity of the black hole, or further away, where a fraction of the material falling into the black hole is ejected back into the environment, thereby initiating the acceleration of particles.”

The (High Energy Stereoscopic System) H.E.S.S. measurement of the gamma-ray emission can be used to infer the spectrum of the protons that have been accelerated by the central black hole – revealing that Sgr A* is very likely accelerating protons to PeV energies. Currently, these protons cannot account for the total flux of cosmic rays detected at the Earth. “If, however, our central black hole was more active in the past,” the scientists argue, “then it could indeed be responsible for the bulk of the galactic cosmic rays that are observed today at the Earth.” If true, this would dramatically influence the century old debate concerning the origin of these enigmatic particles.

Amateur Metal Detector Finds Ancient Crucifix – May Change Historical Record

An amateur metal detector has made a discovery that experts think could change our understanding of Christianity in Denmark.

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Dennis Fabricius Holm was enjoying an afternoon off work when he found a Birka crucifix pendant in a field near the town of Aunslev, Østfyn.

“I got off early on Friday, so I took just a few hours, I went around with my metal detector and then I came suddenly on something,” Mr Holm told DK.

“Since I cleared the mud and saw the jewelry, I have not been able to think of anything else.”

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On posting the find to social media, other users encouraged him to take it to a museum.

Malene Refshauge Beck, curator and archaeologist at Østfyns Museum said: “It is an absolutely sensational discovery that is from the first half of the 900s [10th century].”

“There is found an almost identical figure in Sweden, which has been dated to just this period.”

However, this specimen is in especially good condition and one of the most well preserved Christian artifacts found in Denmark.

Weighing just 13.2 grams and 4.1cm in length, the figure is made of finely articulated goldthreads and tiny filigree pellets.

It is smooth on the reverse side but has a small eye at the top for a chain.

It was probably worn by a Viking woman.

The dating of the crucifix, estimated at being from 900 – 950AD, is significant because it would indicate Danes embraced Christianity earlier than previously thought.

At the moment, the Jelling Stones – two large rune-stones erected in 965AD in Jutland – are thought to be the oldest known representation of Jesus on a cross in Denmark.

The stones, in the town of Jelling, commemorate Harald Bluetooth’s conversion of the Danes to Christianity.

Christian missionaries had been present in the country for around two hundred years before then, but had failed to convert the Vikings.

However, pressures from Christian trade partners to convert, and in particular, influence from the Kingdom of Germany to the south, meant that most Danes were Christian by the end of the Viking period in 1050.

“The figure can therefore help to advance the time when one considers that the Danes really were Christians,” said Ms Beck.

“Simply because one can say that the person who carried it here no doubt embraced the Christian faith.”

The impact of the find is such that the historical record of the country will need to be adjusted.

“This is a subject that certainly will have to appear in the history books in the future,” said Ms Beck.

“In recent years there has been more and more signs that Christianity was widespread earlier than previously thought – and here the clearest evidence so far.”

 

UPDATE: Comet Flyby Mars’ Magnetic Field and Charged Particles

Jared Espley, a MAVEN science team member at NASA’s Goddard Space Flight Center said; “Comet Siding Spring plunged the magnetic field around Mars into chaos. We think the encounter blew away part of Mars’ upper atmosphere, much like a strong solar storm would.”

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Mars’ atmosphere was very much like Earth’s – that is until an interplanetary collision occurred ripping its protective magnetic field away. However, some managed to remain after the event, additionally; current seasonal climate change continues to produce upper atmospheric plasma which is in fact charged particles.

Comet Siding Spring is also surrounded by a magnetic field as a result of solar wind interacting with plasma generated in the coma, which is the large mass we see as a gaseous cloud. Comet Siding Spring’s nucleus, as are all comets, just a tiny asteroid with remaining ice. In this case, its nucleus is approximately .3 miles (.5 km) in diameter. However, the coma, as with all comets, stretches some 600,000 miles (1,000,000 km) in distance.

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As a result of Earth’s magnetic field weakening with increasing amounts each year, it is time to reconsider the effects of NEOs (Near Earth Orbits). Comets create their own atmosphere by outgassing which contributes to its generating of charged particles. What is less known, is that although asteroids do not have an atmosphere, they do retain predominantly positively charged cosmic rays. They would mostly burnout during entry through Earth’s atmosphere, but as we know, the large ones make it through.

But it is time to recalibrate. Due to a weakening magnetic field, it might be wise to view the small guys with a little more interest and be a little less ambivalent when we hear the newscaster say in their jocular playful manner: “hey, did you hear about the near miss we had last night….

Red Sprites At The Edge Of Space

Solar activity is very low. Nevertheless, space weather continues. High above late-summer thunderstorms in Africa, red sprites are dancing across the cloudtops, reaching up to the edge of space itself. Astronauts onboard the International Space Station photographed this specimen (circled) on March 14th.

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Sprites are an exotic form of “upward lightning.” They are a true space weather phenomenon, inhabiting the upper reaches of Earth’s atmosphere alongside meteors, and some auroras. Some researchers believe sprites are linked to cosmic rays: subatomic particles from deep space striking the top of Earth’s atmosphere produce secondary electrons that, in turn, could provide the spark that triggers the elaborate red forms.

Although sprites have been seen for at least a century, most scientists did not believe they existed until after 1989 when sprites were photographed by cameras onboard the space shuttle. They have since been photographed many times from the ISS.

NASA Station Leads Way for Improved Measurements of Earth Orientation, Shape

NASA has demonstrated the success of advanced technology for making precise measurements of Earth’s orientation and rotation – information that helps provide a foundation for navigation of all space missions and for geophysical studies of our planet.

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The technology includes a new class of radio antenna and electronics that provide broadband capabilities for Very Long Baseline Interferometry, or VLBI. This technique is used to make precise measurements of Earth in space and time.

VLBI measurements have been conducted for decades using a worldwide network of stations that carry out coordinated observations of very distant astronomical objects called quasars. To meet the demand for more precise measurements, a new global network of stations, called the VLBI Global Observing System, or VGOS, is being rolled out to replace the legacy network.

NASA is participating in this next-generation network and just completed the installation of a joint NASA-U.S. Naval Observatory VGOS station at NASA’s Kōke‘e Park Geophysical Observatory in Hawaii. NASA has two other developmental VGOS stations operating at the Goddard Geophysical and Astronomical Observatory at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and at the Massachusetts Institute of Technology’s Haystack Observatory in Westford, Massachusetts.

With this preliminary network, NASA passed a crucial milestone on February 5: conducting the first demonstration anywhere in the world of broadband observations for VLBI over a long baseline.

“The successful tests demonstrate the viability of the new broadband antenna technology for making the kinds of observations needed for improved accuracy in measurements of the very fine-scale shape of Earth,” said Benjamin R. Phillips, who leads NASA’s Earth Surface and Interior Focus Area at NASA Headquarters in Washington, D.C.

The coordinated observation was verified by detection of fringes – an interference pattern indicating that all three stations were receiving and could combine the signals from the quasar they observed.

“The testing has been a concerted effort involving many team members at all three stations, as well as the MIT correlator facility,” said Pedro Elosegui of the Haystack Observatory, which leads the NASA development of the VGOS signal chain.

Several technical hurdles had to be cleared to carry out the long-baseline demonstration. One issue is that the effects of the ionosphere – a layer of Earth’s upper atmosphere that impacts the behavior of radio waves – and of the local weather are quite different at the three sites. Another factor, which applies in any VLBI measurement, is that stations have to contend with interference from nearby radio and cell towers and other sources.

“These and other technical issues have been dealt with,” said Goddard’s Stephen Merkowitz, manager of NASA’s Space Geodesy Project. “We have a few more challenges down the road, but they are manageable. We now know that the new global system can be used the way it was intended.”

The broadband antenna and electronics provide improved sensitivity in a scaled-down package. With dish sizes of 12 to 13 meters (about 39 to 42 feet), the next-generation antennas are designed to be smaller than most of the current system’s dishes, which are typically 20 to 30 meters (about 65 to 100 feet). The scaled-down size allows an antenna to move quickly, conducting up to 100 observations in an hour compared to about 12 observations in an hour for the current VLBI system. This type of antenna is also much less expensive than the larger antennas, making it more economical to deploy and operate a global network.

Broadband capability makes it possible to conduct observations in four bands – that is, at four frequencies – at the same time, whereas current VLBI systems operate in two bands. With four bands, more bits can be recorded at once, so the broadband system can achieve data rates of 8 to 16 gigabits per second, which is about 1000 times the data rate for HDTV. (The current VLBI system has a typical rate of 256 megabits per second.) This leads to better sensitivity, even though the antenna is smaller.

Another new feature is that the four bands are selectable within a range of 2 gigahertz to roughly 14 gigahertz. This helps to avoid interference with other sources, such as radio and cellphone towers.

With the rollout of the VGOS network, existing VLBI stations are being replaced, or in some cases upgraded. More sites will be added in the future to provide more uniform coverage across the globe. Once fully implemented, the worldwide VGOS network is expected to yield position and Earth orientation measurements that improve precision by a factor of three or more, compared to current measurements.

“The next-generation VLBI system will expand our ability to make the kinds of measurements that will be needed for geophysical studies and navigation applications, which demand more precision all the time,” said Merkowitz.

Warming Ocean Water Undercuts Antarctic Ice Shelves

“Upside-down rivers” of warm ocean water threaten the stability of floating ice shelves in Antarctica, according to a new study led by researchers at the University of Colorado Boulder’s National Snow and Ice Data Center published today in Nature Geoscience. The study highlights how parts of Antarctica’s ice sheet may be weakening due to contact with warm ocean water.

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“We found that warm ocean water is carving these ‘upside-down rivers,’ or basal channels, into the undersides of ice shelves all around the Antarctic continent. In at least some cases these channels weaken the ice shelves, making them more vulnerable to disintegration,” said Karen Alley, a Ph.D. student in CU-Boulder’s Department of Geological Sciences and lead author of an analysis published today in Nature Geoscience.

Ice shelves are thick floating plates of ice that have flowed off the Antarctic continent and spread out onto the ocean. As ice shelves flow out to sea, they push against islands, peninsulas, and bedrock bumps known as “pinning points.” Contact with these features slows the flow of grounded ice off the continent. While ice shelves take thousands of years to grow, previous work has shown that they can disintegrate in a matter of weeks. If more ice shelves disintegrate in the future, loss of contact with pinning points will allow ice to flow more rapidly into the ocean, increasing the rate of sea level rise.

“Ice shelves are really vulnerable parts of the ice sheet, because climate change hits them from above and below,” said NSIDC scientist and study co-author Ted Scambos. “They are really important in braking the ice flow to the ocean.”
The features form as buoyant plumes of warm and fresh water rise and flow along the underside of an ice shelf, carving channels much like upside-down rivers. The channels can be tens of miles long, and up to 800 feet “deep.”

When a channel is carved into the base of an ice shelf, the top of the ice shelf sags, leaving a visible depression, or “wrinkle”, in the relatively smooth ice surface. Alley and her colleagues mapped the locations of these wrinkles all around the Antarctic continent using satellite imagery, as well as radar data that images the channels through the ice, mapping the shape of the ice-ocean boundary.

The team also used satellite laser altimetry, which measures the height of an ice shelf surface with high accuracy, to document how quickly some of the channels were growing. The data show that growing channels on the rapidly melting Getz Ice Shelf in West Antarctica can bore into the ice shelf base at rates of approximately 10 meters (33 feet) each year.

The mapping shows that basal channels have a tendency to form along the edges of islands and peninsulas, which are already weak areas on ice shelves. The team observed two locations where ice shelves are fracturing along basal channels, clear evidence that basal channel presence can weaken ice shelves to the point of breaking in vulnerable areas.

Ice shelves are thick floating plates of ice that have flowed off the continent and out onto the ocean. As ice shelves flow out to sea, they push against islands, peninsulas, and bedrock bumps known as “pinning points”. Contact with these features slows the ice flowing off the continent. If ice shelves disintegrate in the future, loss of contact with pinning points will allow ice to flow more rapidly into the ocean, increasing rates of sea level rise.

While no ice shelves have completely disintegrated due to carving by basal channels, the study points to the need for more observation and study of the features, said co-author… “It’s feasible that increasing ocean temperatures around Antarctica could continue to erode ice shelves from below.”

Model Suggests 1812 San Andreas Earthquake May Have Been Set Off By San Jacinto Quake

An assistant researcher professor with California State University has found evidence that the powerful quake that struck southern Californian back in 1812 may have been precipitated by a fault line other than the San Andreas. In his paper published in the journal Science Advances, Julian C. Lozos describes a computer model he created using real world data, what it showed, and why his findings suggest that a future double earthquake could occur someday in the area.

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Back in 1812 a major earthquake struck southern California near what is now San Bernardino—modern study of damage from the quake suggested it was approximately a magnitude 7.5 quake. There was little damage because there were few structures in the area back then, though approximately 40 people were killed when a church they were in collapsed. For many years, Earth scientists have assumed that the quake was due solely to activity along the San Andreas Fault. In this new effort, Lozos suggests that the quake may have actually been set off by a quake along the San Jacinto fault line.

Lozos’ findings are part of a study that included field trips to several sites in an area where the San Andreas Fault and the San Jacinto Fault nearly merge. While there, he found evidence of three strands—where sections of fault are separated by bits of crust that has remained intact—one near the San Andreas fault and two near the San Jacinto fault. Each strand is evidence of an earthquake, but reports from people in the area suggest there were only two earthquakes during the time period under study—in 1812 and 1800, which suggested that one of the strands on the San Andreas Fault and one on the San Jacinto Fault were evidence of the same quake. Lozos also looked at other data collected by other researchers doing working on faults in the area—all of it went into a model he built to describe seismic activity in the area surrounding the time frame of the 1812 quake. The model showed that the most likely scenario that could account for the data that has been collected was that a quake had occurred along the San Jacinto fault line and as it made its way near the San Andreas fault line, the disruption caused a quake to occur along that fault line as well.

Lozos is quick to point out that his model is just that and that thus far he has no evidence to suggest that such a double quake is imminent, but he also notes that if it happened before, it could happen again, noting that southern California is long overdue for a pretty big tumbler.