The night sky is in danger. This has been true for years as urban landscapes became increasingly light-polluted. But now there's a new threat, one you can't escape by driving into the countryside. It's the "mega-constellation." Some companies are planning to launch tens of thousands of internet satellites into low-Earth orbit. The recent launch by Space X of just 240 Starlink satellites has already ruined many astronomical observations.

This week the International Astronomical Union (IAU) issued a new press release describing the impact of satellite mega-constellations on astronomy. IAU astronomers simulated 25,000 satellites similar in type to the satellites of SpaceX, Amazon, and OneWeb, and here are their results:
1. The number of satellites above the horizon at any given time would be between ~1500 and a few thousand. Most will appear very close to the horizon, with only a relative few passing directly overhead.
2. When the sun is 18 degrees below the horizon--that is, when the night becomes dark--the number of illuminated satellites above the horizon would be around 1000. These numbers will decrease during the hours around midnight when many satellites fall into Earth's shadow.
3. At the moment it is difficult to predict how many of the illuminated satellites will be visible to the naked eye because of uncertainties in their reflectivity. Probably, the vast majority will be too faint to see. This depends to some degree on experiments such as those being carried out by SpaceX to reduce the reflectivity of their satellites with different coatings.

4. Even if most satellites are invisible to the naked eye, mega-constellations pose a serious problem for professional astronomy. The trails of these satellites are bright enough to saturate modern detectors on large telescopes, and wide-field scientific astronomical observations will be severely affected.
5. The Vera C. Rubin Observatory currently under construction in Chile will be particularly hard-hit. The innovative observatory will scan large swaths of the sky, looking for near-Earth asteroids, studying dark energy, and much more. According to the IAU, up to 30% of the 30-second images during twilight hours will be affected. In theory, the effects of the new satellites could be mitigated by accurately predicting their orbits and interrupting observations, when necessary, during their passage, but this is a burdensome procedure.

There are no international rules governing the brightness of orbiting manmade objects. Until now, they didn't seem to be necessary. Mega-constellations, however, threaten "the uncontaminated view of the night sky from dark places, which should be considered a non-renounceable world human heritage," says the press release. Therefore the IAU will present its findings at meetings of the UN Committee for Peaceful Uses of Outer Space, bringing the attention of this problem to world leaders.
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Betelgeuse, in the constellation Orion,  isn't just dimming, it's also changing shape. Today, the European Southern Observatory released new images of Betelgeuse from the Very Large Telescope (VLT) in Chile's Atacama desert. The unstable red supergiant is definitely lopsided.

A team led by Miguel Montargès of KU Leuven in Belgium took the following picture in Dec. 2019, shortly after the star began its unprecedented dimming. They were able to compare it to a "normal" picture of Betelgeuse taken 11 months earlier. The change in shape is striking.

What's going on? The researchers aren't sure why Betelgeuse looks so different, but they suspect the involvement of dust. Red supergiants like Betelgeuse create and eject vast amounts of dusty material, losing mass even before they explode as supernovas. The lopsided shape and dimming of Betelgeuse might be explained if a cloud of dust is partially blocking its disk. Indeed, VLT infrared observations of Betelgeuse at the same time reveal lots of dust around the star.

Mystery solved? Not necessarily. "Our knowledge of red supergiants remains incomplete, and this is still a work in progress, so a surprise can still happen," notes Montargès. Other possibilities include magnetic activity on Betelgeuse's surface (such as a giant starspot) and, of course, the early stages of a supernova explosion.

The Very Large Telescope with its adaptive optics instruments is one of the few facilities in the world capable of imaging the surface of Betelgeuse, located more thann 600 light years away. More images from the Atacama desert may yet reveal what's happening--if Betelgeuse doesn't tell us first!
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A new type of aurora is rippling across Arctic skies. Citizen scientists who discovered it nicknamed it "The Dunes" because of its resemblance to desert sand dunes. A paper published in the Jan. 28th issue of AGU Advances describes the new form and the unexpected physics that causes it.

Dune-shaped auroras form in a narrow altitude range 80 km to 120 km above Earth's surface. Turns out, this is an extremely hard-to-study layer of Earth's atmosphere. It's too high for weather balloons, and too low for rockets.

"Due to the difficulties in measuring atmospheric phenomena between 80 and 120 km, we sometimes call this region 'the ignorosphere'," says Minna Palmroth, Professor of Computational Space Physics at the University of Helsinki and the lead author of the study.

Sky watchers in the Arctic have been seeing Dunes for years without understanding what they were. A breakthrough came on Oct. 7, 2018, when multiple groups photographed the dunes from widely separated locations in Finland. Maxime Grandin, a postdoctoral researcher in Palmroth's team, analyzed the images, using triangulation techniques to decipher the Dune's geometry.

Conclusion: Dunes are located ~100 km high--smack-dab in the middle of the ignorosphere--and have a pure, monochromatic wavelength of about 45 km.

Above: An artists' concept of a mesospheric bore trapped in a high-altitude waveguide. [more]

The research team believes the Dunes are a "mesospheric bore"--a type of atmospheric gravity wave that springs up from the surface below and gets caught in a thermal waveguide ~100 km high. When solar wind particles rain down on the bore, they illuminate its rippling structure.

The discovery of Dunes may allow researchers to study the ignorosphere as never before. Monitoring Dunes can reveal previously hidden waves and waveguides at the boundary between Earth and space. Aurora photographers, have you seen a Dune? Submit your photos here.
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MIT Technology Review; Fri, 21 Jun 2019 18:43 UTC

The Tibetan Plateau is a vast elevated plain almost five kilometers above sea level, sometimes called the Roof of the World. It is bordered to the south by the world's highest mountain range and to the north by desert lands. It is one of the most isolated places on Earth.

But the extreme altitude makes it a useful place for scientists. In 1990, they built an observatory here to study the showers of subatomic particles that rain down from the upper atmosphere whenever it is hit by a high-energy cosmic ray. This work is better done at high altitude because there is less atmosphere to absorb the particles.

Since then, the so-called Tibet Air Shower Array has recorded vast numbers of high-energy cosmic rays, particles accelerated to huge energies by astrophysical phenomena such as supernovas, active galactic nuclei, and mysterious as-yet-unidentified sources.

But the array also picks up air showers caused by a different source - high-energy photons. These mysterious photons are also created by astrophysical phenomena such as the interaction between high-energy particles and the cosmic microwave background. Consequently, they can provide a unique insight into these processes and the environments in which they occur.

Over the years, the Tibet Air Shower Array has spotted plenty of these photons with energies up to dozens of teraelectronvolts (TeV 1012). That's roughly equivalent to the highest-energy photons that can be created on Earth. But nobody has ever observed more powerful photons.

Until now. Today, researchers from the Tibet Air Shower Gamma Collaboration say they have observed photons with energies above 100 TeV for the first time, including a remarkable photon with an energy of almost 500 TeV. This single photon has about the same energy as a falling Ping-Pong ball and is the highest-energy photon ever recorded.

The collaboration has also worked out where these photons are coming from: the Crab Nebula, the remnants of a supernova that occurred in 1054 AD in the Perseus Arm of the Milky Way, some 6,500 light-years from Earth.

.... read more at https://www.sott.net/article/415559-Earth-hit-by-highest-energy-photons-ever-recorded-from-the-Crab-Nebula

A long time ago in a galaxy far, far away.... a star exploded. Light from the supernova reached Earth in May 2019 following a journey of 110 million years across the cosmos. Astronomers saw it--a tiny bloom of light on the edge of lenticular galaxy NGC5353--and immediately began to monitor its light curve. Then this happened:

Bill Williams of the Chiefland Astronomy Village in Florida created the composite image. "It shows my photo of the supernova on May 15th (left), one week before the launch of SpaceX's Starlink satellites, alongside a similar photo taken at the Lowell Observatory after the launch (right)", explains Williams. The difference is, Starlink ruined the Lowell Observatory image.
SN2019ein is a Type 1a supernova. It happened when matter from one star fell onto another--a nearby white dwarf, pushing the mass of the dwarf over the threshold for a supernova explosion. This special kind of supernova is a "standard candle", which cosmologists have used to show that the expansion of the universe is accelerating. Monitoring the light curves of Type 1a supernova literally helps us understand the fate of the cosmos.
"To me, as a dedicated observer of the night sky for over 50 years and an avid underwater photographer, satellite megaconstellations such as Starlink are the equivalent of polluting our oceans with plastics", notes Williams. "I hope we take every measure possible to mitigate the effects of satellite light pollution of our night skies."
The International Astronomical Union seems to agree. Read their statement here.
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A minor interplanetary shock wave hit Earth on May 26th at approximately 22:00 UT. The CME-like disturbance was unexpected. It caused the density of the solar wind around Earth to abruptly quadruple, while the interplanetary magnetic field doubled in strength. Minor geomagnetic storms are possible on May 27th as our planet passes through the shock wave's wake.
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The Holographic Fractal Universe concept and the 'Black Whole' view, promulgated by Physicists Nassim Haramein and Dr. Elizabeth Rauscher.

NASA has clocked up numerous amazing technological feats of engineering and ingenuity for decades, but a recent video from the space agency shows just how much work they have cut out for them.

In just the last few years, NASA has provided some incredible perspectives on our own planet, including stunning images of some of the Earth's most majestic natural phenomena.

Not content with studying our own backyard, the agency has beamed back photos and videos from Mars thanks to its now-deceased rover, not to mention orbiting far-flung asteroids to try and understand the origins of the universe itself.

In an attempt to explain the vastness of their field of study, NASA helpfully put together a short explainer video showcasing the mindblowing scale of the Milky Way galaxy.

NASA's Parker Solar Probe is now closer to the sun than any other spacecraft in history, shattering the previous record of 26.6 million miles set by the Helios 2 spacecraft in 1976. The probe is now well inside the orbit of Mercury."It's a proud moment for our team," says Project Manager Andy Driesman of the Johns Hopkins Applied Physics Laboratory.

Count to 3. Parker just broke the record again. The spacecraft is accelerating sunward for the mission's first perihelion on Nov. 5th. At closest approach, the solar disk will seem 6 times wider than it does on Earth as the probe is hit by "brutal heat and radiation" (NASA's words). Parker's carbon-composite heat shield is expected to heat up to a sizzling 2000 deg. F.
Parker's prime mission is to investigate the origin of the solar wind--a project best done uncomfortably close to the star. Parker will trace the solar wind back to its source and find out how it escapes the sun's gravity and magnetic confinement.
Russell Howard of the Naval Research Laboratory expects to learn a lot from this encounter. "We might detect magnetic islands in the solar wind, which have been theoretically predicted. And if a CME (solar explosion) happens or a comet passes through the sun's atmosphere while we are so nearby, it could be spectacular."

Howard is the principal investigator for WISPR, the probe's wide-field camera system. WISPR can actually see the solar wind, allowing it to image clouds and shock waves as they approach and pass the spacecraft. Other sensors on the spacecraft will sample the structures that WISPR sees, making measurements of particles and fields that researchers can use to test competing theories.
"We lose communication with the spacecraft during the perihelion period which begins next week," notes Howard. "This is because there isn't sufficient power to drive both the instruments and the transmitter. The first dump of data will occur in early December." Stay tuned for that.
Parker will plunge toward the sun 24 more times in the next 8 years, breaking many records en route. Here's the timeline.
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Hamza Khalid: Scicademy: 18 Nov 2017

Wormholes are fascinating (but theoretical) cosmological objects that can connect two distant regions of the universe. They would allow one to create "shortcuts" through space in order to travel vast distances in a shorter period of time. They are predicted by the general Theory of Relativity, and are what Einstein referred to as "bridges" through space-time. Wormholes are mathematically predicted, if not proven, and a new study illustrates how scientists have taken these theoretical anomalies - which many physicists believe to be real - and created one for them.

Researchers in Spain, from the physics department at the Autonomous University of Barcelona, have actually created a magnetic wormhole in a lab that tunnels a magnetic field through space.

Using metamaterials and metasurfaces, our wormhole transfers the magnetic field from one point in space to another through a path that is magnetically undetectable. We experimentally show that the magnetic field from a source at one end of the wormhole appears at the other end as an isolated magnetic monopolar field, creating the illusion of a magnetic field propagating through a tunnel outside the 3D space.

Just to be clear, the manufactured wormhole is not able to transport matter, it's able to transport a magnetic field from a physical object by having it disappear at one point, and then reappear at another, which is still very significant in the world of science.

The rest of this article can be read here: https://www.sott.net/article/377792-A-magnetic-wormhole-that-connects-two-regions-of-space-has-been-created-by-scientists

Last night, cameras in Czechia recorded a magnificent display of sprites leaping up from a thunderstorm in neighboring Austria. Photographer Martin Popek of Nýdek, Czechia, selected this specimen from many frames he recorded:

"The storm was about 390km away," says Popek, "and the sprite was huge. It stretched 50 km to 90 km above the ground below."Sometimes called "space lightning," sprites are a true space weather phenomenon. They inhabit the upper atmosphere alongside auroras, meteors and noctilucent clouds. Some researchers believe they 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 sprites.

The link to cosmic rays is particularly interesting at this time. Despite a brief reduction in cosmic rays last week caused by the sweeping action of a passing CME, cosmic rays are intensifying. For the past two years, space weather balloons have observed a steady increase in deep space radiation penetrating our atmosphere. This increase is largely due to the decline in the solar cycle. Flagging solar wind pressure and weakening sunspot magnetic fields allow more cosmic rays into the inner solar system--a trend which is expected to continue for years to come.  [higher vibrational light/energy penetrating our solar system and Earth. MS]  These changes could add up to more sprites.

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. Now "sprite chasers" routinely photograph sprites from their own homes. "I used up a Watec 910HX security camera with UFOCapture software to catch my sprites," says Popek.

Andrew Liptak : The Verge : 16 Jan 2017

The Japanese probe Akatsuki has observed a massive gravity wave in the atmosphere of Venus. This is not the first time such a wave was observed on the Solar System's second planet, but it is the largest ever recorded, stretching just over 6,000 miles from end to end. Its features also suggest that the dynamics of Venus' atmosphere are more complex than previously thought.

An atmospheric gravity wave is a ripple in the density of a planet's atmosphere, according to the European Space Agency. (This isn't a gravitational wave, which is a ripple in space-time.) We have these waves in Earth's atmosphere, too; they interfere with weather and cause turbulence. Scientists have observed atmospheric gravity waves on Venus before: the European Space Agency's Venus Express spotted several before the end of its mission in 2014. Since its initial observations, Akatsuki has spotted several smaller structures with its infrared cameras in April and May 2016.

Akatsuki spotted this particular gravity wave, described in a paper published today in Nature Geoscience, when the probe arrived at the planet on December 7th, 2015. The spacecraft then lost sight of it on December 12th, 2015, because of a change in Akatsuki's orbit. When the probe returned to a position to observe the bow-shaped structure on January 15th, 2016, the bright wave had vanished.

What sets the huge December wave apart from previously discovered ones is that it appeared to be stationary above a mountainous region on the planet's surface, despite the background atmospheric winds.

The study's authors believe that the bright structure is the result of a gravity wave that was formed in the lower atmosphere as it flowed over the planet's mountainous terrain. It's not clear how the wave exactly propagates to the planet's upper atmosphere, where clouds rotate faster than the planets itself — four days instead of the 243 days it takes Venus to rotate once.

The massive gravity wave might mean that the atmospheric conditions closer to the planet's surface are more variable than predicted.

This month, a lot is happening in the mesosphere. The mesosphere is a layer of Earth's atmosphere above the stratosphere; it is the realm of sprites, noctilucent clouds (NLCs), and airglow. Starting on Nov. 17th, NASA's AIM spacecraft spotted bright noctilucent clouds forming in the mesosphere above Antarctica. Then, in an apparently unrelated development on Nov. 24th, the normal dome of airglow over China split in two. Xiao Shuai photographed the event from Mount Balang in Sichuan:

This is called a "mesospheric bore"; a type of atmospheric wave with deep ripples at its leading edge.  Indeed, you can see the ripples in Shuai's photo separating the zone of airglow from clear sky.

Bores fall into the category of "gravity waves"—so called because gravity acts as the restoring force essential to wave motion. Analogy: boats in water. When a boat goes tearing across a lake, water in front of the boat is pushed upward. Gravity pulls the water back down again and this sets up a wave.  In this case, instead of water, rarefied air is the medium through which the wave propagates.  The sudden boundary in the airglow layer is probably akin to a hydraulic jump.  But what created the disturbance in the first place?  (What is the 'boat'?) No one knows.

"There may be more updates in the coming days as scientists from NASA and the Chinese Academy of Science check data from satellites to learn more about this event," says Jeff Dai, who has been helping Xiao Shuai process and communicate his extraordinary images. 
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The biggest radio telescope located in China's Guizhou Province is now operational. Featuring a reflector the size of 30 football pitches, it took five years and $180 million to construct. Called the Five-hundred-meter Aperture Spherical Telescope's (FAST), the telescope is located in a karst valley in Pingtang County, a mountainous area in southwest China.

Some 8,000 local residents were relocated to ensure a 5km radio silence zone around the facility. About $269 million were allocated to pay compensations to the villagers. The name FAST referrers to the main structure of the gigantic instrument, which has 4,450 triangular 11-meter panels and measures 500 meters in diameter. For comparison, the Arecibo Observatory in Puerto Rico, which held the title of world's largest radio telescope before FAST, has a 305-meter dish.

FAST was first brought online in July for trial observation and received a set of data from a pulsar about 1,351 light-years away, as Xinhua news agency was told by Qian Lei, an associate researcher with the National Astronomical Observation (NAO) under the Chinese Academy of Sciences, which built the project. China plans to use one of its best supercomputers, the SkyEye-1, to process the massive amounts of data supplied by FAST. At its peak the data flow is expected to require computing power of over 200 teraflops per second.

The instrument would be used to study gravitational waves, stellar radio emissions and potentially signals from extraterrestrial civilizations, Qian Lei, an associate researcher with the National Astronomical Observatories of the Chinese Academy of Sciences, told state broadcaster CCTV. "In theory, if there is civilization in outer space, the radio signal it sends will be similar to the signal we can receive when a pulsar [spinning neutron star] is approaching us," Qian said.

FAST is the world's biggest radio telescope with a single dish. The old Soviet RATAN-600 in southern Russia is bigger still, but, unlike China's new telescope, its 576-meter reflector structure resembles a donut.

Scientists have been taken by surprise to discover that a galaxy they thought was tiny and conventional is, in fact, enormous and bizarre - and quite unlike anything they have seen before. 
At about 718,000 light-years across, UGC 1382 is more than seven times wider than the Milky Way - 10 times larger than was previously thought. But that isn't the strange part.

Whereas most galaxies have the oldest stars closer to the centre, this one is the reverse.  "The centre of UGC 1382 is actually younger than the spiral disc surrounding it," says Mark Seibert of the Observatories of the Carnegie Institution for Science, in California.  "It's old on the outside and young on the inside. This is like finding a tree whose inner growth rings are younger than the outer rings."

Seibert and Lea Hagen of Pennsylvania State University found the galaxy by accident while they were looking for stars forming in run-of-the-mill elliptical galaxies - of which they thought UGC 1382 was one.  But when they started looking more closely at images in ultraviolet light through data from NASA's Galaxy Evolution Explorer (GALEX), they were amazed to see a vast expanse of stars that shouldn't have been there.

"We saw spiral arms extending far outside this galaxy, which no one had noticed before, and which elliptical galaxies should not have," said Hagen, lead author of a study to be published in the Astrophysical Journal. "That put us on an expedition to find out what this galaxy is and how it formed."
The rest of this story can be read here.