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Mon, 20 Aug 2018
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Strange Skies

Fireball 2

Aboriginal legends reveal ancient secrets to science

Meteor
© BBC
Meteor streaks across the sky against a field of star.
Scientists are beginning to tap into a wellspring of knowledge buried in the ancient stories of Australia's Aboriginal peoples. But the loss of indigenous languages could mean it is too late to learn from them.

The Luritja people, native to the remote deserts of central Australia, once told stories about a fire devil coming down from the Sun, crashing into Earth and killing everything in the vicinity.

The local people feared if they strayed too close to this land they might reignite some otherworldly creature.

The legend describes the crash landing of a meteor in Australia's Central Desert about 4,700 years ago, says University of New South Wales (UNSW) astrophysicist Duane Hamacher.

It would have been a dramatic and fiery event, with the meteor blazing across the sky. As it broke apart, large fragments of metal-rich rock would have crashed to Earth with explosive force, creating a dozen giant craters.

The Northern Territory site, which was discovered in the 1930s by white prospectors with the help of Luritja guides, is today known as the Henbury Meteorites Conservation Reserve.

Bizarro Earth

Plane records flight through mysterious antimatter thundercloud

Thunder Clouds
© NASA
Screenshot NASA YouTube video thunderclouds.
In what sounds like a tale from the Bermuda Triangle, an atmospheric physicist, called Joseph Dwyer, was flying through a massive thunderstorm, when he suddenly found himself in the middle of a huge cloud of antimatter. The physicist was piloting a modified Gulfstream V plane on a scientific mission and came across the strange phenomenon by accident.

Dwyer and his co-pilot mistook a line of thunderstorms for the Georgia coast on their radar, but by the time they realized this, they had no way out.

As they entered the heart of the storm, the scientific instruments on board suddenly began to register something totally unexpected.

The plane was being surrounded by positron-electron explosions causing peaks of high-energy, photon gamma rays - a clear sign of antimatter.

The plane plunged downward and began to shake violently. "I really thought I was going to die," Dwyer said.

So what is antimatter?

ExtremeTech explains that;
"Antimatter is the name we give to particles with the same mass, but opposite charge, as the particles of which we are composed. When an antiparticle comes in contact with its corresponding "normal" particle, they annihilate each other and release gamma rays. In this case, the team detected a large number of positrons (the antiparticle of an electron) in that storm."
But the positrons in the storm seemed to somehow steer themselves towards the plane, and what force did that remains a mystery.
Matter-antimatter annihilation
© CERN
Image of an actual matter-antimatter annihilation due to an atom of antihydrogen captured during a CERN experiment.
It is possible the plane itself was interacting with the antimatter. Nature says that the positrons could have been annihilated in the immediate vicinity of the aircraft, or even on the plane itself.

Aleksandr Gurevich, an atmospheric physicist at the Lebedev Physical Institute in Moscow, suggests that the plane's wings could have become charged, producing extremely intense electric fields around them, causing the creation of positrons.

Bizarro Earth

Scientists image gravity waves through atmosphere

Gravity Waves
© Hanli Liu, NCAR
A model simulation illustrates how gravity waves kicked off by a cyclone east of Australia build as they travel toward space.
Whether it's a drunk camper diving carelessly into a river, or a mass of air rising over a mountain, the rule is the same: What goes up must come down.

With respect to the latter, the rising and falling of air also generates gravity waves. While such atmospheric changes usually only have a regional impact on the lower atmosphere, these ripples can stretch all across the globe in the upper atmosphere and their impact is far more dramatic.

For the first time, researchers have found a way to observe what happens when gravity waves rise towards into the upper atmosphere. A team of researchers at the University Corporation for Atmospheric Research led by Senior Scientist Hanli Liu improved upon the Whole Atmosphere Community Climate Model, pushing it to a resolution fine enough to pick up small gravity waves at their source.

Previously able to clearly view only phenomena that were 2,000 kilometers across, they are now able to view gravity waves when they are still relatively small—only 200 kilometers across—and accurately model how this activity appears later in the upper atmosphere.

Cloud Precipitation

Ice halo forms in St. Croix, Virgin Islands on Mother's day

Image
© stcroixsource.com
A little before noon Sunday, several diners at the new My Brothers Workshop Café and Bakery on Back Street almost leapt from their chairs and charged into the adjacent parking lot to see why some folks were gazing up in the sky.

Turns out it wasn't the end of the world, as someone had suggested. It was a solar halo surrounding the sun, as the name implies; and it seemed to absorb the whole sky.

According to Wikipedia: A halo, also known as a nimbus, is produced by light interacting with ice crystals suspended in the atmosphere, resulting in a wide variety of colored or white rings, arcs and spots in the sky."

Closer to home, University of the Virgin Islands physics professor David Smith shared a professional view on the phenomenon.

"Ice crystals in the upper atmosphere create this halo, like little rainbows," he said. "It's produced by light interacting with the ice crystals."

Smith said the phenomenon isn't all that rare further north.

"It's not as common in the tropics, since there are fewer ice crystals in the upper atmosphere," he said.

Comment: Spectacular sun halo captured over Wirral, UK


Sun

Mother's day sun halo appears in Shanghai, China

Image
© CFP
The solar halo photographed in Chongming County yesterday.
Moms across the city received a gift from the heavens yesterday when a beautiful pearl-colored halo around the sun greeted them on Mother's Day morning.

While some web users saw this as a celestial blessing for Shanghai moms, the Shanghai Meteorological Bureau had a more prosaic explanation.

It was a result of altostratus cloud, formed by the lifting of a large stable air mass, explained forecasters.

That causes invisible water vapor to condense into cloud, creating optical phenomena — such as the sun halo.

Around 10am, many Weibo and WeChat users posted pictures, with many seeing it as a good omen.

According to a Chinese proverb: "When there is a solar halo, it will rain; when there is a lunar halo, it will blow."

And sure enough, rain was forecast overnight.

Cassiopaea

Mysterious supernova still astounds astronomers

Supernova SN 1987A
© NASA/ESA/Hubble
Supernova SN 1987A.
This is Supernova SN 1987A, one of the brightest stellar explosions since the invention of the telescope more than 400 years ago.

Supernova 1987A exploded in the Large Magellanic Cloud, a nearby galaxy about 168,000 light-years away. The light from the supernova arrived here in 1987. Dominating the image are three glowing loops of stellar material, formed when the fast expanding supernova collided with the dense, slower moving material in the stellar wind.

This stellar wind was ejected by the former star about 20,000 years before it went supernova. These collisions cause intense heating and the production of powerful optical and X-ray energy emissions.

Outer, ejected materials lit up first, followed by the innermost materials powered by radioactive isotopes, such as cobalt-56, which decayed into iron-56.

There are still many mysteries surrounding these structures, and their origin remains largely unknown. Another mystery is that of the missing neutron star at the heart of the supernova.

The star that exploded to create SN1987A was a blue supergiant known as Sanduleak -69° 202. Blue supergiants can have surface temperatures of over 50,000°C, and can be a million times as luminous as the Sun.

The violent death of a high-mass star, such as SN 1987A, leaves behind a stellar remnant in the form of either a neutron star or a stellar mass black hole.

However astronomers have been unable to find a neutron star in the remnants of SN1987A, possibly because it's surrounded by an extremely dense cloud of thick dust. It's also possible that so much material fell back onto the neutron star that it further collapsed into a stellar mass black hole.

Galaxy

Mysterious X-rays could mark stellar graveyard

Center of Galaxy
© NASA
Astronomers are baffled by the discovery of a mysterious fog of high energy X-rays blasting out of the centre of our galaxy.

The discovery, reported in the journal Nature, challenges our understanding of the physics taking place in the galactic centre.

The astronomers speculate the mysterious cloud could be generated by a vast graveyard of thousands of stellar remnants clustered in the shadow of the supermassive black hole.

But the source still eludes them.

"This is something that has never been seen before, I only wish we knew what it is that we discovered," says one of the study's authors Professor Chuck Hailey of the University of Columbia in New York.

"We have quite a few theories of what it could be, but none of them fits the facts, so at this point it's something of a mystery."

The international team of scientists discovered the huge X-ray cloud during observations using the NuSTAR X-ray Observatory to study a region 30 light-years wide around the supermassive black hole at the centre of the Milky Way galaxy.

"There really was no evidence to suggest that there should be this diffused foggy type of high energy X-rays in the region around the central black hole," says Hailey.

Bizarro Earth

Rare quadruple rainbow photographed over Long Island, New York

Quadruple Rainbow
© (@amanda_curtis via Twitter, CEO NineteenthAmendment.com
While waiting for her train this morning at the Glen Cove train station in Long Island, NY, Amanda Curtis grabbed her phone and snapped a photo of an incredibly rare atmospheric phenomenon: A quadruple rainbow.

When she posted the photo on Twitter - where it went viral, some folks were incredulous. They said the photo was photoshopped or that Curtis had shot it through glass, causing a reflection.

But, in the interview posted below, Curtis told The Weather Channel the image was authentic and taken in the open air:
At first we thought this quadruple rainbow picture was fake, but then we were blown away. For more amazing weather stories, check out the AMHQ with Sam Champion page on Facebook.

Posted by The Weather Channel on Tuesday, April 21, 2015
The photo was convincing to Paul Neiman, who works as a research meteorologist at NOAA's Earth System Research Observatory.

Airplane

MH370 search may be in the wrong place again

Missing MH370
© Samsul Said/Reuters
A crew member from the Royal Malaysian Air Force looks through the window of a Malaysian Air Force CN235 aircraft during a Search and Rescue (SAR) operation to find the missing Malaysia Airlines flight MH370, in the Straits of Malacca March 13, 2014.
Australia admits it may look at a new patch of ocean. What's more worrying than the undiscovered yet is that not one piece of floating wreckage has been spotted where it should've washed up.

Something significant was missing when senior ministers from Malaysia, Australia and China announced a new effort to find the wreckage of Malaysia Airlines Flight 370 on Thursday. There was no mention of what is fast becoming the most perplexing feature of this multi-layered mystery: why has no floating wreckage turned up?

Make no mistake, the more time that passes without a single piece of floating wreckage being found the stranger it gets.

There is no previous case in the history of modern intercontinental jets where a crash into an ocean has not produced floating wreckage - and within days of the disaster. No matter how violent the impact of an airplane hitting the water there will always be some scattered debris that never sinks.

Last fall the Australian Transport Safety Board, who are directing the sea search for the Boeing 777, said they had assigned a team of experts usually used to predict the path of oil spills to produce a "drift model" - a highly sophisticated calculation combining ocean currents, wind and weather patterns and knowledge of the buoyancy of airplane wreckage - in order to predict when and where wreckage from Flight 370 would appear in places where it would be spotted.

At that time the Australians said that their best guess was that wreckage could take as long as a year to appear and that the most likely place was the long coastline of Western Sumatra on the Indonesian archipelago.

With more than a year gone by nothing has turned up.

Bizarro Earth

Severe geomagnetic storm lights up New Zealand's sky

Aurora Australis
© Stephen Chadwick
The Aurora Australis, or Southern Lights, in the sky at Himatangi Beach on Tuesday night, March 17.
A severe geomagnetic storm has whipped through Earth's magnetosphere, putting on a light show at both ends of the earth.

The storm, which began on Tuesday, is among the strongest in the current 11-year solar cycle, earning a rating of a "severe" G4 on a one-to-five scale, which means it had the potential to affect power grids, high-frequency communications and satellite operations.

Interestingly, there was no radiation storm, which typically accompanies geomagnetic storms of this magnitude. Therefore, NOAA's Space Weather Prediction Center was not expecting disruption to satellite electronics or polar-routed aviation.

But the changes in density in the ionosphere - the very high levels of Earth's atmosphere - could cause more drag on low-orbit satellites, which operators may have to adjust for with thrusters. Simple GPS technology, like the kind in your car or on your smartphone, could be affected in the form of difficulties locating your position.