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Fri, 05 Jun 2020
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Strange Skies

Sun

Solar halo over Mexico City

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A solar halo in Mexico City
A solar halo appeared in Mexico City on Thursday - prompting dozens of calls from worried locals to meteorologists.

The phenomenon, which is actually an optical illusion, is caused when sunlight passes through ice crystals, causing the light to bend into a colourful ring.

Not satisfied with this scientific explanation, locals on social media claimed that an alien invasion was nigh, while other conspirators suggested the government was attempting to blind voters ahead of an election.

The halo was spotted in three cities, most notably above the capital's most famous landmark, the Angel of Independence.


Cloud Lightning

Huge apocalyptic thunderstorm cloud engulfs San Luis Potosi, Mexico

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Thunderstorm cloud over San Luis Potosi
This apocalyptic thunderstorm cloud suddenly appeared in the sky of San Luis Potosi surpising its residents!

That's really a giant cumulonimbus!

This type of giant and angry clouds are more than common in arid or desert areas. But not in San Luis Potosi!


Fire

Photographs of rare red 'lightning' sprites taken in New Mexico and Europe

Image
© Martin Popek
Lightning sprites captured in the Czech Republic on May 13, 2015.

Rarely seen brilliant red sprites were captured by photographers during thunderstorms last week in the Czech Republic and New Mexico.

Sprites are associated with lightning strikes but aren't actually lightning. Instead, sprites occur in the very high levels of the atmosphere above very strong thunderstorms, in the region called the mesosphere between 30 and 60 miles high. Sprites are triggered by positive cloud-to-ground lightning strikes in the storm — which is why they are most common during thunderstorm season — and typically only last a few seconds. They are usually shaped like jelly fish, columns or carrots.

"Sprites are a true space weather phenomenon," lightning scientist Oscar van der Velde of the Technical University of Catalonia, Spain, told spaceweather.com. "They develop in mid-air around 80 km [50 miles] altitude, growing in both directions, first down, then up. This happens when a fierce lightning bolt draws lots of charge from a cloud near Earth's surface. Electric fields [shoot] to the top of Earth's atmosphere - and the result is a sprite. The entire process takes about 20 milliseconds."

Question

What's causing those weird trumpet noises in the sky?

Strange Sounds
© YouTube
A woman reacts to hearing a strange noise coming from the sky in Texas.
Have you heard those weird, apocalyptic trumpet-like noises coming from the sky? People all over the world say they have.

So what are they? The short answer is no one knows.

The latest video of the mystery comes from Germany and was posted to YouTube last month.

In it, the puzzled photographer sticks a camera out the window as a woman asks in German, "What is that?"

In the background is heard a metallic-type groaning sound coming from the sky as if someone just put the key in the ignition of a large, invisible Close Encounters of the Third Kind kind of vehicle and started it up. The video is all the more eerie because a young boy is standing motionless in the street as the noise amplifies.

Take a listen. What do you think that is?


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

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© 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.