Strange Skies
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Cassiopaea

Red Alert: massive stars sound warning they are about to go supernova


Royal Astronomical Society
Mon, 10 Oct 2022 18:47 UTC
Supergiant star Betelgeuse
© European Southern Observatory/L. CalçadaThis artist’s impression shows the supergiant star Betelgeuse as it was revealed thanks to different state-of-the-art techniques on ESO’s Very Large Telescope (VLT), which allowed two independent teams of astronomers to obtain the sharpest ever views of the supergiant star Betelgeuse. They show that the star has a vast plume of gas almost as large as our Solar System and a gigantic bubble boiling on its surface. These discoveries provide important clues to help explain how these mammoths shed material at such a tremendous rate.
Astronomers from Liverpool John Moores University and the University of Montpellier have devised an 'early warning' system to sound the alert when a massive star is about to end its life in a supernova explosion. The work was published in Monthly Notices of the Royal Astronomical Society.

In this new study, researchers determined that massive stars (typically between 8 and 20 solar masses) in the last phase of their lives, the so-called 'red supergiant' phase, will suddenly become around a hundred times fainter in visible light in the last few months before they die. This dimming is caused by a sudden accumulation of material around the star, which obscures its light.
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Question

Scientists have detected a 'completely unprecedented' burst of energy in space

Becky Ferreira
Vice.com
Wed, 12 Oct 2022 15:44 UTC
The gamma ray burst is the brightest ever detected in X-rays, according to scientists, and could shed light on the most energetic phenomena in space.
GRB in Space
© SCIENCE PHOTO LIBRARY - MEHAU KULYK VIA GETTY IMAGES
Scientists have spotted an "unprecedented" explosion of energy in space, known as a gamma ray burst (GRB), which appears brighter at some wavelengths than any event of this kind observed so far.

Gamma ray bursts are enormous eruptions fueled by intense cosmic phenomena, such as the deaths of huge stars, and they produce some of the brightest spectacles in the universe. News of this particular burst began rippling across social media following its detection on Sunday by the Fermi Gamma-ray Space Telescope and the Neil Gehrels Swift Observatory, both NASA missions, with some astronomers describing it as "an extraordinary event" and potentially "the brightest GRB ever."

Phil Evans, an astronomer at the University of Leicester who works on Swift's X-ray telescope, colorfully described the burst, known as GRB 221009A, as "stupidly really bright" in a tweet on Monday.

In an email to Motherboard, Evans emphasized that the discovery is so fresh that it will take a while to unpack its significance, but he noted that the burst is "clearly the brightest GRB we've seen in X-rays, at least at the time after the initial explosion that we've observed it."
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Question

Strange ripples have been detected at the edge of the Solar System

Michelle Starr
Science Alert
Tue, 11 Oct 2022 19:04 UTC
Solar System inside the heliosphere
© NASAAn illustration showing the Solar System inside the heliosphere, with the termination shock and heliopause represented by two bubbles, one inside the other.
The bubble of space encasing the Solar System might be wrinkled, at least sometimes.

Data from a spacecraft orbiting Earth has revealed ripple structures in the termination shock and heliopause: shifting regions of space that mark one of the boundaries between the space inside the Solar System, and what's outside - interstellar space.

The results show that it's possible to get a detailed picture of the boundary of the Solar System and how it changes over time.

This information will help scientists better understand a region of space known as the heliosphere, which pushes out from the Sun and shields the planets in our Solar System from cosmic radiation.

There are a variety of ways the Sun affects the space around it. One of those is the solar wind, a constant supersonic flow of ionized plasma. It blows out past the planets and the Kuiper Belt, eventually petering out in the great emptiness between the stars.

The point at which this flow falls below the speed at which sound waves can travel through the diffuse interstallar medium is called the termination shock, and the point at which it is no longer strong enough to push back against the very slight pressure of interstellar space is the heliopause.

Both Voyager probes have crossed the heliopause and are, effectively, now cruising through interstellar space, providing us the first in situ measurements of this shifting boundary. But there's another tool out in Earth orbit that has been helping scientists map the heliopause since it commenced operations in 2009: NASA's Interstellar Boundary Explorer (IBEX).
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Info

Speeding cloud might have come from recent, nearby supernova

Govert Schilling
Sky & Telescope
Fri, 07 Oct 2022 18:23 UTC
Hypervelocity clouds, generally thought to be falling fast into the Milky Way, might have an alternative explanation that places them near us.
supernova explosion
© Leslie ProudfitThis artist’s impression shows the complexity, dynamics, and destruction of a putative supernova explosion in the binary star system 56 Ursa Majoris. The blast carved out a bubble of hydrogen gas, stripped the companion star (lower right) of its outer layers, and sent a high-velocity cloud, dubbed MI, hurtling outward at 120 km/s. MI itself is seen in silhouette against the explosion, as if the central star were wearing a mask.
A mysterious cloud of neutral hydrogen gas, once thought to be falling fast into the Milky Way from its outskirts, might instead be the product of a recent, nearby supernova.

According to solar physicist Joan Schmelz (USRA) and her husband and collaborator, radio astronomer Gerrit Verschuur, the stellar explosion took place some 100,000 years ago, around the time Homo sapiens left Africa and migrated into Asia and Europe.

High-velocity clouds (HVCs) are generally thought to be huge, massive, and many thousands of light-years away. But because there's no good way of measuring their distance, their origin is still unclear. Most astronomers believe they have been blown out of the Milky Way by a process known as a galactic fountain. Alternatively, they could be intergalactic clouds of primordial gas falling prey to our galaxy's gravity.

However, a radio-bright HVC known as MI, which is speeding towards us at 120 kilometers per second (268,000 mph), may be much closer - and thus much smaller and less massive — than previously thought. In a study to appear in The Astrophysical Journal (arXiv preprint available here), Schmelz and Verschuur argue that it was ejected by a dying star, and subsequently accelerated when that star went supernova.
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Info

Astronomers unveil new and puzzling features of mysterious Fast Radio Bursts

Tony Allen
University of Nevada, Las Vegas
Wed, 21 Sep 2022 19:41 UTC
New study by international team of scientists reveals an evolving, magnetized environment and surprising source location for deep-space fast radio bursts - observations that defy current understanding.
Aperture Spherical radio Telescope (FAST) in China
© Jingchuan YuArtist's conception of Five-hundred-meter Aperture Spherical radio Telescope (FAST) in China.
Fast radio bursts (FRBs) are millisecond-long cosmic explosions that each produce the energy equivalent to the sun's annual output. More than 15 years after the deep-space pulses of electromagnetic radio waves were first discovered, their perplexing nature continues to surprise scientists - and newly published research only deepens the mystery surrounding them.

In the Sept. 21 issue of the journal Nature, unexpected new observations from a series of cosmic radio bursts by an international team of scientists - including UNLV astrophysicist Bing Zhang - challenge the prevailing understanding of the physical nature and central engine of FRBs.

The cosmic FRB observations were made in late spring 2021 using the massive Five-hundred-meter Aperture Spherical radio Telescope (FAST) in China. The team, led by Heng Xu, Kejia Lee, Subo Dong from Peking University, and Weiwei Zhu from the National Astronomical Observatories of China, along with Zhang, detected 1,863 bursts in 82 hours over 54 days from an active fast radio burst source called FRB 20201124A.

"This is the largest sample of FRB data with polarization information from one single source", said Lee.

Recent observations of a fast radio burst from our Milky Way galaxy suggest that it originated from a magnetar, which is a dense, city-sized neutron star with an incredibly powerful magnetic field. The origin of very distant cosmological fast radio bursts, on the other hand, remains unknown. And the latest observations leave scientists questioning what they thought they knew about them.
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Info

Cracks are appearing in Earth's magnetic field as the equinox approaches

Jess Thomson
Newsweek
Tue, 13 Sep 2022 15:07 UTC
Magnetic Field
© ISTOCK / GETTY IMAGES PLUSStock image of solar wind hitting the Earth's magnetic field. Due to the alignment of our magnetic field towards the sun at the equinoxes, more solar wind slips through, resulting in more auroras.
So-called cracks in the Earth's magnetic field have led to spectacular aurora light shows being seen in the skies, despite there not having been a solar storm to generate them.

According to spaceweather.com, this is called the Russell-McPherron effect, with cracks in the magnetic field letting more solar wind pass through during the equinoxes, i.e. during the spring and fall equinoxes, where both the day and night are the same length.

"The Rusell-McPherron effect is more of a geometrical effect to do with the orientation of the solar wind's magnetic field and that of the Earth. There is always a cusp or open region of the Earth's magnetic field around the north and south poles so the 'cracks' are permanent," Ciaran Beggan, a geophysicist from the British Geological Survey, told Newsweek.

This solar wind is made of plasma that has been ejected from the sun during a coronal mass ejection (CME), which is usually ejected by sunspots, which have particularly strong coronal magnetic fields. Solar winds are constantly flowing past the Earth, however, they are a lot stronger in the aftermath of a CME
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Info

Rare Byzantine coin may show a 'forbidden' supernova explosion from A.D. 1054

Brandon Specktor
Live Science
Thu, 08 Sep 2022 21:24 UTC
Ancient Coin
© cngcoins.com/Filipovic et alCould one of the two stars near the Emperor's head show a 'forbidden' supernova that lit up the sky over Byzantium for more than a year?
In A.D. 1054, a nearby star ran out of fuel and blew up in a dazzling supernova explosion. Though located 6,500 light-years away, the blast was clearly visible in the skies over Earth for 23 days and several hundred nights after.

The explosion, now known as SN 1054, was so bright that Chinese astronomers dubbed it a "guest star," while skywatchers in Japan, Iraq and possibly the Americas recorded the explosion's sudden appearance in writing and in stone. But in Europe — which was largely ruled at the time by the Byzantine Emperor Constantine IX and the Christian church — the big, bedazzling explosion in the sky was never mentioned, not even once.

Why not? Did the church simply ignore this spontaneous star, or was a more nefarious plot to cover up the reality of the cosmos at play? According to new research, a clue to the answer may hide in an unexpected place: a limited-edition gold coin.

In a study published in the August 2022 issue of the European Journal of Science and Theology, a team of researchers analyzed a series of four Byzantine gold coins minted during the reign of Constantine IX, from A.D. 1042 to 1055. While three of the coins showed only one star, the authors suggest that the fourth coin — which shows two bright stars framing an image of the emperor's head — may be a subtle, and possibly heretical depiction of the supernova of 1054.
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Rainbow

Spectacular rainbow-coloured scarf cloud stunned onlookers in Haikou, China


The Weather Network
Sat, 27 Aug 2022 09:47 UTC
blue
An incredible scarf cloud danced above a town in southern China earlier this week. Here's how this stunning cloud got its rainbow hue.

A town in southern China witnessed a once-in-a-lifetime sight earlier this week when a vibrant rainbow-coloured scarf cloud danced above a towering thunderstorm.

The stunning cloud formed above Haikou, a city of two million in far southern China. A billowing cumulus cloud sprouted in the tropical air over Haikou around sunset. It wasn't the cumulus that drew all the attention—it was the incredible formation that rose above it, called a pileus cloud.

Pileus, sometimes called cap clouds or scarf clouds, are smooth clouds that form atop a growing cumulus or cumulonimbus cloud.

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Cloud Lightning

Rare 'red sprites' seen above Atacama Desert in Chile

Jess Thomson
MSN
Thu, 25 Aug 2022 18:39 UTC
A rarely seen aerial phenomenon involving bright red streaks floating in the sky was photographed above the Atacama Desert in Chile on August 22.

The European Southern Observatory's picture
© Zdenek Bardon/ESOThe European Southern Observatory's picture of the red sprites over the Atacama Desert in Chile, taken from the La Silla Observatory.
The mysterious lights, known as "red sprites," were snapped at the European Southern Observatory's (ESO) La Silla Observatory, in the middle of the desert around 100 miles northeast of the city of Coquimbo.

Red sprites are so rare that they were only photographed for the first time in 1989, although legends of the scarlet lights have been reported anecdotally for centuries.

According to ESO, red sprites are a rare form of lightning very high in the Earth's atmosphere. Occurring between 30 and 55 miles high, in the troposphere layer of the atmosphere, the red lights are caused by large-scale, low-temperature electrical discharges above thunderclouds.
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Solar Flares

Massive solar storm causes STEVE to reappear over North America

Jeff Parsons
Metro (UK)
Thu, 11 Aug 2022 10:58 UTC
The aurora named STEVE (Strong Thermal Emission Velocity Enhancement) and the Milky Way at Childs Lake, Manitoba, Canada
© Krista TrinderThe aurora named STEVE (Strong Thermal Emission Velocity Enhancement) and the Milky Way at Childs Lake, Manitoba, Canada
The scientific phenomenon known as STEVE has been spotted in the night skies above North America this week.

STEVE - short for Strong Thermal Emission Velocity Enhancement - is a long, thin hot slice of gas that cuts through the sky for hundreds of miles.

It's commonly mistaken for part of the Northern Lights, but is in fact something completely different.

Nevertheless, STEVE appears to have been caused by the recent increase in the sun's activity and resulting solar storm currently encircling Earth.



A Showing of STEVE from Alan Dyer on Vimeo.
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