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Wed, 22 Aug 2018
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Strange Skies

Moon

Stunning lunar halo seen over Chile's Atacama Desert

Moon halo over Chile
© Yuri Beletsky
Observers at the La Silla Observatory on the border of Chile's Atacama Desert were studying the stars and constellations last week when they saw something spectacular: A bright lunar halo had formed in front of the Orion constellation and Sirius, the brightest star in our sky.

The technical term for a lunar or solar halo is a "circumscribed halo." Similar to sun dogs, lunar and solar halos belong to the family of ice halos, which are optical phenomena formed by the refraction of sun on hexagonal ice crystals suspended high up in the atmosphere, most commonly in cirrus clouds. These are also known as 22-degree halos, because the ring of light forms 22 degrees from the sun.

Cirrus clouds are made up of millions of tiny ice crystals. When the light from the sun or moon hits these crystals in just the right way, the light refracts and reflects. It's this interaction between the light and the hexagonal ice crystals that forms the ring around the moon.

Telescope

Rare video of aurora phenomenon "Steve" - formally discovered in 2017

steve april 10 2018
On April 10th, a G1-class geomagnetic storm was brewing over Canada as a stream of solar wind buffeted Earth's magnetic field. Matthew Wheeler of Robson Valley, British Columbia, stepped outside to see what was up--and STEVE appeared. "My dog barked at it for the entire hour it was visible," says Wheeler. "It was flowing like a river at astonishing speed."

STEVE may look like an aurora, but it is not. For one thing, it is soft purple, not green like typical auroras. And it has its own special form--tightly collimated into a narrow ribbon that can bisect the entire sky.

Researchers are only beginning to understand the phenomenon--aided by a chance encounter between STEVE and a European satellite a few years ago. In situ measurements revealed that STEVE is a hot (3000 degrees C) ribbon of ionized gas slicing through Earth's upper atmosphere some 300 km above the ground. It appears unpredictably during some, but not all, geomagnetic storms.

Comment: He may have noticed it in the 1980's but it has only officially been recognised since around 2017, and was a surprise to many veteran aurora guides - and interestingly, sightings of Steve are on the increase:


Info

Proxima Centauri roasts an exoplanet with a solar flare

Proxima Centauri
© ESO/M. Kornmesser
Located in one of the closest star systems to our own at just 4.2 lightyears away, the exoplanet Proxima b seemed like a great candidate for a space colony once we're capable of that sort of thing. Not so much anymore.

Because even though Proxima b is in that solar system's habitable zone (often called its "goldilocks zone"), its star Proxima Centauri seems to be more volatile than our sun. Proxima Centuari has been detected unleashing a giant solar flare of approximately 316,227,766,000 petajoules (316,227 petawatts). It was powerful enough that the normally dim red dwarf star could be seen from Earth.

It was also powerful enough that it may have fried any life living on the surface of Proxima b, and this may be common enough that future settlements there wouldn't last very long.

Now, it's unlikely that any life was sitting on the surface while this event occurred. One reason is that the chances of life forming so close are slim, and we have no evidence of any life there beyond that the planet is usually the right temperature for liquid water to form.

Info

Astronomers can't explain 72 stellar explosions

Supernova
© M Pursiainen, Univ Southampton & DES collaboration
Images of one of the transient events.
Gone in a (cosmological) flash: a team of astronomers found 72 very bright, but quick events in a recent survey and are still struggling to explain their origin.

Miika Pursiainen, PhD researcher from the University of Southampton, presented the new results at the European Week of Astronomy and Space Science in Liverpool.

Pursiainen and his collaborators found the transients in data from the Dark Energy Survey Supernova Programme (DES-SN). This is part of a global effort to understand dark energy, a component driving an acceleration in the expansion of the Universe. DES-SN uses a large camera on a 4-metre telescope in the Cerro Tololo Inter-American Observatory (CTIO) in the Chilean Andes. The survey looks for supernovae, the explosion of massive stars at the end of their lives. A supernova explosion can briefly be as bright as a whole galaxy, made up of hundreds of billions of stars.

The researchers found the largest number of these quick events to date. Even for transient phenomena, they are very peculiar: while they have a similar maximum brightness to different types of supernovae they are visible for less time, from a week to a month. In contrast supernovae last for several months or more.

Info

Supernovae and a new storm on Saturn

Comet C/2017 O1 (ASASSN1)
© Dr Paolo Candy
Taken by Dr Paolo Candy on September 14, 2017 @ Ci.A.O. Cimini Astronomical Observatory - Italy.
Welcome to a new and occasional blog about the transient universe. We're calling it "Big Scope Breakout." Every Wednesday, I post the "Explore the Night" blog here at Sky & Telescope, where we explore brighter comets, exploding stars, and fascinating deep sky objects. But a lot of unanticipated sky events can happen in a week - supernovae, Earth-approaching asteroids, and comet discoveries, to name just a few.

To better serve observers with larger instruments in a timely manner, we're going to get that news to you ASAP, so you can spot these transient events before the clouds close in, the Moon returns, or the target fades from view. Some of the most exciting sights can be rather dim, so expect to see more reports of fainter objects than brighter. Of course, that won't always be true. It all depends on what the cosmos has on the menu.

This week we're bananas with supernovae and novae, plus there's a new storm on Saturn.

Snowflake

Adapt 2030 Ice Age Report: Cathedrals in snow UK, lenticular clouds glow and feet more of snow for Europe

snow scotland
After five days of snow in Scotland, Northern UK and Ireland due to late season April snows leave the landscape, cathedrals, castles and churches blanketed in white. More deep lows on the way to southern UK over the week. Up to five more feet of snow on tap for Italian Alps and three feet for French Alps. Slovenia un-measurable snow pack for the season and high winds bring lenticular clouds in the sunset. Topping things off North Pole forecast is -20C / -4F for April 05, 2018.


Sources

Comment: See also: Death toll for Scotland's lambs sees a sharp increase after heavy snow

Depth of snow in the Alps hits 7 metres, Swiss ski resort gets 5 feet of snowfall in 7 days


Cloud Lightning

'Rare' red sprite season begins early with elusive bolts snapped during storm over Czech republic

red sprites april 4 2018
© Martin Popek
Red sprites over western Czeckia on April 4, 2018
Two red sprites, transient optical phenomena appearing as luminous reddish-orange flashes, have been recorded over the Czech Republic on April 4, 2018, marking the early beginning of 2018 sprite season in the northern hemisphere.

Lucky photographer this season was again well known Martin Popek who captured them above storms over western Czeckia on April 4 below Pleiades star cluster:

Because sprites are associated with thunderstorms, they tend to occur in late spring and summer. However, western and central Europe recorded more than 100 000 lightning strikes over the past 48 hours. It was enough to produce sprites and allow us to photograph them.

"Sprites are a true space weather phenomenon," lightning scientist Oscar van der Velde of the Technical University of Catalonia in Spain explained. "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."

Comment: See also: Also check out SOTT radio's: Behind the Headlines: Earth changes in an electric universe: Is climate change really man-made?


Cloud Grey

Bizarre cloud formation over western Arizona turns heads

Bizarre cloud over AZ
© Twitter/Madalyn Heimann
A bizarre cloud formation over western Arizona Monday night had locals in Phoenix and Yuma pondering whether there was a rocket launch out of California's nearby Vandenberg Air Force Base or maybe even a visit from some rainbow friends.

However, there were no rocket launches scheduled to take place at the base Monday night, so it is most likely to be a curious cloud phenomenon, KVOA reported.

According to some viewers, the formation looked like cloud iridescence, which occurs when tiny water droplets or ice crystals in clouds diffract light producing beautiful rainbow colors in clouds.

Cloud Lightning

Adapt 2030 Ice Age Report: Elements of the Grand Solar Minimum easily explained

deep snow
A graphic to describe all of the changes we as a planetary civilization will see unfold over the next 7 years culminating in reduced global crop production. We collectively need to start the conversation so we can begin to find solutions. What to expect: 1. Declining Solar Output 2. Weakening Magnetosphere 3.Out of season storms 4. Massive rain events, rivers from the sky 5.Huge and ever increasing size of hailstones 6. Increased meteor sightings and rattling explosions 7. Jet Streams wandering far out of their normal zones 8. Increases in cosmic rays which will trigger more eruptions and create thicker cloud layers 9. REDUCTION IN GLOBAL GRAIN YIELDS


Cassiopaea

Scientists observed one of the fastest, brightest supernovas on record

Supernova
© Getty
A speedy supernova hit maximum brightness in just a few days.
The quickest supernova we've ever seen went from invisible to extraordinarily bright in only 2.2 days. It is the first of these speedy stellar explosions that's been observed thoroughly enough to help us figure out exactly how they work.

Supernovae are massive explosions that happen when a star burns out. They usually take weeks or months after the death of the star to reach maximum brightness, and even longer to fade away. But Armin Rest at the Space Telescope Science Institute in Baltimore, Maryland and his colleagues found one in data from the Kepler Space Telescope that rose to peak brightness in less than 53 hours and faded back to half that brightness in 6.8 days.

Often, quick supernovae are dimmer than their longer-lasting counterparts, so they can be explained simply by invoking a weaker mechanism like a star that only partially exploded. But this one, called KSN 2015K, was just about as bright as a regular supernova, so it needed a different explanation.

Rest and his colleagues were able to take images of the supernova once every 30 minutes, making it the most thoroughly observed of the fast supernovae. "Usually you might have 1 or 2, maybe 3 measurements in 2.2 days, but we have a whole series of really strong measurements that allow us to test different models," says Rest.