Last fall, a little-known star called KIC 8462852 became our planetary obsession when astronomers said that its erratic flickering could be the result of an alien megastructure. Further observation of Tabby's Star yielded no signs of aliens, but the sudden dips in luminosity continue to defy explanation. Now, things just got a bit weirder.

In an unpublished paper posted today to arXiv, Caltech astronomer Ben Montet and Joshua Simon of the Carnegie Institute describe the results of a new photometric analysis of Tabby's Star, which was first flagged in the Kepler Space Telescope's database by citizen science astronomers.

By carefully examining all the full-frame images collected during Kepler's observational campaign, Montet and Simon discovered something astonishing: Not only did the star's light output occasionally dip by up to 20 percent, its total stellar flux diminished continuously over the course of four years.

For the first 1000 days of Kepler's campaign, Tabby's Star decreased in luminosity by approximately 0.34 percent per year. For the next 200 days, the star dimmed more rapidly, its total stellar flux dropping by 2 percent before leveling off. Overall, Tabby's Star faded roughly 3 percent during the four years that Kepler stared at it—an absolutely enormous, inexplicable amount. The astronomers looked at 500 other stars in the vicinity, and saw nothing else like it.

"The part that really surprised me was just how rapid and non-linear it was," Montet told Gizmodo. "We spent a long time trying to convince ourselves this wasn't real. We just weren't able to."

This gigantic nuclear explosion-style mushroom cloud looming over a Russian city certainly gave residents a fright.

The bizarre phenomenon was dubbed 'Chernobyl Sky' by shocked residents, in reference to the 1986 nuclear catastrophe in Ukraine.

The frightening but harmless cloud over Tyumen, in south central Russia, was later blown off by the wind.

One social media user wrote: "Chernobyl-style sky... Crazy. Like a nuclear explosion happened there or something. Sky was unreal."

Like an approaching UFO, the bright white luminous ball glides over a field, before heading into woodland.

A local caught on camera this unusual example of ball lightning near his dacha (country house) outside Novosibirsk, Siberia's largest city. His grasp of his cell phone was shaky but his analysis of the phenomenon - as heard on the commentary - was accurate, say experts.

'What is it there?' a female voice asks from a distance.

'Fireball lightening,' answered the man with the mobile phone camera, Roman Tregubov, a graduate of the Novosibirsk State Technical University.

'Look, look, what is it?' another man asks.

'Argh it's moving away,' the cameraman says. 'This is fireball lightening, it's the first time I see one in my life. It's going to move away. Lost it. Where it is? There is it. I wonder if it'll blow off soon. Yep, it blew off.'

Thirty years ago, a star that went by the designation of SN 1987A collapsed spectacularly, creating a supernova that was visible from Earth. This was the largest supernova to be visible to the naked eye since Kepler's Supernova in 1604. Today, this supernova remnant (which is located approximately 168,000 light-years away) is being used by astronomers in the Australian Outback to help refine our understanding of stellar explosions.

Led by a student from the University of Sydney, this international research team is observing the remnant at the lowest-ever radio frequencies. Previously, astronomers knew much about the star's immediate past by studying the effect the star's collapse had on the neighboring Large Magellanic Cloud. But by detecting the star's faintest hisses of radio static, the team was able to observe a great deal more of its history.

The team's findings, which were published yesterday in the journal Monthly Notices of the Royal Astronomical Society, detail how the astronomers were able to look millions of years farther back in time. Prior to this, astronomers could only observe a tiny fraction of the star's life cycle before it exploded - 20,000 years (or 0.1%) of its multi-million year life span.

As such, they were only able to see the star when it was in its final, blue supergiant phase. But with the help of the Murchison Widefield Array (MWA) - a low-frequency radio telescope located at the Murchison Radio-astronomy Observatory (MRO) in the West Australian desert - the radio astronomers were able to see all the way back to when the star was still in its long-lasting red supergiant phase.

I don't know about you, but I've always secretly wanted to serendipitously discover something incredible in one of my lab courses. Well, some students in Japan got to experience just that. A group of astronomers and undergraduate students at the National Astronomical Observatory of Japan (NAOJ) in Tokyo found a unique galaxy system they dubbed the Eye of Horus.

Masayuki Tanaka (NAOJ) and several students were looking at images taken with the Hyper Suprime-Cam at the Subaru telescope when they found the odd-looking system.

Once Tanaka saw the warped light, he immediately recognized it as a strong gravitational lens — where a galaxy's gravity bends the light from a background galaxy. Strong lensing helps probe the distribution of matter around galaxies.

A closer look at the images showed one reddish ring and another with a blue tint. The two colors suggested that not just one but two galaxies were being lensed, something that's rarely observed. There are only a handful of systems like this currently known, but the distant galaxies haven't been measured because they're too faint.

Based on data from the Sloan Digital Sky Survey, light from the lensing galaxy takes 7 billion years to arrive at Earth. Astronomers conducted follow-up observations on the Magellan Telescope and confirmed that light from the background galaxies take 9 and 10.5 billion years, respectively. The data confirm that there are two galaxies at two different distances. They also show that one of the galaxies seems to be made of two distinct clumps, according to Kenneth Wong (NAOJ), which could indicate a pair of interacting galaxies.

With 300 nights of data, the Hyper-Suprime Cam's survey is the largest observing program ever approved at the Subaru Telescope. The survey, still in its early phases, hopes to address outstanding astrophysics questions about the nature of dark energy, how galaxies evolve, and when galaxies first started pumping out stars. The team expects to find about 10 more double-lensed galaxies in the survey.

The paper on the discovery was published in the July 25th issue of Astrophysical Journal Letters.

Most of us would probably call them "rainbow clouds." To meteorologists, their name is a much more technical "circumhorizontal arc." Whatever you call them, they are a cool sight to see, and fairly rare features in the skies over South Jersey.

A rainbow forms when sunlight passes through a raindrop, and the light is refracted to form the multiple colors of the rainbow. Rainbows are best seen when the sun is lower in the sky, let's say the morning or evening hours. When the sun is higher in the sky during the midday hours, the rainbow will still form, but it will be below the horizon and unable to be seen.

Circumhorizontal arcs form the same way. Sunlight passes through plate-shaped ice crystals in high altitude cirrus clouds, causing a partial arc or rainbow. However, the sun must be high in the sky in order to create the arc. That means these rainbow-like clouds will only be seen during the middle part of the day, when the sun angle is the highest.

The light of the full moon can also cause the same effect, but the rainbow colors are naturally more difficult to see at night.

The summer sun and just a hint of high clouds combined for quite the show up along Mt. Rainier Tuesday.

Jason Shipley with Uniquely Northwest Photography was driving near Mt. Rainier National Park when he spotted this "fire rainbow" (official name: Circumhorizontal arc) hovering in the sky, and had to pull over to snap a couple of photos:

But he says just as quick as it appeared, it disappeared. That's because to get this somewhat-rare phenomenon, the sun has to be higher than 58 degrees altitude in the sky -- which only happens just around midday in the summertime in the Seattle area. Then you have to have the right shaped ice crystal in the cloud aligned at just the perfect angle to the sunlight for the refraction effect to work.


It's the second time the fire rainbows have put on a show (that we've seen) this summer. Find more photos and an extended explanation in this earlier blog entry.

A rare cloud formation, often called the morning glory, has rolled across outback Queensland delighting locals.

Michael Butler was home at Athol station, Blackall, on Saturday morning when he looked up and saw the cloud rolling across the sky.

The morning glory is often seen in the Gulf of Carpentaria in September but is almost never sighted over inland areas.

Mr Butler said in 16 years on his Blackall property, he had never witnessed anything like it.

"You see some unusual clouds in the storm season with the cold fronts but nothing like that," he said.

"This was just unusual, for being such a beautiful day, and this cloud just coming out of nowhere.

Astronomers using ESO's Very Large Telescope, along with other telescopes on the ground and in space, have discovered a new type of exotic binary star. In the system AR Scorpii a rapidly spinning white dwarf star powers electrons up to almost the speed of light. These high energy particles release blasts of radiation that lash the companion red dwarf star, and cause the entire system to pulse dramatically every 1.97 minutes with radiation ranging from the ultraviolet to radio. The research will be published in the journal Nature on 28 July 2016.
In May 2015, a group of amateur astronomers from Germany, Belgium and the UK came across a star system that was exhibiting behaviour unlike anything they had ever encountered. Follow-up observations led by the University of Warwick and using a multitude of telescopes on the ground and in space [1], have now revealed the true nature of this previously misidentified system.

The star system AR Scorpii, or AR Sco for short, lies in the constellation of Scorpius, 380 light-years from Earth. It comprises a rapidly spinning white dwarf [2], the size of Earth but containing 200 000 times more mass, and a cool red dwarf companion one third the mass of the Sun [3], orbiting one another every 3.6 hours in a cosmic dance as regular as clockwork.

In a unique twist, this binary star system is exhibiting some brutal behaviour. Highly magnetic and spinning rapidly, AR Sco's white dwarf accelerates electrons up to almost the speed of light. As these high energy particles whip through space, they release radiation in a lighthouse-like beam which lashes across the face of the cool red dwarf star, causing the entire system to brighten and fade dramatically every 1.97 minutes. These powerful pulses include radiation at radio frequencies, which has never been detected before from a white dwarf system.

A young star cluster surrounded by three concentric bubbles was recently found near the M33 galaxy, revealing a cosmic splendor that could be compared to Russian matryoshka nesting dolls.

The concentric bubbles, which comprise what researchers call a triple-bubble, are actually three supernova remnants, shells of gas and dust that form following the explosion of a star. This is the first known case of three supernova remnants nesting one inside the other, said the researchers from the Institute of Astrophysics of the Canary Islands (IAC), who made the discovery. The above illustration shows what a cross section of the three rings might look like if scientists could get a closer look.

The shells provide a unique opportunity to study the remains of these stellar explosions, as well as the the interstellar medium, which is the gas and dust that lies between stars, John Beckman, co-author of the new study, said in a news release. Beckman is an astrophysicist with the Spanish National Resource Council and IAC. "We can measure how much matter there is in a shell, approximately a couple of hundred times the mass of the sun in each of the shells," he said.

Using the high-resolution 2D spectrograph GHaFaS (Galaxy Halpha Fabry-Perot System), mounted on the William Herschel Telescope in Spain's Canary Islands, the researchers examined the complex structure of this triple-bubble. The work revealed that the three shells all formed chronologically in the same way, from separate supernova explosions within the same star cluster, Beckman said.