Tag Archives: red

How on Earth did we start using “once in a blue moon”?

You’ve heard it, I’ve heard it, but not many people we know have actually seen a blue moon — so what gives?

Am image of the moon captured through a blue filter.
Image credits steviep187 / Flickr.

“Once in a blue moon” refers to events that only happen very rarely, but it’s a tricky idiom. It doesn’t refer to a moon that’s actually blue, although it can appear to be that color under certain conditions and that probably shaped the saying.

A blue moon is a real occurrence and, you might be surprised to hear, isn’t actually that rare or unpredictable. Blue moons are ‘extra’ full moons of the regular gray color that pop up every two or three years due to misalignment in the lunar and solar circle. But the phrase was first used to refer to something being absurd — like someone arguing that the moon is blue.

So let’s take a look at both halves of this idiom and see why they came to represent the quintessential rare occurrence.

The literal blue moon

Image credits Bobby Jones.

The moon can naturally appear blue or light-blue in the sky. It’s a rare event caused by the presence of dust or smoke particles in the atmosphere at night which alter the way light is diffracted in the atmosphere. If these particles are of the right size, they can scatter the red part of the light spectrum, leaving the rest untouched.

Because visible light spans from red (low-energy) to blue (high-energy), this scattering makes everything take on a blue tint. Since the moon is a white-ish gray on a dark background, this effect causes it to look blue.

This type of blue moon is probably what spawned the idiom. It’s very rare and very unpredictable, as its appearance relies directly on phenomena such as massive wildfires or volcanic eruptions. The fact that it’s entirely dependent on local phenomena also means blue moons are only visible from relatively small areas at a time, not globally — which compounds their rarity.

Some events that led to blue moons include forest fires in Canada, and the eruptions of Mount St. Helens in 1980 and the El Chichón volcano in Mexico in 1983. The eruption of Krakatoa in 1883 (one of the largest in history) reportedly caused blue moons for nearly two years.

A pretty exciting implication of the mechanism that spawns blue moons is a purple sun. In 1950, as huge fires swept the bogs of Alberta, Canada billowing with smoke, leading to sightings of blue moons from the US to England the following night. Two days later, reports of an indigo sun peering through the smoky skies also started to surface.

File:Blood moon 73.jpg
A blood moon.
Image credits Andrey73RUS / Wikimedia.

So why don’t all volcanic eruptions and wildfires turn the moon blue? Well, the size of ash or oil/tar particles they generate is very important. These have to be wider than the wavelength of red light, which is 0.7 micrometers, to block these rays. At the same time, very few to no particles of smaller sizes should be present, as these would help scatter other colors and destroy the overall effect.

Naturally-occurring ash tends to be a mix of particles of various sizes, with most being smaller than the above threshold. Since smaller particles preferentially scatter (i.e. remove) light towards the high end of the spectrum (blue), natural ash clouds typically give everything a shade of red. Red or blood moons are thus a much more common occurrence than blue moons.

The figurative blue moon

Traditionally a blue moon is an additional full moon that appears every 2 and a half years or so, according to NASA. In recent times it has also come to denote the second full moon to appear within a single calendar month in popular use.

This stems from the way lunar and solar cycles relate to one another. There are 29.5 days between full moons, the agency goes on to explain, so each year will have roughly 12.3 full moons. Another implication of this is that 28-days-long February can’t ever have a blue moon.

Both uses of the phrase are considered valid today.

Over time, the idiom turned from meaning that something is impossible to “never” — think along the lines of “I’ll help you when the pigs fly”.

“The definition of a Blue Moon [as] ‘the second full moon in a calendar month,’ is a curious bit of modern folklore. How it emerged is a long story involving old almanacs, a mistake in Sky and Telescope magazine, and the board game Trivial Pursuit,” wrote Dr. Tony Phillips for NASA.

One of the almanacs Dr. Phillips mentions is the Maine Farmer’s Almanac, more specifically its August 1937 issue. The publication followed certain conventions about how to name each moon depending on the time of year. The first full moon of spring for example was called the Egg Moon, Easter Moon, or Paschal Moon, and had to fall within the week before Easter. If a particular season had four moons, the extra one was called a Blue Moon to maintain the naming conventions.

The definition of the blue moon as being the second full month in a single month came, according to Space, from a mistaken interpretation of the term which was popularized by a nationally syndicated radio program in 1980.

Rarer than Blue Moons are double Blue Moons — when the same calendar year gets two of these events. They’re much rarer, only occurring about 3-5 times every hundred years or so; the next double blue moons are expected in 2037. As for a single blue moon, the next one is expected on October 31, 2020.

Planets transiting.

NASA finds new exoplanet that orbits three different suns

Researchers report finding a new exoplanet orbiting a three-star system.

Planets transiting.

Artist’s view of planets transiting red dwarf star in TRAPPIST-1 system.
Image credits Hubble ESA / Flickr.

The excitingly-named LTT 1445Ab orbits one star from a group of three red dwarves that constitute the system LTT 1445, located around 22.5 light-years away. While definitely rocky in nature, high surface temperatures on LTT 1445Ab make it completely unwelcoming for life as we know it. However, researchers are still excited for the find — its atmosphere makes it a perfect test subject to help us refine our long-distance planetary analysis techniques.

LTT 1445Ab and the three red dwarves

“If you’re standing on the surface of that planet, there are three suns in the sky, but two of them are pretty far away and small-looking,” Jennifer Winters, an astronomer at the Harvard-Smithsonian Center for Astrophysics and the paper’s first author told New Scientist.

“They’re like two red, ominous eyes in the sky.”

Stars in multiple-star systems are gravitationally locked around a mutual center of gravity, which they all orbit. LTT 1445 is home to three such stars. The new exoplanet was discovered in this system by the Transiting Exoplanet Survey Satellite (TESS), NASA’s planet-hunting space telescope. TESS was designed to spot exoplanets as they pass between Earth and their home star by detecting the slight dimming the planet causes as it blocks part of the star’s light.

Based on the amount of dimming and on the tiny, almost imperceptible, movements stars make under the effect of an orbiting planet’s gravity (in the case of LTT 1445Ab this was measured with other telescopes than TESS), researchers can estimate the size and mass of the planet. The new planet is about 1.35 times the physical size of Earth but it packs up to 8.4 times Earth’s mass, so it’s a lot denser than our home planet.

Judging by its size and mass, this is definitely a rocky planet — like Earth, Venus, or Mars — not an ice or gas giant. However, don’t break out your colonizing gear just yet. The planet is so close to its host star that it only has a 5.36 day-long orbit. At this distance, surface temperatures likely hover around 428 Kelvin (155 °C; 311 °F), the authors report.

While LTT 1445Ab won’t be a welcoming home for us anytime soon, it’s still an exciting planet for astronomers because it might have an atmosphere. Rocky planets with atmospheres that transit in front of their stars are good test subjects for the detection tools we use to spot gases such as methane and carbon dioxide on alien worlds. Such a planet won’t just dim a star’s light as it transited in front of it but, based on the atmosphere’s chemical composition, would also change the properties of the light.

By analyzing at this change, researchers can estimate the chemical make-up of an alien world’s atmosphere. Our current technology and know-how in this field can still use some tweaking, one which LTT 1445Ab can help provide. With Hubble’s successor, the James Webb Space Telescope due to be launched in 2021, astronomers are already making a list of targets they’d like it to study. LTT 1445Ab could be a perfect candidate.

Among the properties that recommend it for this role is that it transits in front of its star very often, meaning the James Webb Space Telescope can take many readings in a short span of time. The planet is also relatively close in astronomical terms, which makes it easier to take high-quality images, and its red dwarf star is just right for this kind of observation — bright enough to back-light the atmosphere, but not so bright that the planet is hard to see.

Mind you, we don’t know whether LTT 1445Ab has an atmosphere or not right now. But even if it doesn’t, or if its atmosphere contains no biosignatures, it could tell us more about what we can expect to find on rocky planets that orbit red dwarfs.

The paper “Three Red Suns in the Sky: A Transiting, Terrestrial Planet in a Triple M Dwarf System at 6.9 Parsecs” has been submitted to the The Astronomical Journal and is available on the preprint server arXiv.

Tanzania’s blood-red lake snapped from space by NASA

On March 6, 2017, NASA’s Landsat 8 satellite swooped over Tanzania and snapped some incredible pictures of its ruby-red lake.

Lake Natron.

Click for full resolution.
Image credits NASA Earth Observatory.

Northern Tanzania is home to a beautiful, bloody-crimson body of water known as Lake Natron. Apart from its striking hue, the water also has a high concentration of natural salts, making it very alkaline, up to 10.5 on the pH scale.

So what makes a lake turn ruby-red and almost as caustic as ammonia? Well, it all comes down to the area’s geology, particularly its volcanism. The lake sits about 20km north of Ol Doinyo Lengai, an active volcano that juts out of the surrounding plain. Ol Doinyo Lengai is the only volcano known to have ever released carbonatite lava (poor in silica, rich in carbonate minerals) in human history, which is more chemically similar to sedimentary rocks than other types of lava (which are predominantly silica).

Its products flow, fall, roll, and push through faults all the way to the lake, enriching it in alkaline salts and other material. Waterwise, Lake Natron is chiefly supplied by the Southern Ewaso Ng’iro River and mineral-rich hot springs that are powered by Ol Doinyo’s volcanism. Minerals and salts released by this process, particularly sodium carbonate, push the waters of Lake Natron even higher beyond water’s neutral 7 point mark on the pH scale.

Detail of the lake.
Image modified after NASA Earth Observatory.

These conditions are ripe for holoarchaea, a class of microorganisms which thrives in salty environments. As they multiply, the holoarchaea lend the water its red hue — the rainy seasons in the area runs from March to May and at the time Landsat passed over Lake Natron, the water level was particularly low and the salt ponds were very colorful.

Most animals (us too) can’t handle water as alkaline and salty as this, but Lake Natron is home to a few species which have adapted to withstand the harsh chemical conditions. Flocks of birds often camp on its shores, and tilapia fish brave its briny waters. Flamingos, in particular, favor the area as a nesting site during the dry season, since moat-like channels and the harsh waters make an ideal fortification against predators.

Lake Natron detail.

Image credits NASA Earth Observatory.

The climate here is arid. In a non-El Niño year, the lake receives less than 500 millimeters (20 inches) of rain. Evaporation usually exceeds that amount, so the lake relies on other sources—such as the Ewaso Ng’iro River at the north end—to maintain a supply of water through the dry season.

But it’s the region’s volcanism that leads to the lake’s unusual chemistry. Volcanoes, such as Ol Doinyo Lengai (about 20 kilometers to the south), produce molten mixtures of sodium carbonate and calcium carbonate salts. The mixture moves through the ground via a system of faults and wells up in more than 20 hot springs that ultimately empty into the lake. The lake, however, can be a double-edged sword — as this flamingo can attest.

Red blood cells.

Immortal cells could usher in the age of plentiful, artificial blood for transfusions

Immortalized cell lines could one day be used to create an endless supply of blood for medical uses. A new paper reports the first successful use of such an immortalized line to synthesize blood.

Red blood cells.

Image credits Gerd Altmann.

Blood is really important if you plan on staying alive. But it does have an annoying habit of flowing out and away from pokes and scratches in your body, or during surgery and other medical procedures — so doctors need to have a steady supply on hand at all times to replenish the losses.

Trouble is, doctors today rely on donors to keep stocks of blood up, and there are way more patients than donors. Not only that, they also need to match the blood type of the patient with the donor and make sure they have the right volume of blood. So overall, it can get pretty nerve-racking for doctors to make sure they have enough healthy blood of the right type available when they need it.

Blood on tap

But the life of doctors (and probably vampires) is about to get a whole lot better as a group of scientists at the University of Bristol, along with colleagues from the NHS Blood and Transplant, developed a method that should allow us to produce a virtually endless supply of high-quality artificial blood.

The breakthrough would allow for a steady supply of red blood cells to be produced, which could then be used to create artificial blood for transfusions. There are a number of techniques available today to do just that, but they’re very limited in the amount of cells they can produce. For example, certain types of stem cells can be used to produce red blood cells, but the generating sample dies off after producing about 50.000 cells — but a typical bag of blood contains somewhere around 1 million such cells.

The solution, the team says, is immortalizing the generating cell line, so they will never die off and keep making red blood cells. One such cell line has been pioneered by UoB researchers, and they named it the BEL-A (Bristol Erythroid Line Adult). The secret to their success is that they immortalized the stem cells in their premature stage. The cells can then be mobilized to divide and produce red blood cells. It’s the first known line of cells which can continuously produce red blood cells and also generate additional lines successfully.

“Cultured red blood cells provide such an alternative and have potential advantages over donor blood, such as a reduced risk of infectious disease transmission, and as the cells are all nascent, the volume and number of transfusions administered to patients requiring regular transfusions (sickle cell disease, thalassaemia myelodysplasia, certain cancers) could be reduced, ameliorating the consequences of organ damage from iron overload” the paper reads.

Their use could allow a constant supply of blood even in hospitals situated in remote and isolated areas, making a huge difference in life-or-death scenarios where doctors won’t have to wait on a shipment of blood to arrive. Another huge implication of the BEL-A cells is that they could finally decouple the patients from donors, meaning people with rare blood types won’t lack for blood due to a shortage in donors with the same blood type.

The researchers say that in addition to its role in supplying blood, BEL-A cells can also prove to be a powerful tool in further research. Right now, the technique is awaiting clinical trials.

The paper “An immortalized adult human erythroid line facilitates sustainable and scalable generation of functional red cells” has been published in the journal Nature Communications.


This dusty, iron-rich surface gives Mars its famous red. Beneath the dusty surface, which is anywhere between a few millimetres and two metres deep, we can find hardened lava composed mostly of basalt. Credit: NASA

Why is Mars red?

mars rotating gif

Credit: Giphy

Mars is often called the ‘Red Planet’ for obvious reasons. But what gives our neighboring planet this distinct hue? While Earth is sometimes referred to as the ‘blue marble’ because it’s mostly covered in oceans and has a thick atmosphere, giving it a blue appearance, Mars is covered in a lot of iron oxide — these are the same compounds that give blood and rust their distinct color. In light of this, it’s no coincidence that Mars, which occasionally appears as a bright red ‘star’, was named after the Greek god of war.

This dusty, iron-rich surface gives Mars its famous red. Beneath the dusty surface, which is anywhere between a few millimetres and two metres deep, we can find hardened lava composed mostly of basalt. Credit: NASA

Its dusty, iron-rich surface gives Mars its famous red color. Beneath the dusty surface, which is anywhere between a few millimeters and two meters deep, there is hardened lava composed mostly of basalt. Credit: NASA

It’s not entirely clear how all that iron oxide wound up on the planet’s surface, but we do know that the planet formed some 4.5 billion years ago when debris, gas, and dust began coalescing. Among these materials was a lot of iron that was forged in the heart of long-dead stars.

Earth and Mars both have a lot of iron, but while the heavy elements sank to Earth’s core when the planet was still young and mushy, scientists think iron was less homogeneously incorporated into Mars due to its weaker gravity and smaller size. That’s not to say Mars doesn’t have an iron core as well, but there’s still a lot of the metal in the upper crust to be found.

Yet, iron by itself isn’t red — its color usually ranges from. What happened is that all of this surface iron became oxidized, forming iron oxide known more commonly as rust — a compound made of two iron atoms and three oxygen atoms. But why did so much of Mars’ surface iron get oxidized? Scientists aren’t sure, but there’s reason to believe this massive oxidation happened when Mars had flowing water and a thick atmosphere — possibly not too different from modern day Earth. Leaving an iron-rich pot or spoon outside or in water for a long time will make it rust. A very similar process covered Mars in iron oxide.

An alternate theory, first proposed by Albert Yen of NASA’s Jet Propulsion Laboratory and based on data gathered by the 1997 Pathfinder mission, says a great deal of that iron oxide comes from meteorites.

In 2009, Danish researchers performed a study which found water isn’t necessary to produce a lot of iron oxide. Instead, crumbling quartz crystals — the kind found in the Martian regolith — leaves oxygen-rich surfaces exposed. This could easily have happened during Martian dust storms, which are so intense that the dust they kick up can be seen with telescopes on Earth. Sunlight can also break down carbon dioxide and other molecules from the atmosphere, producing oxidants like hydrogen peroxide and ozone.

This view from the Mast Camera (Mastcam) in NASA’s Curiosity Mars rover shows an outcrop of finely layered rocks within the Murray Buttes region on lower Mount Sharp. Image credits NASA/JPL-Caltech.

This view from the Mast Camera (Mastcam) in NASA’s Curiosity Mars rover shows an outcrop of finely layered rocks within the Murray Buttes region on lower Mount Sharp. Image credits NASA/JPL-Caltech.

However, the entire planet is not red. Some regions look bright red, while others will appear black because not everything is covered in iron oxide dust. Thanks to the rovers NASA has landed on the planet, like Opportunity, Spirit, and Curiosity (the latest to touch down), we now have unprecedented images of just of Mars’ surface, but also of its subsurface. When the Phoenix Lander drilled just a few centimeters below the iron oxide rich surface, the ground was brown.

The sky on Mars is red, too

Mars sky

An exaggerated color image mosaic of images from NASA’s Mars Rover Opportunity. The clouds can be composed of ice made from either carbon dioxide or water and can move swiftly across the sky. (NASA/JPL/Cornell)

Earth’s sky appears blue because of a physical phenomenon called Rayleigh scattering. Because shorter wavelengths of light, like violet and blue, are scattered more by the molecules in the atmosphere, the blue photons appear to come from all directions. On Mars, the opposite is true because the dust that litters the planet’s light atmosphere scatters red photons, making the sky appear red. This can also happen on Earth when the air is heavily polluted or covered in smoke.

Oddly enough, sunsets on Mars appear blue.

On May 19, 2005, NASA's Mars Exploration Rover Spirit captured this stunning view as the Sun sank below the rim of Gusev crater on Mars. This Panoramic Camera mosaic was taken around 6:07 in the evening of the rover's 489th Martian day, or sol. Credit: Image Credit: NASA/JPL/Texas A&M/Cornell

On May 19, 2005, NASA’s Mars Exploration Rover Spirit captured this stunning view as the Sun sank below the rim of Gusev crater on Mars. This Panoramic Camera mosaic was taken around 6:07 in the evening of the rover’s 489th Martian day, or sol. The colors are slightly exaggerated. Credit: Image Credit: NASA/JPL/Texas A&M/Cornell

Scientists may have seen a black hole being born for the first time ever

Scientists think they spotted the first-ever glimpse of how black holes form from a former supernova 20 million light-years away.

The Gargantua black hole from Interstellar.
Image credits Double Negative

When massive stars grow old and start running short on fuel, they explode in a dazzling display of light — a supernova. Huge quantities of matter and radiation are shot out at incredible speeds, squishing the core into something so dense that not even light can escape its gravitational pull — a leftover we call a black hole.

That’s what we think happens, anyway — we’ve never actually seen it per se. But now, an Ohio State University of Columbus team led by Christopher Kochanek might have witnessed it. They were combing through data from the Hubble Space Telescope when they observed something strange with the red supergiant star N6946-BH1.

Crunch time

The star was discovered in 2004 and was estimated to be roughly 25 times as massive as the Sun. But when Kochanek and his team looked at snaps taken in 2009, they found that the star flared a to a few million times the brightness of our star for a few months then slowly started to fade away. On the photos Hubble took in the visible spectrum, the star had all but disappeared — the only trace left of its presence is a faint infrared signature.

What happened to N6946-BH1 fits in nicely with what our theories predict should happen when a star its size collapses into a black hole. When it runs out of fuel, the star releases an immense number of neutrinos, so many that it starts losing mass. This in turn weakens its gravitational field, so it starts losing its grip on the cloud of super-heated hydrogen ions enveloping it. As the gas floats away it cools off enough for electrons to re-attach to the hydrogen nuclei.

Now, a star is basically an explosion so massive it keeps itself together under its own weight. Gravity on one hand tries to crunch everything into a point, while the pressure generated by fusion inside the star pushes it outward. While these two are in balance, the star burns away merrily. But once it starts running out of fuel, gravity wins and draws everything together. Matter sinks in the core making it so dense that it collapses in on itself, forming a black hole.

Ironically, it’s gravity that makes stars explode into supernovas — the outer layers are drawn towards the core at such speeds that they bounce off, compacting the core even further. N6946-BH1 didn’t make it to a supernova, but its core did collapse into a black hole. The team theorizes that the flaring we’ve seen is caused by super-heated gas forming an accretion disk around the singularity.

“The event is consistent with the ejection of the envelope of a red supergiant in a failed supernova and the late-time emission could be powered by fallback accretion onto a newly-formed black hole,” the authors write.

We’re still looking for answers

There are two other ways to explain a vanishing star, but they don’t really stand up to scrutiny. N6946-BH1 could have merged with another star — but it should have burned even brighter than before and for longer than a few months — or it could be enveloped in a dust cloud — but it wouldn’t have hidden it for so long.

“It’s an exciting result and long anticipated,” says Stan Woosley at Lick Observatory in California.

“This may be the first direct clue to how the collapse of a star can lead to the formation of a black hole,” says Avi Loeb at Harvard University.

Thankfully, confirming whether or not we’re looking at a black hole isn’t very difficult. The gasses that make up the accretion disk should emit a specific spectrum of X-rays as its being pulled into the black hole, which we can pick up. Kochanek says his group will be getting new data from Chandra X-Ray Observatory sometime in the next two months.

So is this a black hole? Even if they don’t pick up on any X-rays, the team says it doesn’t rule out such an object and that they will continue to look through Hubble – the longer the star is not there, the more likely that it’s a black hole.

“I’m not quite at ‘I’d bet my life on it’ yet,” Kochanek says, “but I’m willing to go for your life.”

The full paper titled “The search for failed supernovae with the Large Binocular Telescope: confirmation of a disappearing star” is still awaiting peer review, and has been published online on arXiv.

The colour red increases speed and strength of reactions

What can possibly link together speed, strength, and the colour red ? Nope, it’s not a brand new Ferrari – it’s your muscles ! A new groundbreaking study published in the journal Emotion shows that if you see red, your reactions become faster, more powerful, and you won’t even realize it.

Science and sports

Of course, due to the crazy amounts of money that are put in sports these days, one of the first thing that comes to mind is using this advantage to become a better athlete. A brief burst of speed and strength is often all you need to overcome your competition, but scientists warn that the ‘colour energy’ is likely short lived.

“Red enhances our physical reactions because it is seen as a danger cue,” explains coauthor Andrew Elliot, professor of psychology at the University of Rochester and a lead researcher in the field of color psychology. “Humans flush when they are angry or preparing for attack,” he explains. “People are acutely aware of such reddening in others and it’s implications.”

But a threat is a double edged sword, Elliot and coauthor Henk Aarts, professor of psychology at Utrecht University, in the Netherlands argue. Along with the increased qualities, side effects also include “worry, task distraction, and self-preoccupation, all of which have been shown to tax mental resources”.

Good for reactions, bad for your mind

Red has already been proven as counter productive for sustained mental activities, such as studying, for example; it has been shown that students exposed to red before an exam fare slightly worse than those who weren’t.

“Color affects us in many ways depending on the context,” explains Elliot, whose research also has documented how men and women are unconsciously attracted to the opposite sex when they wear red. “Those color effects fly under our awareness radar,” he says.

Testing students’ reactions

The study was conducted by measuring the reactions of students in two experiments.

In the first one, students from 4th to 10th grade pinched and held open a metal clasp. Right before doing so, they read aloud their participant number written in either red or gray crayon.

In the second experiment, undergrads were asked to squeeze a handgrip with their dominant hand as hard as possible when they read the word squeeze on a screen. The word appeared on a blue, gray, and red background.

In both scenarios, red increased the strength significantly, and in the second experiment, it was proven that not only the power, but also the reaction speed was increased. The colours in the experiment were also exactly controled, in terms of hue, brightness, and chroma (intensity) to insure that reactions were not a result of some other variable besides colour.

“Many color psychology studies in the past have failed to account for these independent variables, so the results have been ambiguous,” explains Elliot.

If you ask me, it’s another great example of how the most mundane elements around us, like colour, can have a significant impact on our lives. Hopefully, studies will be continued in this direction so that there will be even a vague method of quantification.

Picture sources: 1 2

The best view so far of the Jupiter red spot

I’ve seen a whole lot of pictures of the red giant spot (it’s about as big as Earth), but this one is by far the best one so far; and it’s been posted by an amateur astronomer, Björn Jónsson, on one of my favorite forums: unmannedspaceflight – lots of great pics and discussions there. Well basically he just processed some pictures taken more than 30 years ago, in 1979.

“This is a 4×3 mosaic of images. The processing is almost identical to the processing described in the first message of this thread so I’m not decribing it further here. One caveat though: There is probably some slight geometric distortion but it shouldn’t be a problem in this case. The images I used were obtained on March 4,1979 at a distance of about 1.85 million km. The first image (C1635314.IMQ) was obtained at 07:08:36 and the last one (C1635400.IMQ) at 07:45:24. The resolution is roughly 18 km/pixel.”, said Mr. Jónsson in his post.

My new mosaic reveals an enormous amount of details, especially in the sharpened version. Some of these details I didn’t know were visible in any images of Jupiter until relatively recently. The sunlight is coming form the east (right) and because the GRS is in the southern hemisphere it’s really coming roughly from the ENE over the GRS and the regions south of it. With this in mind, vertical relief and cloud shadows are clearly visible at many locations around the GRS’ periphery.