The Moon, still young after all these years / See a Callisto eclipse!

The Moon and Mars gather in the west at dusk this evening. Stellarium

Tonight the returning young crescent Moon puts down stakes near the planet Mars in Sagittarius. Look for the pair low in the southwestern sky at dusk.

We’re used to hearing how ancient the Moon is. Its origin goes back to 4.48 billion years ago when a Mars-sized planet sideswiped the Earth, blasting debris into space that quickly coalesced into our satellite. While it’s true that most of the Moon’s crust and craters date from then, recent close-up photos from NASA’s Lunar Reconnaissance Orbiter (LRO) suggest the Moon remained volcanically active until not that very long ago. At least on geological time scales.

Ina Caldera, a classic IMP, sits atop a low, broad volcanic dome or shield volcano, where lava once oozed from the moon’s crust. The darker patches in the photo are blobs of older lunar crust. They  form a series of low mounds higher than the younger, jumbled terrain around them. Credit: NASA

100 million years ago, when dinosaurs cracked jokes about the early mammals, lava oozed from cracks in the Moon’s crust to create what astronomers nowadays call IMPs or Irregular Mare Patches. They’re characterized by a mixture of smooth, shallow mounds next to patches of rough, blocky terrain. Only one, called Ina, is large enough to see in amateur telescopes. The others, liberally sprinkled across the lunar nearside, are generally less than 1/3 mile (500 m) across. Using the LRO, a team of researchers led by Sarah Braden of Arizona State University has found 70 landscapes similar to Ina.

When it comes to the big picture, 100 million years is a small slice of Earth’s history. Credit: NASA

Maria (plural of “mare”) are those big dark spots the make up the face of the man in the moon. They’re actually huge expanses of lava that welled up from cracks in the Moon’s crust several billion years ago after asteroid impacts. IMPs are much more recent. Some may be as “young” as 50 million years old. This was well after the dinosaurs succumbed to major climate changes induced by the impact of a 6-mile-wide asteroid hit here on Earth. Now the mammals are cracking jokes about the dinos.

A selection of some of the 70 IMPs discovered during the survey. Credit: NASA

“Discovering new features on the lunar surface was thrilling!” says Braden. “We looked at hundreds of high-resolution images, and when I found a new IMP it was always the highlight of my day.”

Astronomers determine ages of lunar features by doing crater counts. The more lightly cratered an area is, the younger.

Here’s the scene tomorrow morning November 26th with all four of Jupiter’s bright moons. Callisto, which sits right next to Europa, will dramatically fade over several minutes time starting about 4:50 a.m. CST. Meanwhile, 15 minutes later at 5:05 a.m., Ganymede will exit its eclipse and return to view. Add one hour for EST, subtract an hour for MST and two hours for PDT. South is up. Stellarium

Some of you may be early morning observers. Well, I’ve got a special event to share with you. Tomorrow morning November 26th, Jupiter’s bright moon Callisto will be eclipsed by Jupiter’s shadow starting at 4:50 a.m. (CST) and disappear for nearly five hours.

Just 15 minutes after Callisto disappears, Ganymede emerges from eclipse at 5:05 a.m. (CST). One disappears, the other reappears. Pretty cool! Jupiter will be the brightest thing in the sky high in the south in Leo at the time. You can always find out what Jupiter’s moons anytime of day or night by visiting Sky and Telescope’s Jupiter’s Moons site.

Lively Leonid meteor shower peaks tomorrow, Tuesday

The annual Leonids peak this week. About a dozen per hour will be visible from a dark site. The shower’s known for fireballs that often leave persistant “smoke trails” or trains. Tony Hallas captured two Leonids in a single frame with glowing trains during the 2001 shower. Credit: Tony Hallas

Watch out for flammable comet dust the next few nights. ‘Tis the season of the Leonids. This annual meteor shower, which originates from dust dribbled by comet 55P/Temple-Tuttle, peaks tomorrow and Tuesday mornings November 17-18.

About every 33 years the Leonids produce a spectacular display. This illustration from a newspaper at the time captures the intensity of the shower on November 13, 1833. The next Leonid storm is expected in 2034.

Every 33 years, when the comet swings into the inner solar system, Leonid numbers swell into the hundreds if not thousands per hour and create what’s better described as a meteor storm. The most recent storm unfolded in 2000-2001; now we’re down to the Leonids’ usual peak of 10-15 per hour.

Admittedly, that’s more like a light drizzle than a shower, but what the Leonids lack in numbers in off-years, they make up for in character. Because the Leonid stream travels around the Sun in a direction opposite to the planets, Earth hits Tempel-Tuttle’s debris head-on at very high speed. Leonids pepper the planet at speeds upwards of 158,000 miles per hour (70 km/sec), the fastest of any shower.

They often burn brightly as fireballs and leave glowing streaks of ionized air in their wakes called trains. Upper atmospheric winds can distort and stretch the trains over several minutes time, a sight well worth watching. In 2001, we saw a fair number of these long-lasting “smoke trails” after the appearance of fireballs.

 

This map shows the sky facing east around 3 a.m. Monday November 17th. The radiant is well-placed near Jupiter in Leo. The thick crescent Moon rises around 2 a.m. Monday and 3 a.m. Tuesday. Stellarium

Watching the Leonids is easy as long as you’re willing to wake up in the wee hours. Patience helps too. You may see nothing in the first 10-15 minutes and then all at once a swift blade of light slices the sky. The radiant or point in the sky from which the meteors originate rises around 11:30 p.m. local time in Leo near Jupiter. But the best time to view the shower is from about 3 a.m. till dawn when the radiant is high in the east-southeast.

Both Monday and Tuesday mornings are good for shower watching. Light from the crescent Moon will hardly be a bother. Dress warmly and get comfy under a blanket in a reclining lawn chair facing east or south. Relax back and watch the stars slowly parade above you. Every meteor you see will come both as a pleasant surprise and reminder that Earth is continually touched by comets.

Guess who’s up before midnight? By Jove, it’s Jupiter!

Brilliant Jupiter now rises in the northeastern sky before midnight. The waning gibbous Moon will join the planet Thursday November 13th. This map shows the sky facing east at midnight in mid-November. Stellarium

If the sky’s seemed devoid of evening planets of late, you’re right. Mars still hangs on in Sagittarius, but it’s so low and sets so early, few notice. Most telescopic observers have long since abandoned the planet. With an apparent diameter of three-one-thousandth’s that of the Moon, it’s just too tiny to eke out any details.

Venus is also “officially” an evening planet but still much too close the Sun to view. Enter Jupiter. This jolly bright planet joins the evening crew with a bright flourish, rising in Leo the Lion. In the days of Daylight Saving Time it rose around 1 a.m. but now catches our eyes a little before midnight low in the northeastern sky.

Jolly Jove on November 8, 2014. The two big stripes are the North (top) and South Equatorial Belts. The Great Red Spot is seen along with a cluster of smaller oval storms. Credit: Christopher Go

Earth’s revolution around the Sun causes the stars and planets in the eastern sky to rise 4 minutes earlier each evening, while those in the west set 4 minutes earlier. Over time, stars in the west get pushed out of the way as those in the east rise higher and take over the sky. It’s the astronomical equivalent of seeing each older generation swept away by the little babes whose job it is to replace us.

My point is that Jupiter, while low now, will rise an hour earlier by Thanksgiving  (16 nights x 4 mins. = 64 minutes) and nearly 3 hours earlier by Christmas. We’re soon to see a lot more of this planet. So goes the cycle of the sky.

Three of Jupiter’s four bright moons will be visible in small telescopes tonight. This view shows them around midnight (CST) tonight. North is up. Stellarium

Not only is Jupiter a pleasure to see with the naked eye – it’s so darn bright – but its dynamic weather and four bright moons offer telescope users something new to see every time we look through the eyepiece.

Because Jupiter’s 11 times larger than Earth, it presents a huge disk compared to most planets. Even with a 3-inch scope you can watch the moons shuttle back and forth and spy the largest clouds belts. The Great Red Spot, an enormous hurricane-like storm, has been shrinking over the last decade but can still be spotted in 6-inch and larger instruments.

The 2014-2015 apparition of Jupiter is special because Earth crosses through the planet’s orbital plane. Since the four brightest moons orbit almost exactly around Jupiter’s equator, we’ll get to see them eclipse and occult one another. Eclipses are especially interesting to watch – over a few minutes time you can actually watch a moon temporarily fade away. I’ll have more on these fascinating events soon.

Mercurial delights / Supernova in spiral galaxy M61 / Jupiter spots

Mercury shines brightly in the east-southeast more than an hour before sunrise this morning November 1. The planet remains well-placed for viewing for the coming 10 days. Credit: Bob King

Scattered thin clouds took nothing away from this morning’s otherwise clear sky. With the Moon waxing from quarter to gibbous phase, the slab of darkness between moonset and dawn gets sliced thinner every day. Starting November 4th the Moon will light the sky all night and not give back the darkness till next weekend. I took advantage of a moonless morning to set up the telescope to view two comets, a brand new supernova in the bright Virgo galaxy M61 and the planet Mercury at dawn.

Around 7 a.m. CDT (6 a.m. CDT) in bright twilight, Spica cleared the treetops about 5 degrees to the lower left of Mercury. Watch in the coming mornings as Spica slides up higher in the sky and Mercury slowly drops horizon-ward. Credit: Bob King

Normally I suggest looking for Mercury around 45 minutes before sunrise when it’s high enough for a good view, but if you have an wide open eastern horizon, go for it earlier. The planet is very bright right now at magnitude -0.6 — brighter than it’s nearest rival, Arcturus (0.0) located three outstretched fists to the upper left of Mercury. I was surprised at how bright and easy it was to see it more than an hour before sunrise.

In the next few mornings, Virgo’s brightest star Spica rises near the planet. Watch them do a do-si-do in the coming days as Spica passes Mercury.

Facing east about 50 minutes before sunrise tomorrow and Monday Nov. 2-3. Mercury will be near Spica and about three outstretched fists to the right and below Arcturus. Source: Stellarium

Gianluca Masi captured this view of the supernova 2014dt (tick marks) in the 9th magnitude barred spiral galaxy M61 in Virgo on Halloween. The galaxy is some 55 million light years from Earth. Credit: Gianluca Masi

Virgo brings more than a bright morning planet. Tucked with the broad “Y” or cup-shaped northern half of the constellation, the bright galaxy M61 glows with a brand new supernova visible in amateur telescopes.

Japanese amateur astronomer Koichi Itagaki discovered the new star on October 29 at magnitude +13.6. A little on the faint side, yes, but it has been slowly brightening. This isn’t the first time we’ve witnessed a supernova explosion in the galaxy. At least two others – 2006in and 2008ov – have been observed. Quite the hotbed!

View looking east just before the start of morning twilight. M61 is located in the big Virgo “Y” about three outstretched fists to the right and above brilliant Arcturus. Source: Stellarium

Enlarged view of Virgo to help you better track down M61. When you find it, the supernova will look like a star inside the galaxy east of the core. Click for a large version. Source: Stellarium

Right now, you’ll need an 8-inch or larger telescope and dark sky to see it. The best time is just before dawn when Virgo is highest in the eastern sky. Through the eyepiece of my 15-inch (37-cm) scope this morning the galaxy glowed big and round with a bright core. Supernova 2014dt was a dim “star” 40 arc seconds east and 7 seconds south of the nucleus. Use the maps above to help you find the galaxy.

This morning’s shadow transit of Jupiter’s largest moon Ganymede (left) and a future transit that will occur on November 8 between 3:35 – 7:12 a.m. CST. The Great Red Spot will also be nicely placed for viewing. Add 1 hour for EST, subtract 1 hour for MST and 2 hours for PST. Source: Meridian

I always save the bright planets for last not only because they provide a refreshingly bright treat after hunting comets and supernovae but also because I don’t want to destroy my night vision. But I got a great surprise when pointing the scope at Jupiter. Plain as could be, there was the shadow of the planet’s largest moon Ganymede silhouetted against the white clouds of the equatorial zone and next to it, Ganymede itself. For a minute it looked like two moons casting shadows on the planet. Compared to its shadow, Ganymede was smaller and gray-toned.

You can catch the next Ganymede shadow transit visible in the western hemisphere on the morning of November 8 from 3:35 to 7:12 a.m. CST. A 3-inch or larger telescope is all it takes to view it.

The sun rises just before 8 a.m. over the Wisconsin shoreline of Lake Superior this morning November 1. Credit: Bob King

What better way to top off a morning of sky watching than with a sunrise? Now maybe I’ll take a nap.

Jupiter-moon conjunction / Space station expecting guests / Hello Mars!

Tomorrow morning September 20th the crescent moon will be lined up in conjunction with the planet Jupiter ahead of the Sickle of Leo. This view shows the sky a little more than an hour before sunrise. Stellarium

Getting a little extra sleep these September mornings? That benefit comes from later sunrises as we approach the fall equinox. I don’t know about you, but I sleep better in a darkened bedroom.

The rate of change has really picked up in the past few weeks with the sun now rising around 7 o’clock, a far cry from late June’s 5:15.

Later sunrises also mean a chance to catch an early morning sky event. Many of us are active around 6 a.m. prepping for work or getting your children ready for school. If you can find a few minutes to spare, tomorrow morning offers up two fine sights.

Look east in the brightening dawn and you’ll see a slender crescent moon in conjunction with the brightest of the planets, Jupiter. The two will just 5º apart meaning you’ll be able to squeeze three fingers held at arm’s length between them. Then, between 5:30-6:15 a.m. now through at least next week, the International Space Station (ISS) will be making regular passes across the northern sky from many locations across the U.S., Canada and Europe.

To find out exactly when and where to look, key in your zip code at Spaceweather’s Satellite Flybys site or select your city at Heavens Above. The ISS looks like the brightest “star” in the sky and travels from west to east. A typical complete pass takes about 5 minutes.

An earlier SpaceX Dragon capsule docking with the space station in March 2013. Astronauts will use the grapple arm to grab the capsule Monday morning Sept. 22 at around 6:30 a.m. CDT. Berthing begins around 8:45. Click to enlarge. Credit: NASA

The three current astronauts aboard the space station await the arrival of the other half of their crew next week. NASA astronaut Barry Wilmore, Soyuz Commander Alexander Samokutyaev and Flight Engineer Elena Serova will launch aboard their Soyuz spacecraft from the Baikonur Cosmodrome in Kazakhstan on Sept. 25 to begin a six-hour, four-orbit trek to the orbiting complex.

Before that, SpaceX’s unmanned Dragon ship will launch tomorrow morning Sept. 20 at 1:14 a.m. Central time to deliver cargo and crew supplies to the ISS early Monday morning Sept. 22nd.

Among the items are the first 3D printer in space, the ISS-RapidScat instrument to monitor ocean winds for climate research and weather forecasting and a commercial experiment designed to make a better golf club. The printer will allow astronauts to make their own tools and replacement parts that would otherwise cost a lot of money to ship up from Earth.

Fruit flies such as these spent one month aboard the International Space Station during an earlier study. More are on the way. Credit: NASA / Dominic Hart

20 female mice and 30 fruit flies will also go along for the ride. The mice will be housed in the new Rodent Research habitat, where they’ll be studied for the effects of spaceflight on the human body. In space, rodents don’t spend their time floating around. They’re very physically active but tend to hold onto the walls.

Fruit flies will be monitored for the effects of oxidative stress changes which happen in organisms ranging from fruit flies to humans. Oxidative stress involves a build up of harmful molecules inside cells that can cause cell damage, and it’s associated with infections and disease.

Artist view of India’s Mars orbiter at Mars. Arrival and orbit insertion is expected for Sept. 24. Credit: ISRO

There’s much more in the works for space mission news as Mars welcomes two new emissaries from Earth. NASA will insert the MAVEN spacecraft into orbit around Mars Sunday night, and India’s Mars Orbiter Mission (MOM) will arrive at the planet only three days later on Sept. 24.

The MAVEN mission will study Mars’ climate present and past as scientists try to figure out how the planet evolved from a warmer, wetter past to the current dry, cold desert. MOM is India’s first-ever mission to another planet. While primarily a demonstration and testing of that country’s technology, MOM will also photograph the Red Planet and study its mineral makeup from orbit.

Hole-y auroras possible tonight Aug. 30-31 / Jupiter returns

The dark opening at the center of the sun’s disk, seen here in ultraviolet light, is a coronal hole photographed on August 28 by the Solar Dynamics Observatory. Holes are ports through which high speed particles from the sun can pour freely into space unconstrained by solar magnetic fields. Credit: NASA

Sometimes it doesn’t take a big solar storm to incite an aurora. Often enough, a hole will do. Midweek, a blizzard of electrons and protons called a coronal mass ejection arrived in Earth’s vicinity, snuck past our magnetic defenses and painted northern skies for several nights in a row with glowing curtains and rays.

Yesterday night, a coronal hole did the same. Coronal holes are openings in the sun’s otherwise ‘locked down’ magnetic canopy. In the photo above, swirls of magnetism form closed loops over most of the sun’s lower atmosphere, keeping the bubbling sea of solar plasma (charged particles) at bay.

Enhancements in the solar wind either from solar storms (CMEs) and coronal holes send a thin soup of electrons and protons into space. If a batch happens to have a southward-pointing magnetic field, it can open a crack in Earth’s northward-pointing field and stimulate oxgen atoms and nitrogen molecules to glow in the upper atmosphere. The aurora is concentrated in two ovals, one hovering over each magnetic pole. Credit: Todd Salat

The sun’s so hot that it energizes and accelerates bits and pieces of itself – electrons and protons – to speeds high enough to escape its gravitational pull. Astronomers call the gust of departing particles the solar wind. Typical speeds hover around 250 miles per second (400 km/sec), but winds leave coronal holes unchecked and can blast into space at up to 500 miles per second (800 km/sec).

When the tempest arrives at Earth and harbors south-pointing magnetism, it links into Earth’s north-pointing magnetic field, sending electrons and protons at high speed down the planet’s magnetic field lines into the upper atmosphere to spark auroras.

Coronal holes are holes where the sun’s magnetic field where the solar wind can escape at high speed. Credit: NASA

NOAA space weather forecasters expect the effects of coronal holes to continue tonight and linger through Monday. Peak possibility for northern lights tonight happens between 10 p.m. and 1 a.m. CDT. Sometimes a particular hole can persist for several solar rotations causing repeat auroras every 27 days.

Stay tuned to Ovation aurora to see if any auroras are dropping south toward your region tonight.  I’ll be in touch.

Jupiter (top) and Venus in bright twilight on August 27, 2014. Credit: Bob King

The other morning while watching aurora I was happy to see that Jupiter had jumped back into the sky. It cleared the trees during twilight and was followed a half hour later by Venus. Low elevation and wiggly air currents meant I couldn’t magnify it much, but at 64x but north and south equatorial belts were unmistakeable.

I always look forward to that first view of Jupiter after conjunction with the sun. We last saw the planet in June, quite a while back. Jupiter’s weather and cloud patterns constantly change. One never knows what to expect when it’s out of sight for a couple months – sometimes an entire equatorial belt can disappear! I’m hear to report that both are still intact.

Know your planet and eat it too

A Jupiter cake made by Rhiannon, who writes the Cakecrumbs blog, shows the giant planet’s layered atmosphere and interior in a fun and realistic way. Click for recipe. Credit: Rhiannon

I had no idea Jupiter had a mud cake core surrounded by almond butter cake and enveloped with a blue-tinted vanilla Madeira sponge. Topped off with vanilla buttercream and marshmallow icing, it’s the first planet that’s ever made my mouth water.

The Great Red Spot inspired Rhiannon to pick Jupiter for her cake. The iconic feature is instantly recognizable. She used ivory, brown and maroon edible ink to dry brush the Spot and other atmospheric features like belts and vortices on the outer layer of marshmallow fondant (icing). Credit: Rhiannon /cakecrumbs.me

Rhiannon, who writes the Cakecrumbs blog, had two passions as a child, animals and the solar system. A self-taught cook and cake decorator, she recently created what she calls her “Jupiter Structural Layer Cake” based on current knowledge of the planet’s atmosphere and interior.

Why Jupiter? It wouldn’t surprise you to know that the Great Red Spot – that huge storm more than twice the size of Earth that’s been whirling around up there the past few hundred years – has always been one of her favorite outer space personalities.


Jupiter concentric layer cake tutorial

Painting on the Red Spot and many other atmospheric details, all based on photos of the planet over many years, took 8 hours, just 2 hours shy of one complete rotation of the real Jupiter. That’s dedication.

You’ll have to watch the video to appreciate the details (three baking steps were required), but to create the sphere, she joined two cake hemispheres with buttercream.

The non-cake Jupiter spans nearly 87,000 miles across and is striped with jet-stream like belts of ammonia ice clouds. Earth is shown for comparison. Credit: NASA

Rhiannon cautions that her cake is “totally not to scale”, but she’s got the details down. Jupiter’s marshmallow cream atmosphere is mostly hydrogen and helium with clouds made of ammonia ice and even water ice further down. All those lovely yellows, reds and oranges so lovingly applied with tiny brushstrokes of food coloring are likely trace amounts of compounds of sulfur, carbon and phosphorus in real life.

Below the clouds, Jupiter just gets weird. Its atmosphere reaches down for thousands of miles. In December 1995, NASA’s Galileo spacecraft released an Entry Probe toward the planet. As the craft descended into the maelstrom of Jovian clouds, it transmitted data back to the orbiter for just 58 minutes. At a depth of 373 miles (600 km), transmissions stopped as the machine was presumably crushed by the extreme atmospheric pressure. Pressures at the base of Jupiter’s atmosphere are 4 million times what we experience on Earth.

Cutaway showing both the cloudtops and the interior of Jupiter. About 75% of the planet’s weight is taken up by fluid metallic hydrogen. Jupiter’s composition is very similar to the sun’s, and like the sun, it’s very hot in the center, but not hot enough to ignite hydrogen and burn as a star.

It only gets more intense as you approach the core. At a certain depth, airy hydrogen is compressed by the vast amount of material above it into liquid molecular hydrogen (the blue cake layer). Below that we arrive at a truly exotic form of matter, liquid metallic hydrogen (white cake).

Under the extreme pressures and heat near the core, ordinary hydrogen gets squeezed so tightly, its electrons depart and move about just like they do in metals. And just as metals conduct electricity, so too this bizarre hydrogen cousin. If you could somehow touch it – impossible because it can’t be created on Earth – it would resemble liquid mercury.

Don’t care for Jupiter? How about a slice of Earth? This is one of Rhiannon’s earlier cakes. The slice shows the crust, mantle (red), outer core (yellow) and inner core. Credit: Rhiannon / cakecrumbs.me

Jupiter’s intense magnetic field is thought to arise from the rapid spinning of this electric liquid. Deeper down, we meet a putative core of rock (mud cake), something like the Earth in composition, but 10-15 times more massive.

Have you had enough cake yet?

 

Miss the conjunction? Here’s your consolation prize

Clear skies prevailed over Königswinter, Germany for a great view of Venus and Jupiter just 0.2° apart at dawn this morning August 18. Credit: Daniel Fischer

Those killers of all things astronomical – clouds – were back again this morning, so no Venus-Jupiter conjunction here. Looks like I’ll pin my hopes on the one scheduled for next June 30 in Leo at dusk. I’m grateful for the flatness of the solar system, which guarantees that every few years we get repeat planet pairings.

Look east this coming Saturday morning for a sweet pairing of the bright planets and wiry crescent moon. This view shows the sky about 45 minutes before sunrise. Stellarium

I hope some of you got to see the conjunction from your home or on the way to work this morning. While Venus and Jupiter will now part ways, they’ll be one more blast of celestial awesomeness involving the duo and the crescent moon this weekend. Consider it a consolation prize. Who knows, this event might be even prettier than what passed this morning.

On Saturday morning, August 23rd about 30-45 minutes before sunrise, the thin, waning lunar crescent joins Jupiter and Venus in a stunning triangle of loveliness in the eastern sky.The threesome will all fit inside an 8° circle.

Now that I know this is coming I don’t feel so bad about missing the conjunction.

Two weeks of hell on Io

Last August, Jupiter’s moon Io experienced three massive volcanic eruptions within a two-week period. This Aug. 29, 2013 outburst on Io was among the largest ever observed. This image was taken in near-infrared light which shows the hot lava flows as bright blobs. Credit: Katherine de Kleer/UC Berkeley/Gemini Observatory

Little Io is the most volcanically active body in the solar system. Last August it made sure we were all aware of that fact with three great outbursts spread over just two weeks.

Ever since the twin probes Voyagers I and II passed the Jupiter system in 1979, we’ve known that the planet’s innermost large moon is literally bubbling with activity in the form of volcanic eruptions, fire fountains and sheets of hot lava spilling across its surface.


Eruption of Io’s Tvashtar volcano photographed by the New Horizons spacecraft in 2007. The plume reached about 102 miles (165 km) high.

With over 400 active volcanoes activity never ceases, but massive outbursts typically happen every one or two years … or so it was thought. Last August, to astronomers’ surprise, three massive volcanic eruptions occurred on Jupiter’s moon Io within a two-week period.

Io up close, photographed by the Galileo probe, shows numerous volcanoes and lava flows. Dark spots mark sites of current volcanic activity. Lava on the little moon can be as hot as 2,400°F (1,300°C), hotter than Earth’s peak of 2,190°F. Credit: NASA

“We typically expect one huge outburst every one or two years, and they’re usually not this bright,” said Imke de Pater, professor and chair of astronomy at the University of California, Berkeley, and lead author of one of two papers describing the eruptions. “Here we had three extremely bright outbursts, which suggest that if we looked more frequently we might see many more of them on Io.”

These images show Jupiter’s moon Io obtained at different infrared wavelengths (in microns, μm, or millionths of a meter) with the Keck Observatory’s 10-meter Keck II telescope on Aug. 15, 2013 (a-c), and the Gemini North telescope on Aug. 29, 2013 (d). Credit: Imke de Pater and Katherine de Kleer/UC Berkeley/Gemini/Keck

Only on Io do volcanoes spew lavas as intensely hot- hotter actually – as those found on Earth. Because of the moon’s low gravity, rock shot out of Io’s volcanoes can reach as high as several hundred kilometers, much higher than Earth’s best efforts (60-70 km).

“The amount of energy being emitted by these eruptions implies lava fountains gushing out of fissures at a very large volume per second, forming lava flows that quickly spread over the surface of Io,”  said Ashley Davies, volcanologist and colleague of de Pater.

Katherine de Kleer, a UC Berkeley graduate student, determined the temperature of the lavas released in the massive eruptions as likely hotter than lavas on present-day Earth but similar to what’s believed to have covered our planet shortly after its formation 4.5 billion years ago. Study of Io’s lava flows may help us understand how the surfaces of Earth, Venus and the moon were formed.

In Tupan Patera on Io, an island of solid sulfates floats atop a lake of hot, black lava. The feature is 50 miles (80 km) across and surrounded by a 2,950 foot high cliff. (900 meters). Credit: NASA

With it crazy mix of yellows, oranges and reds, Io’s often likened to a pizza, which seems very fitting especially if you’ve been burned by molten cheese dripping from the edge of your slice. The ‘cheese’ or lava on Io is molten sulfur and its compounds which give the its spectacular color palette.

Io’s volcanic activity is the result of a combination of gravitational forces:  Jupiter’s powerful gravity pulls it toward the planet while the moons Europa, Ganymede and Callisto pull it in the opposite direction. The opposing forces squeeze and stretch the hapless moon, causing its crust to rise and fall by 300 feet (100 meters). The tremendous friction generated heats and melts interior rocks to form lava that find its way to the surface through fissures in the crust. You’ll have to look hard to find any craters on Io as the crust has been resurfaced time and again by flows of molten rock.

Only about as big as Earth’s moon, Io is a clearly a horse of a different color all because it finds itself under very different circumstances.

Shhh! Don’t wake the sun

Contrast these views of the nearly spotless sun on July 16-17, 2014 with a picture taken about two weeks earlier (below). Credit: Giorgio Rizzarelli

Who doesn’t enjoy a nap on a lazy summer afternoon? That’s what the sun’s been up to past few days. Instead of a steady parade of sunspots, it put its pencils away and went to sleep. For a time on July 17 not a singe magnetic blemish marred the entire Earth-facing hemisphere. The last time that happened was nearly 3 years ago on Aug. 14, 2011.

Ten groups including three visible with the naked eye dot the sun on July 8, 2014. Credit: NASA

The solar blank stare lasted but a day; by the 18th two small groups emerged. Today three little spot clusters have emerged but again, they’re on the small side.

I think the reason the sun looks so stark is that only two weeks ago nearly a dozen sunspot regions freckled the disk including three visible with the naked eye with a safe solar filter.

These ups and downs aren’t unusual unless this downturn continues for weeks. Expect more bubbles of magnetic energy to rise from beneath the glaring surface of the sun called the photosphere and spawn fresh groups soon. Because we now have eyes on the farside of the sun courtesy of the dual STEREO solar probes, we know the complete story. There are at least seven spotted regions in hiding there today.

Sunspot numbers are plotted for the last three solar cycles through the present. The double peak of the current cycle is shown. Credit: NASA

Sunspots and flares peak approximately every 11 years. We’re still riding the roller coaster near the top of the arc after the most recent solar maximum in late 2013. Some maxima are strong, others weak. The current max – Cycle 24 – is the weakest since Cycle 14 in February of 1906 and one of the wimpiest on record. Occasionally a cycle will have two peaks like the current one. The first peak occurred in Feb. 2012 and the second just this past June. What makes Cycle 24 even more unusual is that the second peak is higher than the first – the first time this has ever been recorded. Like people, every maximum has a personality of its own.

Doug Bieseker of the NOAA Space Weather Prediction Center has analyzed historical records of solar activity and he finds that most large events such as strong flares and significant geomagnetic storms typically occur in the declining phase of solar cycles—even weak ones, so don’t give up hope for some great auroral displays ahead.

A coronal mass ejection blew off on the farside of the sun early this morning July 20. It appears to envelop Jupiter, but the planet is 490 million miles in the background. SOHO uses an occulting disk to block the brilliant sun. Credit: NASA/ESA

The sun’s got a buddy this week – Jupiter! We can’t see the planet from the ground because it’s swamped by solar glare, but the Solar and Heliospheric Observatory (SOHO) has a great view from space. Watch the sun approach from the right and pass the planet over the next few days. After the 24th, Jupiter will move into the morning sky.