Monthly Archives: December 2010

Best astro stories and photos of 2010

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I don’t know how I ended up with a Top 15 story list for 2010, but there you have it. I could have easily added more, but 15 is plenty! I don’t like ranking stories, because it’s hard to compare space probes to personal experiences like eclipses, so these are no particular order. Tomorrow we’ll touch on a few events to look forward to in 2011. I wish you all a Happy New Year and clear nights whenever you need them most.

Water on the moon!

A number of craters near the moon's south pole contain considerable amounts of water ice. Credit: NASA

Water was detected inside a crater near the moon’s south pole during last year’s LCROSS impact, but the true extent of lunar ice wasn’t revealed until this year, when the Lunar Reconnaissance Orbiter and a NASA radar instrument on board India’s Chandrayaan-1 lunar orbiter uncovered the “rest of the story.”An estimated 600 million metric tons of water ice could be hiding under and in the dust and soil inside craters clustered around the moon’s north and south poles. That’s enough to potentially sustain a manned moon base. Besides its obvious use for drinking, water can be separated into hydrogen and oxygen and converted into rocket fuel.

Potentially habitable exoplanets

Artist conception of the potentially habitable planet Gliese 581g (foreground at right) orbiting its host star, a red dwarf. Credit: Lynette Cook/NASA

To date, 516 planets beyond our solar system have been discovered. These exoplanets are primarily hot, Jupiter-sized gasbags orbiting very near their host suns. An exciting exception to this trend was the September discovery of Gliese 581g, located in the “habitable zone” where liquid water could exist on its surface. Also announced this year was the discovery of another exoplanet, GJ 1214b, which might be surrounded by an atmosphere of water steam. The planet is a so-called Super Earth, a globe more massive and larger than our own, but considerably smaller than the run-of-the-mill giant gas planets.

Hayabusa probe returns first-ever sample from an asteroid

Japanese scientists retrieve the precious capsule containing asteroid dust ejected by Hayabusa during its return to Earth. Credit: JAXA

Despite all kinds of trouble with equipment and what appeared at first like a failed attempt to grab a sample of the asteroid Itokawa, the Japanese Hayabusa probe not only returned to Earth this summer, but when scientists examined its return capsule, they discovered thousands of minute grains of asteroid dust. The probe landed on the asteroid’s surface and was supposed to fire projectiles, which would release dust from the surface into a capsule. But the projectiles failed to fire. Luckily, the force of landing sent a tiny quantity of dust into the capsule. Scientists are currently studying the grains, the first ever from an asteroid sampled directly from an asteroid.

Enceladus jets

Plumes of water vapor and other material issues from cracks in Enceladus' surface nicknamed "tiger stripes". Credit:NASA

Although water vapor jets were discovered shooting from fissures in the surface of Saturn’s icy moon Enceladus several years back, the pictures returned this year from the Cassini mission were simply exceptional. They look like a field of Old Faithful geysers. Scientists still debate their cause, but they probably stem from internal heating of the moon either through radioactivity or gravitational interaction with Saturn and its other moons.

Solar Dynamics Observatory (SDO)

A huge loop of flaming hydrogen gas called a prominence photographed by the SDO. Credit: NASA

Launched in February, the new solar observatory has been sending back the most beautiful and detailed images of sun in every wavelength (color) of light simultaneously and over very short time intervals that you, I and solar scientists have ever seen. We knew the sun was dynamic, but because SDO can image it over very short time intervals, it now looks positively alive with activity. Scientists have assembled the still images into jaw-dropping videos available on the SDO site as well as Youtube.

Bacteria living on arsenic found on Earth

The bacteria GFAJ-1, which can live off toxic arsenic. Credit: Jodi Switzer Blum

Although toxic to most living things, NASA researchers discovered a new strain of bacteria not only living off arsenic, but incorporating it into their DNA. The microbes were found in highly alkaline Mono Lake in California and are unique, because they don’t share the same fundamental building blocks of life used by the rest of our planet’s known life forms. Their existence reminds us that life on other planets may take other forms and use available chemicals and resources in exotic, unexpected ways.

Jupiter’s stripe disappears, then reappears

Jupiter last May when the SEB had disappeared.

This spring, Jupiter’s otherwise prominent South Equatorial Belt (SEB) faded from view, leaving the planet with only one obvious dark belt. Scientists think it was covered over by higher, whiter clouds. Then this fall, the belt began to return, beginning with the appearance of a dark spot called the South Equatorial Revival, which has since expanded completely around the planet. For anyone with even a small telescope, Jupiter has been the planet to watch in 2010. Changes in its cloud belts, and with four moons constantly on the move, Jupiter’s worth pointing the scope at every clear any night of the year.

Jupiter struck again by asteroid

The white impact spot in Jupiter's cloud tops on June3.

Jupiter made the news again on June 3, when it was hit by a small asteroid or comet. The flash of light from the impact was recorded by Anthony Wesley of Australia and Christopher Go of the Philippines.  Yet another impact flash was recorded just two months later by Japanese amateur Masayuki Tachikawa on August 21! Once thought impossibly rare to see, impacts have now been observed on four occasions on the giant planet. Each time we see such an event, we’re reminded of Earth’s vulnerability in a solar system that’s still has the feel of the Wild West even after 4.5 billion years of settlement.

Saturn’s monster storm dazzles at year’s end

Saturn's big storm seen in blue light by the Cassini probe. Credit: NASA

Planetary weather made the news once again with the appearance of an enormous storm that shot up from deep beneath the Saturn’s clouds earlier this month. Since then, it’s expanded to over 36,000 miles across. Recently, the Cassini probe picked up radio static from the storm, indicating that gigantic bolts of lightning are flashing within that big white cloud. Saturn’s lightning is thousands of times stronger than Earth’s. Who knows the holy terror of a storm there? Over the coming weeks, the storm will likely spread all around the planet and remain visible in amateur telescopes for some time to come.

Flyby of Comet Hartley 2

A close up of Hartley 2's jets shooting out clumps of fluffy snow. Credit: NASA

NASA’s EPOXI mission flew only 435 miles from the bowling-pin-shaped Comet Hartley 2 and photographed jets blasting fluffy snow into space. The source of the jets appears to be dry ice (frozen carbon dioxide) beneath the comet’s surface. Heat from the sun causes the ice to vaporize and carry along bits of water ice through cracks in the comet’s surface. At the same time as the spacecraft photographed the comet, it was a easily visible back on Earth with only a  pair of binoculars as sped near the W of Cassiopeia.

Hubble Space Telescope finds oldest, farthest galaxy

UDFy-38135539, the farthest galaxy seen so far. Credit: NASA/ESO

This fall, using the Hubble Space Telescope and the European VLT scope, discovered a galaxy that was around when the universe was only 600 million years old. Since the universe formed in the Big Bang 13.7 billion years ago, that’s one old galaxy. Seeing it takes us back 13.1 billion years to a time when stars and galaxies were just beginning to coalesce from the initial hydrogen and helium created during the Big Bang. Those stars cooked up new elements which were incorporated into later generations of stars and planets. Hubble is always breaking records – it’s a safe bet we’ll see even further back in time in 2011.

New cupola on the space station provides a picture window on the Earth

The "boot"of Italy at night from inside the cupola. Credit: NASA

The cupola, installed earlier this year on the International Space Station, is the largest window ever in space. It allows astronauts excellent visibility around the station for monitoring outside activities as well as providing an ideal place to view and photograph the Earth from orbit. The photos taken this summer of Italy, Egypt and other locales at night were amazing. Although most of us aren’t going to fly into space, seeing these photos is the next best thing.

Rise of solar activity and return of the northern lights

The northern lights as seen from Duluth on Oct. 11-12 this year. Credit: Bob King

Arctic sky watchers see the aurora even during lean years of solar activity, but this is the first time in several years that observers in the northern U.S. have spotted the lights. The sun experiences highs and lows in sunspot number and magnetic activity that are directly related to displays of the northern lights. We appear to have emerged from the bottom of the current cycle and are now headed back up toward solar maximum. The numbers tell all. In 2009 the sun was “spotless” 260 days; this year only 51.

Flyby of the asteroid 21 Lutetia

The asteroid 21 Lutetia by Rosetta. Credit: ESA

The European Rosetta spacecraft flew by the 81-mile-long asteroid 21 Lutetia this past July and turned what once appeared as a star-like object through a telescope into a real place with boulders, craters and contours. Scientists are still working to determine Lutetia’s composition. Meanwhile,  Rosetta continues onward to its 2014 rendezvous with Comet Churyumov-Gerasimenko. Shortly after arrival, it will deploy a small lander on the comet’s surface. Imagine – we’ll soon see what it looks like to stand right on a comet. Ain’t technology grand?

A colorful lunar eclipse

December's eclipse of the moon. Credit: Jim Schaff

Although cloudy at my place, this was the first total eclipse in a couple years and widely visible across much of the southern and western U.S. A lunar eclipse is always a highlight because it can be enjoyed without optical aid by millions of people across half the world. The next total lunar will be visible across the western U.S., Alaska and Asia December 10, 2011.

Distance brings the universe down to size

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Venus and the crescent moon will make you smile tomorrow morning as you look to the southeast during twilight. Those with a clear view further down near the horizon will also get a shot at seeing fleet-footed Mercury. Created with Stellarium

I hate to bring this up, but another very nice naked eye celestial event happens tomorrow morning, when it’s guaranteed to be raining, snowing, sleeting or all of the above. Of course that only applies to the upper Great Plains and the Midwest. I feel more optimistic for the rest of you.

Venus highly-reflective clouds hide a seriously volcanic landscape. This radar image taken by the Magellan spacecraft shows a lava flow that breached a rock wall and solidified into a huge fan. The flow is 1640 feet above the plain and scene covers 79 square miles. Credit: NASA/JPL

Venus and the lunar crescent will be pinned together in the sky at dawn, a sight worthy of your attention. If you’ve got a great horizon view, look very low to spot Antares, the brightest star in Scorpius the Scorpion, and further east, the planet Mercury. Binoculars will make finding Antares and Mercury easier. You’ll also notice that the planet outshines Antares despite being millions of times smaller. When it comes to the cosmos, distance nearly always trumps intrinsic brightness and size. The closer you are, the brighter you are. Antares is large enough that if put in place of our sun, it’s girth would reach beyond Mars. It’s also 10,000 times brighter, but its 550 light year distance cuts it down to size. What is Mercury but a crumb in Antares’ eye?

Drop by again tomorrow, when we’ll look back at some of the best celestial events, stories and photos of 2010.

Although Mercury displays volcanic features like Venus, cratered landscapes resembling the moon are far more common. This photo, taken during the second flyby of the Messenger space probe, is of the 53-mile-wide crater Debussy. It's surrounded by rays hundreds of miles long created during the impact blast. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Winter Hexagon sparkles in the east

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Have you noticed Vega in the evening like my mom? It's easily seen in the northwest in late twilight. Maps created with Stellarium

I called my mom the other night to tell her the International Space Station would be flying over her house in southwestern Wisconsin in an hour. She got out on time and enjoyed the sight, but had a question about that big bright star in the northwestern sky. That’s Vega, I told her, one of the stars in the Summer Triangle. You may have noticed Vega these late December evenings, especially if you’re on your way home from work around 5:30-6 p.m. The star’s low altitude makes it an easy catch through the car windshield if you happen to be driving north or northwest and encounter a swatch of unobstructed sky.

Vega is the brightest star in the Triangle, and the one most of us notice before the others two: Deneb of Northern Cross fame and fast-disappearing Altair in Aquila the Eagle. These summer stars will linger a few more weeks before they’re displaced by a wave of late fall and winter stars moving up from the eastern sky.

The Winter Hexagon reaches from Sirius, low in the southeast, to Capella, near the top of the sky. It's formed by the brightest stars of winter's most prominent constellations.

Vega sets around 10 p.m., not long after the entire Winter Hexagon clears the horizon on the opposite side of the sky. Seven of the nine brightest stars of winter compose this large and delightful asterism. Go out around 9 o’clock and start with Orion’s Belt. Below and right of the belt is Rigel. From there, drop down to Sirius, the brightest star in the sky, and then work your way back up through Procyon (PRO-see-on), the Gemini Twins and to Capella. Then come back down through Aldebaran in Taurus and return to Rigel. Or go another way altogether.

With all side of the Hexagon complete, let’s not forget Betelgeuse, the lone bull in a six-sided corral.

Bright comet prospect for 2011

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A pretty arrangement of two stars, two planets and the moon this morning at dawn. Details: 16mm lens at f/2.8, 15-second exposure, ISO 800 Photo: Bob King

Looks like 2011 will bring us a fine morning comet. Comet Elenin (C/2010 X1) was discovered on December 10 by Leonid Elenin of Lyubertsy, Russia using a “remote” telescope in New Mexico via the Internet. Although still very dim and distant – 375 million miles from the sun – its preliminary orbit indicates a fairly close pass by the sun September 5 next year. On its outbound journey, Comet Elenin will swing near the Earth and brighten up to binocular and likely naked eye visibility. The geometry of sun-comet-Earth after perihelion (closest approach to the sun) looks favorable for a standout tail. Watch for Comet Elenin to track along the zodiac in Leo the Lion in October’s morning sky.

We’ll keep you posted on predictions when it might first become visible as the comet’s orbit is refined. To see Russian news video of the discoverer and his comet, please click HERE.

Two views of Saturn's storm taken by the Cassini probe. At left we see it through a filter that enhances the light from methane gas in the planet's upper atmosphere. The ring plane is visible as a spider-web-thin line above the much broader shadows cast by the rings. Credit: NASA/JPL/Space Science Institute

Well, I finally got my first chance to look at Saturn since the giant storm appeared in the planet’s northern hemisphere a few weeks back. The sky was perfect but hid an unfortunate secret invisible to the eye – air turbulence. As soon as Saturn was centered in the field of view, I could see the trouble right away. The image bounced, boiled and blurred at a furious pace. Despite my best efforts over the next 45 minutes, there weren’t enough moments of calm air to be sure of seeing anything. At times, the rings looked like fat lobes on either side of the planet, much the way Galileo must have seen them in his small telescope. Now I know why he didn’t even know what he was looking at.

That’s OK. I’ll try again. Thankfully we have two superb new photos taken on Christmas Eve by the Cassini probe at Saturn. The storm is nothing short of spectacular when you have a ring side seat. While you enjoy the pictures, consider that the main storm spot is 3,600 miles wide or nearly as big as Mars. The entire storm cloud measures 36,000 miles across.

We’ve got all the angles covered

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A triangle within a triangle defined by five bright luminaries will be a fun sight to see for early morning sky watchers. Although the map shows the sky an hour before sunrise, you can see the configuration anytime between 3:30 and dawn. Created with Stellarium

I’m on the road today with only a few free minutes. Enough time to tell you about a cool configuration of celestial bodies tomorrow morning involving Saturn, the last quarter moon, Spica, Arcturus and Venus.  Together they’ll form a small triangle within a much larger one. We can always find interesting alignments connecting this star and that, but the moon and planets, which are constantly on the move, create fascinating one-time arrangements worth your attention.

Lord of the Rings vs. the Dragon

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Two views of Saturn's storm taken 10 days apart show its dramatic expansion. Credit (left): Anthony Wesley, (right): Freddy Willems

Though I’ve yet to see the big storm on Saturn, that doesn’t mean I haven’t been lifting the window shade every morning at dawn in hopes of one, just one, break in the clouds. Other more fortunate amateur astronomers continue to observe and photograph the rapidly expanding white storm cloud as it churns its way across the planet’s North Tropical Zone. I encourage amateur astronomers equipped with 6-inch and larger telescopes to brave the cold dawn and have a look for themselves. The following is a list of Central Standard times when the seat of the storm will be centered (or nearly so) on the planet’s disk. Saturn is up high enough by 4 a.m. for a good view and due south by 7 during morning twilight. The spot should be in good, but not ideal visibility, up to an hour before and after the times shown. (*Note: times have been updated as of 12/28)

  • Tues. morning December 28 at 7:45 a.m.
  • Weds. December 29 at 5 a.m.
  • Sat. Jan. 1 at 7:30 a.m.
  • Sun. Jan. 2 at 5 a.m
  • Weds. Jan. 5 at 7:30 a.m.

In this 2004 image, the loopy feature above and right of center is nicknamed the Dragon Storm. It lies in a region of the southern hemisphere referred to as "storm alley" by imaging scientists because of the high level of storm activity observed there by the Cassini probe. Credit: NASA/JPL/Space Science Institute

This new storm is possibly a reappearance of the infamous “Dragon Storm” which breathed fire into Saturn’s southern hemisphere in mid-September 2004. So named because of of twisted shape, the Dragon Storm crackled with lightning and radio static. Scientists determined that it was a monster thunderstorm created when powerful currents of warmer air rose from the deeps into Saturn’s colder upper atmosphere. As the air cooled, it released heat, adding more energy to the mix, which drove even stronger winds. Electrical charges were built up by the collision of cloud droplets and hail in powerful rising and falling winds the way they do on Earth, resulting in lightning discharges. Eventually the material within the rising bubble cooled and condensed into ice crystals, creating a blizzard of ammonia ice. Apparently the Dragon is a long-lived disturbance that migrates around the planet out of view until it resurfaces as a powerful tempest.  Sounds more like mole behavior than that of a serpent.

Saturn photographed by Cassini on Dec. 22 showing a portion of the big storm in progress. Credit: NASA/ JPL/ Space Science Institute

I dug around and could only find one photo taken of the current storm by the Cassini probe orbiting Saturn. Cassini’s observations are planned months in advance, and it’s difficult to make changes in the observation plan. Ditto for the Hubble Space Telescope. That’s why the majority of photos available right now were taken by amateur astronomers, who can alter their plans at a moment’s notice to take advantage of any opportunity. The images in the panel at top were made by amateurs in Hawaii (Willems) and Australia. Add in the Internet, and you’ve got eyes on the sky and pictures to share 24 hours a night. Cassini should be in a better position soon to take more closeups. In the meantime, I’m hoping the clouds here in Duluth will loosen their Grinch-like grip on the stars.

Halley’s Comet stands in for the Star of Bethlehem

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Merry Christmas and a happy holiday to everyone stopping by today! I’m grateful for your interest in the sky and happy to share the wonders of the natural world with like minds. Thank you also for your photos, observations and comments throughout the past year – the more we share, the more we learn together.

In this fresco by Giotto di Bondone, the Star of Bethlehem is shown as a comet - likely the most famous of all, Halley' Comet.

With Christmas being celebrated by so many today, I thought it would be appropriate to find a little astronomy in the season. This painting by Florentine artist Giotto di Bondone, who lived from 1267 to 1337, is titled Adoration of the Magi and was painted around 1305. It’s one of his many frescoes depicting the lives and Mary and Christ in the building today known as the Arena Chapel in Padua, Italy. What’s special about this particular one, is the “star” painted above the manger. According to the Bible, the Wise Men followed a star,  which stopped above the place where Jesus was born. But if you look closely, you’ll see Giotto painted a comet, not a traditional star. And it’s a good resemblance, too. A large, ball-like head or coma with a pointed, upward-slanting tail. Looking back through my own comet sketches, more than a few resemble Giotto’s, though mine lack his artistic sensibility and color.

I suppose you could argue that it also resembles a meteor, but it’s unlikely that’s what Giotto had in mind. A meteor, however bright, flashes by in a second or two and is gone. Assuming the artist wanted to hold true to the Biblical narrative, the “star” would need to hover and stay lit for some time. That’s just what comets do – they look meteoric but move slowly across the sky orbit like the planets do.

Halley's Comet photographed in 1910. The comet passes near the Earth every 76 years as it orbits the sun.

Scholars think it likely Giotto was inspired by none other than Halley’s Comet. It appeared low in the northwestern sky over Italy only a few years earlier in the fall of 1301. Compare Giotto’s painting with the photograph taken under similar circumstances during its swing by Earth in 1901. There are good similarities between the two appearances. Who wouldn’t have been inspired by the appearance of a comet in the evening sky? With light pollution far off in the future, Italian skies would have been as dark as the best rural skies are today. You couldn’t miss it at dusk. Halley’s Comet would have been the talk of the town that fall.

While our ancestors generally gave comets a bad rap, blaming them for every pestilence and ill fortune, they were also seen as signs of change, sometimes for the good as when a new king ascended the throne. It’s not far fetched that Giotto might choose a comet, especially one with which he was familiar,  as a symbol of change for the Star of Bethlehem in his painting. Interestingly, no one at the time knew they were seeing Halley’s Comet. People had no idea comets orbited the sun and reappeared after a span of years. They were unpredictable, fiery, one-off phenomena thought to be part of the atmosphere, not frozen dust balls obediently following the laws of celestial mechanics. It was Englishman Edmund Halley, using Newton’s newly-formulated laws of gravity, who found that the comets of 1531, 1607 and 1682 were different appearances of the same comet. In his honor, it was named Halley’s Comet.

Artist impression of the Giotto mission flyby of Halley's Comet during its last pass by Earth in 1986. Credit: Andrzej Mirecki

In March of 1986, a European space probe flew 400 miles from the nucleus of Halley’s Comet, taking pictures and examining its surface and dusty-gassy coma in detail. The probe was named Giotto in honor of the artist who gave us what is likely the first realistic portrait of a comet in Western art.

I leave you with two famous comet coincidences. When Giotto painted Halley’s Comet, he didn’t know that Halley had also appeared in the year 12 B.C., within a half dozen years of the best estimate of Jesus’ birth. The other comes to us from American writer and humorist Mark Twain, who was born when Halley passed by Earth in 1835 and died in 1910, the year of its next return. In his own words:

Mark Twain

“I came in with Halley’s Comet in 1835. It is coming again next year, and I expect to go out with it. It will be the greatest disappointment of my life if I don’t go out with Halley’s Comet. The Almighty has said, no doubt: ‘Now here are these two unaccountable freaks; they came in together, they must go out together.” Mark Twain

The day Christmas fell from the sky

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A fragment of the Barwell meteorite which fell on Christmas Eve. Part of the specimen is covered in fusion crust. Credit: Eric Hutton

45 years ago on December 24, 1965 at 4:20 p.m., an early Christmas present fell from space and surprised the residents of the small town of Barwell, England. A huge fireball from the south-southwest streaked across the English skies and initially broke into pieces at an altitude of 25 miles and then shattered again at a lower altitude over the town. Some described the fireball as brighter than the sun. Meteorite fragments showered Barwell, landing in yards, streets and even smashing through a factory roof. One resident noticed a dent in the hood of his car and a fresh, white-colored stone of six to seven pounds on the ground nearby. According to Eric Hutton’s UK and Ireland Meteorite site, one small piece is reported to have gone through a window and landed in a plant pot. Fortunately, no one was struck or hurt by the many fragments.

Chondrules from the Bjurboele meteorite, similar to Barwell. Credit: Wikipedia

All told, at least 97 pounds of space rocks were recovered. When the main pieces were reassembled like a puzzle into one piece, the rock was about the size of a Christmas turkey. The meteorite was named Barwell after the town in which it fell, and looks for all the world like chunks of concrete coated with a thin black fusion crust of rock melted by the heat of atmospheric entry. Looking more closely into the Barwell meteorite, you’d notice small glassy spheres embedded in the gray matrix. These are chondrules (KON-drools), and they’re common in many of the stony variety of meteorites. Chondrules take us back more than four billion years in solar system history to the time of the sun’s formation. Dust and gas  surrounding the nascent sun was heated to the melting point by either lightning-like discharges or shock waves within the gas, causing it to congeal in the weightlessness of space into billions of tiny spheres composed of the minerals olivine, pyroxene as well as grains of iron-nickel and other minerals. These unlikely “seeds” would eventually gather together under the action of gravity to form the planets and their moons.

Material that didn’t go into planet-making was either ejected into distant space or became the asteroids and comets. Long ago, a collision between asteroids released fragments of both into space, one of which eventually made its way to Earth as the Barwell meteorite. A meteorite then is not only a chip from an asteroid but a time capsule from the dawn of the solar system.

The moon rises to the right of Leo the Lion's brightest star Regulus tonight. It also forms a long, flattened triangle with Procyon (PRO-see-on) in Canis Minor the Lesser Dog and Sirius in Canis Major the Greater Dog. Canis Minor has only two stars that form its basic outline. See if you spot it. The map shows the sky facing east-southeast around 10 p.m. Created with Stellarium

Those with clear skies tonight can revel in the winter stars filling up the eastern sky. The waning gibbous moon will partner up with Leo’s brightest star Regulus, when they rise around 8:45 local time. If you’re in the mood for a game of connect-the-dots, the moon forms a big triangle with the stars Procyon and Sirius far to its right. I’m willing to bet you’ll have no problem seeing the entire little dog constellation. We’ll check in on the Big Dog in another blog.

Send holiday greetings to an astronaut near you

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Wearing a Santa Claus hat, NASA astronaut Scott Kelly, Expedition 26 commander, poses for a holiday photo near Christmas decorations in the Unity node of the International Space Station. Credit: NASA

Looks like the Expedition 26 crew aboard the International Space Station is getting into the holiday spirit. You can make their close quarters a little brighter this week by sending the astronauts an e-mail postcard. Just click HERE, select a card, write your message on the back and hit the send button. I sent mine along earlier this morning. It felt good to make a small connection with the crew that’s been flying 220 miles over our heads for days.

They’re busy with science experiments this week, while the rest of us are hurrying to wrap gifts or finish up our Christmas shopping. Looking for a last minute budget gift? Why not download a quality pdf file of the 2011 International Space Station calendar? It features tons of great pictures of life aboard the station, scenes of Earth and important milestones of the space program. If you’re really serious about quality, you can even download the 74 MB version and have a local printer make a high-gloss version.

The 2011 International Space Station calendar. Make a copy on your color printer. Credit: NASA

With Santa Claus coming later this week, you’d think he’d chuck the reindeer and sleigh and cut a deal with the space station for Christmas present delivery. The station zips around the Earth at 17,500 mph, circling the planet every 90 minutes. Far more efficient than a sleigh and protected against the elements to boot. With the help of the crew, Santa could get the job done overnight while enjoying the pleasures of weightlessness. I know there are a few details to consider, but hey, they’re just details.

The space station will be making easy-to-catch evening passes over the region beginning Christmas Eve with a brief appearance in the southwestern sky. Watch for a brilliant “star” moving west to east. Though the sky is dark for us, the station is still lit by sunlight, because it’s many miles overhead. We see a similar effect when the tops of trees or mountain peaks catch the last remaining rays of the sun, while we stand in shadow in the lowlands below. All times below are Central Standard. For times for your town, log in to the Heavens Above website click HERE and type in your zip code.

* Friday Dec. 24 beginning at 6:36 p.m. Low, brief pass in the south-southwest.
* Sunday Dec. 26 at 5:53 p.m. Low but decent pass across the southern sky. Bright!
* Monday Dec. 27 at 6:19 p.m. This one will be brilliant and speed directly above Jupiter before fading into Earth’s shadow. A cool show!
* Tuesday Dec. 28 at 5:11 p.m. Across the south again.
* Wednesday Dec. 29 at 5:36 p.m. Brightest flyby of the week high in the south.
* Thursday Dec. 30 at 6:03 p.m. across the north-northwest.
* Friday Dec. 31 at 4:54 p.m. Brilliant pass high in the south. Second shorter pass in the northwest at 6:30 p.m.

While total lunar eclipses like Tuesday’s don’t happen often enough, there’s one place in the solar system where they’re routine and easy to see from Earth — Jupiter. Its four bright moons are constantly circling the planet, passing in front, in back and into its mighty shadow. When a moon moves into Jupiter’s shadow, it slowly fades and disappears for a while. Later it emerges from the shadow and slowly swells to its original brightness over a span of several minutes.

It's fun and easy to watch eclipses of Jupiter's moons. Tonight Ganymede returns to view shortly after 7 p.m. Central time after being in eclipse. The views show Jupiter and moons in a small telescope with the south direction up. Created with Chris Marriott's SkyMap software.

Tonight small telescope owners can watch as the moon Ganymede emerges from eclipse. Here’s how to prepare. If your scope is normally stored in the house, bring it outside and let it cool down for at least 15 or 20 minutes so the mirror, lenses and tube don’t radiate heat and distort the view. Be sure to keep your eyepieces inside and warm, otherwise they’ll fog over when you put your eye up to them for a look.

Start looking no later than 7 p.m. Central time, when you’ll see only three moons – Europa on the one side of the planet and the pair of Io and Callisto on the other side. Keep your eye on the pair and watch as Ganymede materializes from the darkness to join them. By 7:09 the eclipse is over, and Ganymede will have returned to its usual brilliance. Not only that, but the duo will have become a trio!

Crazy halos plus Jupiter plays tag with Uranus

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A corona forms around the moon last night as clouds pass by. Photo: Bob King

As if to make up for its absence during the recent total lunar eclipse, the moon threw sky watchers a bone last night with a splendid show of color and clouds. Ever-changing colorful coronas ringed the moon as low clouds from Lake Superior tore across its face. A corona is a little colored disk centered on the moon or sun, usually bluish-white in the middle, fringed with red and surrounded by a bluish-green disk. It resembles a colored  bulls-eye of light.

Coronas form when very fine water droplets or ice crystals in clouds diffract light from the sun or moon. The droplets are so tiny, they’re similar in size to the waves of light itself. Light waves scatter off the droplets, and like waves in a pond, cross through one another. Where two wave crests meet and reinforce each other, a bright fringe or circle forms. Where a trough and a crest meet, a dark fringe is created. Each color in white light is diffracted a little differently by the droplets, creating a series of small colorful rings of varying brightness. Red light is diffracted to the outside of a corona, while blue fills the space in between. Click HERE to see photos of a spectacular corona from last year.

Last night's weird halo around the moon. It was thinner than usual and oval-shaped instead of circular. Photo: Bob King

You’ve probably seen a few coronas before but may not have been aware of them. I’m guessing you’ve probably also seen a ring around the sun or moon called a halo. These form when pencil-shaped ice crystals in high cirrus or cirrostratus refract or bend light into a circle with a radius of 22 degrees – that’s about the width of two fists at arm’s length.

In between last night’s coronas, a halo made an appearance for a minute or two and then disappeared. I finally managed to get my camera out and catch one image of it. Take a closer look at the photo above. Halos are almost always circular, but this one is squashed – longer left-to-right than top-to-bottom. I noticed this with my eye as well. It was also unusually thin in parts unlike a typical halo. Anyone have any idea what might have caused this? I’ve looked and can’t find an answer – yet. At the time the picture was taken, low clouds were passing by and light snow was falling.

These photos show the two opposite hemispheres of Jupiter. While the South Equatorial Belt (SEB) is still not nearly as dark as the north belt, it's visible now in 4-inch and larger telescopes. The SEB is thicker and and pitched at any angle in one hemisphere (left), but "pencil thin" in the other, where is passes under the Great Red Spot (right). Credit: Gary Walker (left) and Efrain Morales.

Winter is a great season for halos, coronas, light pillars and other sky phenomena involving ice. It’s also still prime time for Jupiter watching. If you’ve been following the planet through your telescope, you may have already seen the newly-returning South Equatorial Belt, one of two prominent dark clouds belts that stripe the planet’s face. The dark plume that marked the beginning of its return in fall has evolved into a complete belt visible all around the planet. Incredible to see how such enormous features on Jupiter can change in a relatively short period of time.

By good fortune, Jupiter is passing Uranus over the next few weeks. During that time, both planets will be easily visible near one another in the same binocular field of view. The stars shown are 20 Piscium and 24 Piscium, both about the same brightness as Uranus. Jupiter's position is shown weekly through Jan. 12. Uranus moves much more slowly, traveling only the length of the arrow from Dec. 22 to Jan. 12. Created with Chris Marriott's SkyMap software

With the moon now rising later each night, we’re once again entering a period of dark skies, perfect for enjoying a starry sky and seeking interesting celestial objects. One of them is the planet Uranus, and you don’t need a scope to see it. Any pair of binoculars will do the trick thanks to Jupiter being in the neighborhood. The map above shows the motion of both planets in the next few weeks. Right now they’re less than 1 1/2 degrees apart and will be closest on the night of January 3 at just half a degree.

Go out at nightfall (around 6-6:30 p.m. for the northern states) and point your binoculars at that super-bright “star” high in the southern sky. Yep, that’s Jupiter. Look to the planet’s upper left for a “star” of similar brightness to 20 and 24 shown in the map. Congratulations – that’s Uranus, the 7th planet! Though they appear close, Jupiter is 460 million miles away while Uranus is another 1.5 billion miles beyond that. If you have a telescope, you can star hop your way to Uranus from Jupiter. A magnification of about 100x will show its tiny, pale blue disk.