Will Comet L4 PANSTARRS live up to expectations? A reality check

Comet C/2011 L4 PANSTARRS passes near the globular cluster NGC 6541 on the morning of Jan. 16, 2013 as photographed from Castlemaine, Victoria, Australia. The comet measures about 2 arc minutes in diameter with a 7-minute long tail. Click to see more southern comets. Credit: Michael Mattiazzo

Sometimes that shiny new phone or car doesn’t quite live up to expectations, but we often  overlook their deficiencies and make our peace. We may have to do the same with Comet L4 PANSTARRS.

Observers in the southern hemisphere have watched the comet closely since it emerged from the solar glare last month. It’s presently loping along through Corona Australis the Southern Crown and visible shortly before dawn for those living down under. Not too many months ago, PANSTARRS was forecast to reach a brilliant magnitude 0 (equal to the star Vega) come early March this year. In recent weeks however, the comet has been lagging.

Amateur astronomers have noticed that its rise in brightness has been slowing down or plateauing of late. As of Jan. 19, 2013 the comet is a small, dense fuzzball of about magnitude 8 with a short tail pointing west. Binoculars show it as a dim glow.

With less than two months to go before the “big show”, this lag has made some ardent comet watchers revise their expectations of just how bright PANSTARRS will become.

Lightcurve of Comet C/2011 L4 PANSTARRS. Each black dot represents an observation of the comet. The bottom line (axis) shows time, the vertical axis, brightness. PANSTARRS is clearly getting brighter over time but not as fast as expected. Credit: Seiichi Yoshida

Seiichi Yoshida, a Japanese amateur astronomer who maintains the excellent and most useful Weekly Information about Bright Comets site, originally pegged the comet at magnitude 0 in March but has now revised his lightcurve (graphical representation of a comet’s rise and fall in brightness) to show PANSTARRS topping out closer to magnitude 3 at best. His estimate is based upon past as well as the most recent observations.

Comet L4 PANSTARRS photographed on Jan. 19, 2013 with a 200mm lens and time exposure. Credit: Rob Kaufman

If this holds true, what does it mean for comet watchers? A magnitude 3 comet is 15 times fainter than one shining at mag. 0. While still visible with the naked eye, such a comet would not be a visual spectacle. Given that PANSTARRS will be brightest when relatively near the sun in evening twilight, it would appear faint without optical aid, but still be a stirking sight in binoculars and telescopes.

Of course this could change again, so I wouldn’t get too worried yet. Comets are wonderful to follow in part because of their unpredictability. L4 PANSTARRS may yet have a few tricks up its sleeve. Stay tuned for more updates in the coming weeks.

Bitter winter weather conjures visions of Saturn’s moon Titan

Saturn’s moons Titan (larger) and Rhea area a study in contrasts. Rhea is icy, airless, crater-gouged and 950 miles across. Titan is 3,200 miles in diameter (about half again as big as our moon) and enveloped in a dense atmosphere of nitrogen with a haze of hydrocarbons. The orange color comes from tar-like substances that form when methane is bombarded by ultraviolet light from the sun. Credit: NASA / JPL / Space Science Institute

We’ve got bitter cold weather on the way here in Duluth, Minn. with highs predicted around -7 F (-21 C) and lows at night of -20 F (-29 C). What better time to drop in on an even colder place, Saturn’s largest moon Titan. There the average daily high is 290 below zero (-179 C). In those frigid conditions, gases like ethane and methane, of which this moon has an abundance, rain down from the clouds and pool into hundreds of lakes, rivers and seas. From an orbiting satellite, you’d think you were looking at an aerial view of northern Minnesota.

Radar image from NASA’s Cassini orbiter showing a network of lakes in Titan’s northern hemisphere.  Titan’s atmosphere, which is about 95% nitrogen and 5% methane (natural gas) gives the moon a surface pressure 1.6x that of Earth. Credit: NASA/JPL

With a surface pressure 1.6 times greater than Earth, Titan’s atmosphere is thick enough to allow liquid hydrocarbons to exist on its surface. It’s the only known body aside from Earth with great quantities of exposed fluids. As for water ice, yes, Titan has that too, but it’s as hard as rock in such a brutal environment.

How about a swim in Titan’s Sea of Ligeia? This body of liquid hydrocarbons (ethane and methane) with a surface area bigger than Lake Superior, is located in Titan’s Arctic latitudes, has been artificially colored blue. Rivers of methane have carved many channels around its periphery. Credit: Antoine Lucas, Oded Aharonson & The Cassini Radar Science Team, Caltech/JPL/NASA

A new paper by scientists on NASA’s Cassini mission finds that blocks of hydrocarbon ice might dot the moon’s lakes and seas. Their presence is inferred by mixed readings of the lakes’ reflectivity. This is an interesting premise since solid methane ice is denser than the liquid variety and would be expected to sink. But scientists discovered that methane ice will float if the temperature is below the freezing point of methane (-297 F) and the ice contains at least 5% air absorbed from Titan’s atmosphere. Click HERE to read more on the topic.

Titan descent video. At the end at touchdown, you’ll see the shadow of the parachute – amazing!

Eight years ago this week, the European Space Agency’s battery-powered Huygens (HOI-gens) probe entered Titan’s atmosphere after departing the Cassini “mother ship” 3 weeks prior. Huygen ejected its back shell and heat shield and floated down by parachute through the moon’s orange haze. Two and a half hours later it made a slippery-slidey touchdown on the surface. Scientists had hoped it would land in an ocean, since it was made to float, but instead the probe struck terra firma (Titania firma?).

The Huygens probe landed on a soft, sandy riverbed. The rocks you see are most likely made of water ice. Credit: ESA/NASA/JPL/University of Arizona

On the way down, Huygens transmitted pictures of its descent as well as photos from the surface. Networks of streams were seen from the air; on the ground, eerie ice boulders are visible near to far under an orange sky. If there were ever a place you’d call alien, Titan would be it.

I expect once the cold sets in, all the extra clothing we vulnerable humans will don will give the place a similar otherworldly look. Cold weather and plenty of atmosphere – two things Titan and Duluth have in common. Maybe we should consider starting a “sister planet” program.

Here are a couple more videos of Huygens’ descent to Titan including one where you can heard winds buffeting the probe and another showing a brand new animation re-creating the craft’s final descent and peculiar landing. Enjoy!

Simulation of how the probe landed based on data sent back by Huygens.  

The winds of Titan – listen to the sound

Pint-sized auroras possible this weekend Jan. 18-20

Jarno Pääkkönen of Finland took this photo of a very colorful northern lights display Thursday morning, Jan. 17, 2013 in Kontiolahti, Finland, latitude 62.7 degrees north. Details: Canon 5D Mark III camera, 20-25 seconds at f/4 and ISO 2000. Click photo to see more of his work.

A heads-up for all you aurora watchers out there. The NOAA space weather forecast  calls for a 30 percent chance for minor geomagnetic storms tonight Jan. 18 through the 20th. That means there’s a small possibility for auroras in the northern U.S. and a much better one for Arctic regions.

Thomas Kast, who also hails from Finland, shot this photo the same night near Rokua, Finland. “Northern lights are never boring!” he says. Kast had to walk through deep snow in -16 F temperatures to get the shot he wanted. Click to see more photos on his Facebook page.

The cause behind the next expected wave is another CME or coronal mass ejection. Similar enhancements in the sun’s wind of subatomic particles have been responsible for recent, widely-visible auroras across Finland, Norway, Iceland and Canada. We came close to seeing minor auroras in the northern U.S. last night, but the burst of activity that visited the Scandinavian countries earlier in the day had died down by the time darkness cloaked the U.S.

Give a look up if it’s clear this weekend, and if you see the northern lights, drop us a report by clicking on the Comments link below.

Lemmon of a comet slices through the Southern Cross

The Southern Cross, officially named Crux, is tipped on its side in this photo taken off Comet F6 Lemmon on Jan. 18, 2013 local time in Bright, Victoria, Australian by amateur astronomer Rob Kaufman. He used a 134mm telephoto lens setting. The inset photo is a blowup from the main image.

I apologize. I discovered the joy of puns around the age of 13 and have been making family and friends groan ever since. The title refers to Comet C/2012 F6 Lemmon, which has turned out to be anything but.

Lemmon was discovered in March 2012 by A.R. Gibbs during the Mount Lemmon Survey based in the Catalina Mountains north of Tucson. At the time it was spectacularly faint. Not anymore. The comet became much brighter than expected when it first appeared in the morning sky late last fall. I recall it as a big, puffy glow shining at 10th magnitude in my scope one chilly December dawn.

Comet Lemmon’s been on a roll ever since; this week it’s 7th magnitude glowing ball with a bright center easily visible in binoculars from a dark sky. One caveat. The comet’s moving south through the famed Southern Cross in the pre-dawn sky. While you might just catch sight of it from Key West, where it clears the horizon before the start of twilight, southern observers have the edge on this fuzzy blob. From Down Under, Lemmon’s very well placed for viewing between 2 and 4 a.m.

It’s not often a brighter comet crosses in front of the Southern Cross. This compact constellation has three stars (labeled) around 1st magnitude. Acrux is the brightest. The tick marks show the comet’s position each morning (Australian Eastern Daylight Time) starting Jan. 18. Created with Chris Marriott’s Skymap software

Comet Lemmon reaches perihelion – closest approach to the sun – in late March, when it could gleam at 4th magnitude, bright enough to see with the naked eye. Unfortunately, it will be too near the sun to see at that time. We’ll hope that when it slips into a dark morning sky in May, it will still be bright enough to see in a small telescope for observers in both hemispheres.

Comet L4 PANSTARRS in mid-March, Lemmon (perhaps) in May and Comet ISON in fall. Keep the comets coming I say!

You absolutely must see the Winter Hexagon tonight

Check out the six bright stars that connected together form a large hexagon in the evening sky.  It’s up by 7 p.m. local time but best between 8 and midnight. Maps created with Stellarium

There’s a reason the winter sky is so full of sparkling stars. A great many are concentrated around the constellation Orion the form of a gigantic hexagon. How big is it? I made a fist and reached my gloved hand to the sky last night to measure – 6 fists high by 4 fists wide or 60 x 40 degrees. This six-sided figure of celestial real estate reaches from Sirius, low in the southern sky, all the way up to Capella, located nearly overhead from mid-northern latitudes.

What makes these stars special is how bright they are. They all shine at 1st magnitude (or brighter) and appear on the list of the Top 25 brightest stars. Joining the clan are Jupiter, more luminous than any of them, and Castor slightly fainter than the faintest.

Magnitude scale showing the limits of the eye, binoculars and telescopes. Credit: Dr. Michael Bolte, UCO/Lick Observatory

Astronomers use the magnitude scale to measure star and planet brightness. Each magnitude is 2.5 times brighter than the one below it. Aldebaran, which shines at 1st magnitude, is 2.5 times brighter than a 2nd magnitude star, which in turn is 2.5 times brighter than a 3rd magnitude star and so on.

A first magnitude star is 2.5 x 2.5 x 2.5 x 2.5 x 2.5 (about 100) times brighter than a 6th magnitude star.

The bigger the magnitude number, the fainter the star. On the other hand, if an object is really bright, it’s assigned a negative magnitude. Sirius, the brightest star sparkles at magnitude -1.4, Jupiter at -2-2 (currently) and Venus brighter yet at -4.4. The full moon reaches a magnificent -12.7, topped only by the sun at -26.7.

An object’s brightness has much to do with its distance from Earth. Small things like planets, the moon or even an asteroid can look bright if close, while a brilliant supergiant star can appear faint simply because it’s far away.

Photo taken last night Jan. 16, 2013 of the Winter Hexagon and Jupiter about 9 p.m. Photo: Bob King

To get a better appreciation of an object’s true or absolute brightness, astronomers assign it an absolute magnitude, based on how bright it would appear when moved to a distance of 10 parsecs (equal to 32.6 light years) from the sun. When stars are all placed at the same distance, absolute magnitudes show differences in true star brightness.

A parsec is the distance from the Sun to an astronomical object which has a parallax angle of one arc second – parallax second – against the background sky. Parallax, which is measured in arc seconds or tiny fractions of a degree, is the apparent shift of a nearby star against the distant background of stars as seen from either end of Earth’s orbit.

One parsec equals 3.26 light years. Click HERE for a blog I wrote explaining parallax. The main thing to remember is we’re comparing objects at the same distance of 10 parsecs from the sun.

Here are the apparent (what we see with the eye) and absolute magnitudes (in parentheses) of our featured stars::
* Sirius -1.5 (1.4)
* Procyon 0.4 (2.6)
* Pollux 1.1 (0.7)
* Capella 0.1 (0.4)
* Aldebaran 0.9 (-0.3)
* Rigel 0.1 (-8.1)
* Jupiter -2.2 (55)
* Betelgeuse 0.5 (-7.2)
* Castor 1.6 (0.5)
* Our sun -26.7 (4.8)

An illustration of how the Winter Hexagon and neighboring bright stars would appear if all moved to the same distance of 32.6 light years. We would see them at the absolute magnitudes. Notice anything missing?

Right away you’ll see some dramatic differences in intrinsic brightness. Rigel and Betelgeuse, both of which appear more than a magnitude fainter than Sirius to the eye, far outshine all the others. Seen from 10 parsecs, each puts out enough light to cast shadows at night. Why? They’re both extremely luminous supergiant stars. Jupiter, the big shot of the bunch, fades out of sight.

Sirius, only twice as big as the sun, dims to a rather meek mag. 1.4. It’s overtaken by otherwise mild-mannered Castor, a double star with suns 2.4 and 1.9 times larger than our own. How does our sun fare at 10 parsecs? Not so good. At magnitude 4.8, it would blend into the background of faint stars. Unless you looked carefully, you wouldn’t even notice it.

Knowing a star’s absolute magnitude gives us a true picture of a star’s brightness. What’s more, you can derive a star’s distance by comparing its apparent magnitude to the absolute magnitude. Want to have a little fun? Click on the Magnitude and Luminosity Calculator and play around with some of your favorite stars.

Mission control to Curiosity rover: Drill, baby, drill!

Look closely at this photo of the “Sheepbed” locality, taken by Curiosity rover, and you’ll see well-defined veins filled with whitish minerals believed to be calcium sulfate. These veins form when water circulates through fractures, depositing minerals along the sides of the fracture, to form a vein. Scale at top. Click to enlarge. Credit: NASA/JPL-Caltech/MSSS

Curiosity rover has done it again – found even more evidence for soaking, seeping, swirling waters on Mars. We’ve seen earlier images of water-rolled pebbles and sedimentary outcrops, but this week NASA shared a new set of photos from the Yellowknife Bay site showing alternating, thin layers of rock that could only have formed in a stream bed. Other pictures show mineral veins deposited by flowing water in rock fractures. What’s remarkable it how similar these rocks look to their counterparts on Earth.

This set of images shows the similarity of sulfate-rich veins seen on Mars by Curiosity to sulfate-rich veins seen on Earth. The view on the left is a mosaic of two shots from the remote micro-imager on the ChemCam instrument. Credit: NASA/JPL-Caltech

Scientists have been studying Yellowknife through Curiosity’s eyes looking for an ideal spot to test the rover’s drill for the first time. If engineers deem it safe, the rover will inch up to “John Klein”, a flat-lying expanse of bedrock laced with pale mineral veins, and fire up its drill sometime in the next few days. The location is named after former Mars Science Laboratory deputy project manager John W. Klein who died in 2011.

This picture shows inclined layering known as cross-bedding in an outcrop called “Shaler”. Currents mold the sediments into small underwater dunes that migrate downstream. When exposed in cross-section, evidence of this migration is preserved as tilted layers or strata. The bottom of the large outcrop is about 3 feet across. Click to enlarge. Credit: NASA/JPL-Caltech/MSSS

The first powdered rock samples will be used to scrub the drill clean of any earthly contamination. Later samples will be fed into Curiosity’s miniature chem lab to analyze the rock’s mineral and chemical makeup. Thanks to a zap from the rover’s ChemCam laser, we already know one of the veins contains high levels of calcium, sulfur and hydrogen, likely from the mineral calcium sulfate, better known as gypsum.

Not only has the robot returned photos of cross-bedded outcrops (layers of sediments deposited by rivers) and mineral veins, but using the closeup camera, scientists have found grains of sandstone the size of “peppercorns” in other rock formations nearby.

The “John Klein” site in Yellowknife Bay, a broad depression in Gale Crater on Mars. Sometime in the next few days, the rover will use its drill to gather a rock sample. The drill can bore as deep as two inches into rock. Click for large, annotated photo. Credit:

“Still others are siltstone, with grains finer than powdered sugar. These differ significantly from pebbly conglomerate rocks in the landing area,” according to the NASA release. Siltstones were originally layers of mud that were later compressed into rock by geological forces.

All these signs point to a much wetter past on the Red Planet. Pouring over the new pictures, it doesn’t take much imagination to envision the floor of Gale Crater crossed by streams and dotted with small lakes. For water to be stable on the surface of Mars long enough to build the rocks we’re now finding, the planet must have had a much thicker atmosphere and warmer temperatures in the past. A denser atmosphere provides pressure needed to prevent water from boiling away.

Curiosity photographed a transparent mineral grain measuring a couple millimeters across embedded in coarse-grained sandstone. Some Internet users have dubbed it “the Mars Flower”. Credit: NASA-JPL/Caltech

Transport yourself to a remote time when the brown Martian sky was blue and the air almost humid. At your feet a stream swirls along, carrying away tiny pebbles and grains of sand. While oxygen may only have been present in trace amounts in the ancient Martian air, you could listen to the sound of running water and maybe even hear one of Mars’ many volcanoes rumbling in the distance. Tell me this wasn’t a world ripe for microscopic life.

Sun blows Earth a kiss – will she blush?

Three views over 2 1/2 hours of a coronal mass ejection or CME as it burst off of the sun headed for Earth this morning Jan. 13, 2013. The images were captured by NASA’s Solar Terrestrial Relations Observatory (STEREO). Credit: NASA/STEREO

The sun hurled a coronal mass ejection (CME) in Earth’s direction this morning at 1:24 a.m. (CST). This proton-electron particle spray may reach us within 1 to 3 days and possibly make the Arctic sky blush with auroras. We’ll have to wait and see.

Since this CME left the sun at only 275 miles per second, it’s not likely to kick up a big storm. The biggest blasts can send particles our way at nearly ten times that. If they succeed in connecting with Earth’s magnetic envelope, the magnetosphere, electrons and occasionally protons spiral down along magnetic field lines into our atmosphere to produce auroras. We don’t have to worry about these guys hitting us directly on the ground; we’re protected by the planetary magnetic field and the air above us.

Saturn’s tiny moon Daphnis (the point of light) clears the 26-mile-wide Keeler Gap, named after 19th century American astronomer James Keeler, in Saturn’s rings. The gravity of the moon also creates the ripples seen along either side of the vacancy. Credit: NASA/JPL-Caltech SSI

One of my favorite things to do is dig through image archives looking for gems to share. A recent photo of Saturn’s 5-mile-diameter moon Daphnis raising sawtooth-like waves in Saturn’s Keeler Gap caught my eye. The picture, taken by the Cassini spacecraft last August and released in late December 2012, shows a lovely series of ripples on either side of the Keeler Gap, a debris-free zone about 26 miles wide near the outer edge of Saturn’s A-ring.

Closeup of Daphnis and its gravitational wake photographed by Cassini on July 5, 2010 from a distance of 45,000 miles.  Click to enlarge. Credit: NASA/JPL/SSI/ color composite by Gordan Ugarkovic

As it circles the planet on an inclined orbit, Daphis’ gravity tugs on the icy ring particles to clear a gap and create the ripples. The rings are only about 33 feet thick despite their vast extent and consist primarily of individual chunks of ice in their own slightly different but unique orbits about the ringed planet.

Although difficult to see in the picture, the ripples rise up about 1 mile above the ring plane. Notice there are two sets. Material along the inner edge of the gap orbits faster than the moon, so that the ripples precede Daphnis in its orbit. Material on the outer edge moves slower than the moon, creating a set of trailing waves.

Nature has many sculptors and tools with which to fashion the most delightful of cosmic structures. Put a smidge of a moon in the right place and it’s not long before something marvelous happens.

Supersonic bullets etch tunnels of light in Orion Nebula

Supersonic bullets of iron- rich gas tunnel through the outskirts of the Orion Nebula in this photo made on December 28, 2012. The nebula lies about 1,350 light years from Earth. Click to enlarge. Credit: GeMS/GSAOI Team, Gemini Observatory, AURA

If you haven’t seen this picture yet, I’m glad you are now. Amazing, isn’t it? What you’re staring at are blue “bullets” of iron-rich gas shot out from growing stars inside the Orion Nebula. The bullets measure some 70 billion miles across (10x the size of Pluto’s orbit) and create tubular wakes in the nebula’s dust and gas as they plow through hydrogen gas, setting it aglow. Some of traceries are 1/5 of a light year long.

Most stars not only radiate heat but also lose material from their hot surfaces in winds. We’re familiar with the sun’s solar wind, a tenuous stream of protons and electrons that flows away from our star at a speed of around 300 miles per second. The sun loses 1/100,000,000,000,000th (that’s one-trillionth) of its mass per year because of its windy ways.

The massive and clumpy stellar wind blasted by the aging supergiant star in the center of the Crescent Nebula in Cygnus. Click for details and more photos. Credit: NASA/ESA

Massive stars are extremely hot and brilliant. The power of their energetic light accelerates material off the star with gale force winds. While the sun will only lose about .01 percent of its material during its expected 10 billion year lifetime, giant stars, like those powering the bullets, slough off 1/100,000th of a sun’s worth of mass every year. During its brief life, a massive star can lose up to half the material with which it started.

Astronomers used the 8.1-meter (319-inch) Gemini South telescope in Chile to snap the first pictures of the bullets in 2007 and then again on December 28, 2012 with an adaptive optics setup that greatly reduced atmospheric turbulence. The result: super-sharp images. If you study this animation of before and after photos, you’ll see subtle but real changes in the structure and position of the pillars and knots. The universe sits still for no one – everything’s on the move! While we know that intuitively, seeing it is quite another thing. Read more about the photos and science behind the story HERE.

The Orion Nebula is found in a short line of stars called “the Sword” below Orion’s three belt stars. This view shows the sky facing southeast around 8 p.m. local time. Photo: Bob King

While you and I can’t see the bullets through our toddling telescopes, we can see where all the action’s happening – the Orion Nebula. The nebula is faintly visible with the naked eye as a fuzzy spot in Orion’s Sword, a vertical stack of three fainter stars below Orion’s famous belt.

Consisting of a 24-light-year-wide spread of dust and gas arrayed in glowing pink and green tendrils, the Orion Nebula is nothing short of a huge factory cranking out stars like loaves of bread at a bakery.

Denser knots of material with the nebula succumb to the force of gravity and collapse into brand new suns. Many are small and lost in the nebula’s misty folds, but some are supergiants with windy temperaments.

Little more than a wisp to the naked eye, the Orion Nebula easily shows a cocoon-like shape in binoculars from suburban and rural skies.

The Orion Nebula in its full glory. Clouds of hydrogen gas fluoresce red from radiation emitted by the central star cluster (overexposed area) called the Trapezium. Click to enlarge. Credit: NASA/ESA

The real fun comes in the telescope. I’d guess I’ve looked at this cosmic wonder at least 500 times during my life. There’s simply no good reason not to dial it up for a view during fall, winter and even early spring. When it comes to winter deep sky objects, the Orion Nebula’s makes for tasty, low-hanging fruit.

We see the Trapezium in this closeup view. Notice how the small cocoons of dust and gas, which contain developing stars, point away from Theta. Their gases are being stripped off by powerful stellar winds. Credit: NASA/ESA

Not only is it loaded with gaseous detail in the shape of arms, wings, petals and pleats, but at its center shines the exquisite Trapezium, a compact star cluster arranged in a trapezoid. The brightest, largest and most luminous of the quartet is Theta-1 Orionis. Its massive outpouring of ultraviolet light makes it the nebula’s primary illuminator. Take away Theta-1 and there wouldn’t be much left to see. Theta also blasts strong winds into the surrounding nebulosity, stripping away material from stars in the birthing process. These nasty habits guarantee a short life; Theta-1 burns its fuel so rapidly it will likely explode as a supernova in just a few million years.

While it may look like a quiet, fuzzy place on a still winter night, the Orion Nebula is teeming with activity. Have a look sometime and it won’t be hard to imagine those crazy cosmic bullets whizzing about.

Prodigious sunspot group gets our attention

Sunspot region 1654 is big enough to show in a 400mm telephoto lens this morning  Jan. 14, 2013.  Thanks to a layer of clouds that filtered the sun’s light to a safe level, I could take a few quick photos. The spots are lined up horizontally above center. Photo: Bob King

I wrote about the current monster sunspot group in yesterday’s blog, but not until I saw with my own eyes through a filmy layer of clouds this morning did I realize how impressive it really is. The region, named 1654, stretches some 112,000 miles or approximately 14 times the diameter of the Earth across the sun’s northern hemisphere. With a safe solar filter, I could make out the two biggest spots.

The sun photographed by the orbiting Solar Dynamics Observatory at 11:30 a.m. CST today Jan. 14, 2013. Credit: NASA

Sunspots are dark because they’re several thousand degrees cooler than the sun’s visible surface called the photosphere. The contrast makes them appear greyish-black. Powerful magnetic energy concentrated in sunspots insulates them from the surrounding 11,000 degree heat by blocking the flow of hot gases from the sun’s interior. Less gas means less heat and cooler spots … if you call 8,000 degrees cool.

Although region 1654 continues to flare, no storms are expected to hit Earth for the time being. Just the same, the solar wind has been strong enough on its own in the past 24 hours to ignite northern lights displays across the Arctic. I’ll post updates regularly if a geomagnetic (auroral) storm should blow up.

By the way, ever since I saw the movie October Sky I’ve liked the word ‘prodigious’.

Thin crescent moons and space station swings, these are a few of my favorite things

The crescent moon greets sky watchers tonight in the western sky during twilight. Binoculars will show Mars very low above the horizon about an hour after sunset. Created with Stellarium

Two of our favorite sky objects are back. A fingernail crescent moon will scratch the sky at dusk and the space station begins another series of swing-bys  at  dawn.

Watch for the moon in the southwest during evening twilight. If you’re game for a challenge, use binoculars to find dim Mars about 7 degrees directly below the moon. Think of Curiosity up there poking around the rocks of Gale Crater in Yellowknife Bay. Can you believe it’s been there for 161 days already?

This image from the Mars Hand Lens Imager (MAHLI) shows the patch of rock cleaned by the first use of the rover’s Dust Removal Tool (DRT) on Jan. 6, 2013. Click to enlarge. Credit: NASA/JPL-Caltech

Last week the rover used its motorized, wire-bristle brush for the first time to dust off a rock in preparation for close-up inspection by the hand-lens imager and Alpha Particle X-ray Spectrometer (APXS). The APXS analyzes the elements that compose the rock by bombarding it with alpha particles (helium atoms) and X-rays and measuring what scatters back. Each element gives off its own distinctive energy fingerprint.

Expedition 34 crew members photographed an extensive blanket of stratocumulus clouds as they flew over the northwestern Pacific Ocean on Jan. 4, 2013. The cloud pattern is typical for this part of the world. The low clouds carry cold air over a warmer sea. Click to enlarge. Credit: NASA

Morning sky watchers again have the pleasure of tracking the International Space Station (ISS), now beginning a fresh series of passes before sunrise. Winter mornings make watching the space station easy compared to summer. With the sun rising so late, you can look for the station when you step out to pick up the paper or walk the dog. No getting up at 4 or 5 a.m. like you did during the summer months with its early sunrises and even earlier twilights.

The times below are for the Duluth, Minn. region. Check out times for your town at Spaceweather’s Satellite Flybys page or log in to Heavens-Above, where you can print out cool maps of the space station’s path in the sky. Look for the ISS to first appear in the west and travel east; a typical pass takes about 5 minutes.  It looks like a brilliant, steady yellow star on the move.

* Tomorrow Jan. 14 beginning at 6:55 a.m. High pass across the northern sky. Brilliant at magnitude -3.2
* Tues. Jan. 15 at 6:07 a.m. when it suddenly leaves Earth’s shadow in the western sky in Leo and travels across the top of the sky headed east. Brightest pass of the week at mag. -3.4
* Weds. Jan. 16 at 6:51 a.m. Nice pass across the northern sky
* Thurs. Jan. 17 at 6:03 a.m. Appears  suddenly out of Earth’s shadow halfway up in the northwestern sky moving east.
* Fri. Jan. 18 at 6:48 a.m. Full pass across the northern sky
* Sat. Jan. 19 at 6 a.m. First appears out of Earth’s shadow near the North Star moving east.

Closeup of the large sunspot region 1654 taken at 9 a.m. CST this morning Jan. 13, 2013 by NASA’s Solar Dynamics Observatory. Solar storms or flares occur when powerful magnetic energy stored in the spots is explosively released.  Click to enlarge. Credit: NASA

The sun’s been looking pretty hot this past week. Lots of flares, including a few rated as moderately powerful M-class storms, have been popping off in the large sunspot group 1654. I see today that the Kp index, an indicator of magnetic activity around the Earth, is starting to climb again – just a little. The space weather forecast doesn’t predict any auroras minor or major in the next three days, but that could change if 1654 continues firing off flares as it rotates to face the Earth more directly.