Aurora alert – minor storm in progress tonight July 9-10

A pretty series of rays pokes out from behind light-polluted clouds in the northern sky around 11 p.m. tonight July 9. Credit: Bob King

A small auroral display is in progress here in Duluth, Minn. with a series of faint rays now and again dappling the northern sky. Might want to keep your eye on it. The Kp index, a good indicator of auroral activity, is currently at “5” or minor storm level. A coronal mass ejection from the sun that blew by Earth this afternoon may be the reason for this uptick.

The auroral oval map indicates auroras potentially visible across northern Minn., Wis, Mich. and N. Dakota as of 11:30 p.m. CDT. To best see a northern lights display, find a site with a dark sky to the north and cross your fingers the lights continue. Good luck!

Road trip! Curiosity rover heads for the hills

Mt. Sharp in Gale Crater looms five miles in the distance in this photo taken on July 8. Credit: NASA/JPL-Caltech

NASA’s Curiosity rover has set its sights for the fertile layers of Mt Sharp. You know the place – it’s that big hump on the horizon seen in many of the rover’s photos. The 3.4-mile-high (5.5 km) mountain has beckoned like a tempting Shangri-la for almost a year. Curiosity will roll across rocky terrain and a swath of potentially perilous sand dunes to reach the mountain’s base in a journey expected to take from 9 months to a year.

The photo at left is a closeup of chunk of ancient, pebble-riddled streambed on Mars with a particularly round pebble highlighted. It’s just under 1/2 inch (1 cm)across. At right, rocks are rounded into pebbles by the action of water in Amity Creek in Duluth, Minn. Credit: Bob King

After landing in August, rather than heading straight for the mountain, the car-sized rover detoured for more than six months to explore the Glenelg area, a region once braided by ancient streams. Curiosity found sedimentary rocks – desiccated riverbeds – chock full of rounded rocks shaped by waters cascading down the walls of Gale Crater several billion years ago. What a sight that must have been.

A rock in Yellowknife Bay is made of fine-grained sediments likely deposited under water. The rock was then fractured. Neutral pH waters deposited calcium sulfate, a form of gypsum, filling the crack.  Credit: NASA/ JPL-Caltech

Rocks found in neighboring Yellowknife Bay area were found to contain clays that formed in the presence of water that was neither too alkaline nor acidic. Just right for life.

Likewise, detailed analysis by Curiosity’s Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments found elements essential for life to thrive and derive energy from its environment. Carbon, nitrogen, hydrogen, oxygen, sulfur and phosphorus all turned up. Those elements cover about 99% of what makes you you and me me.

The many layers of Mt. Sharp as seen from orbit. The 3.4-mile-high (5.5 km)mountain is really a huge deposit of materials similar to the layers in the walls of the Grand Canyon. Some are probably sedimentary, laid down by rivers or deposited in shallow seas; others possibly volcanic ash. Credit: NASA/JPL-Caltech

Indeed, the mission’s main science objective – finding evidence for a wet environment that had the conditions favorable for microbial life – has already been accomplished. But it’s not time to go home yet. After photographing, drilling and laser-zapping near its home turf, on July 4 Curiosity drove 59 feet (18 m) toward its new target; on July 7, a second drive added another 131 feet (40 m).

Mars Rover Curiosity looks back at wheel tracks (right foreground) made during the first drive into the “Glenelg” area 7 months ago. It’s now headed to Mount Sharp. Credit: NASA/JPL-Caltech

The many-layered base of Mt. Sharp are like pages of an ancient book to be turned over one at a time and studied for more clues about how Mars, once clearly a wet world friendly to life, turned dry, cold and hostile.

Hubble spies Comet ISON on the move

Comet ISON, discovered by two amateur astronomers last September, quietly streaks through space in this time-lapse sequence made in May.

I thought you’d like to see this short video of the year’s most anticipated comet. The 43-minute time-lapse, compressed to just 5 seconds, was made back on May 8 when the comet was 403 million miles from Earth between the orbits of Mars and Jupiter. During the sequence, ISON travels 34,000 miles (55,000 km) or about four Earth diameters at a clip of 48,000 mph (77,000 km).

The particulars on Comet ISON when photographed by the Hubble Space Telescope on May 8, 2013. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

In the video we see ISON’s bright “false nucleus” within which spins the comet itself, a 3-mile-wide (5 km), misshapen hunk of dust-impregnated ice. Sunlight vaporizes the ice, releasing the dust and brushes it back to form the tail.

ISON will gradually brighten in the coming months, reaching naked eye visibility sometime in early November. For a complete and updated forecast on what to expect, click HERE.

Distant quasar exposes a hungry galaxy’s snacking habits

This artist’s impression shows a distant galaxy that formed just two billion years after the Big Bang, in the process of pulling in cool gas (shown in orange) from its surroundings. Astronomers have been able to find out a lot about the object by taking advantage of a rare alignment of the galaxy and more distant quasar (bright object left of the central galaxy). Credit: L. Calcada/ESA/AOES Medialab

Like a guy munching chips in front of the TV, galaxies increase their girth by snacking on what they find handy. That’s the finding of a multinational team of astronomers in a recently published paper on the eating habits of galaxies.

Using the European Southern Observatory’s Very Large Telescope, astronomers took advantage of a rare alignment of a distant quasar and the foreground galaxy HE 2243-60 in the southern constellation of Tucana the Toucan. A quasar or ‘quasi-stellar radio source’ looks like a faint star but up close what appears as starlight is really matter heated to incandescence as it gets sucked into a supermassive black hole at the center of remote galaxies. Quasars send out radiation of many flavors including visible light and radio waves.

The quasar 3C273 photographed with the Hubble Space Telescope looks like a star and far outshining its host galaxy. When the quasar is blocked with a special occulting disk, the galaxy is much easier to see during a long time exposure (right). Credit: NASA/ESA

More than 200,000 quasars are known and most are extremely distant, upwards of 3 billion light years. Though they appear faint, they’re the most luminous objects in the universe. The brightest, 3C273 in Virgo, shines at just 12th magnitude and looks identical to a star.

Supernovae explosions return materials including gases enriched with heavier elements like nickel, gold and iron to space where they can be recycled into new stars. Credit: ESO

Like everything else in the universe, galaxies are born from great clouds of gas and dust, which they quickly use up manufacturing stars and planets. While some of the matter is recycled into new stars through supernovae and the huff-and-puff of ageing sun-like stars, galaxies need more food to maintain their sparkle.

How do they do it? Gravitational muster. Galaxies pull in cool gas from their surroundings which circles about them like water going down your bathtub drain. Once the gas enters the celestial pinwheel it’s ultimately fashioned into stars through self-gravity, providing twinkling tiki lamps to light the galactic night.

Artist’s impression shows ULAS J1120+0641, a very distant quasar powered by a black hole with a mass two billion times that of the Sun. This quasar is the brightest object discovered so far in the early universe. Credit: ESO /R. Kornmesser

Astronomers have found evidence of galaxies’ gas guzzling habits before, but this time the laser-like beam of the remote quasar QSO J2246-6015 passing through the foreground galaxy allowed astronomers to probe the composition and motion of the infalling gas in unprecedented detail.

The gas clouds absorb narrow segments of the quasar’s beam leaving a pattern of distinctive dark lines – fingerprints as it were – in its light spectrum. Every element and molecule has it own set of fingerprints. Find and measure them and you can determine the composition of everything from stars to asteroids to succulent gas clouds.

“In this case we were lucky that the quasar happened to be in just the right place for its light to pass through the infalling gas. The next generation of extremely large telescopes will enable studies with multiple sight lines per galaxy and provide a much more complete view,” concludes co-author Crystal Martin of University of California Santa Barbara.

Now back to eating more chips.

Get pumped for ‘In Saturn’s Rings’, a stunning million-image flyby video

Click image to see the 2 1/2-minute Vimeo of Stephen van Vuuren’s first efforts at a seamless flyby of Saturn using Cassini images.

South African filmmaker Stephen van Vuuren has a surprise for you. His passion for the spectacular images of Saturn’s rings made by the orbiting Cassini spacecraft since 2004 inspired him to create the short test film Outside In back in 2010. Now he’s back with a bigger, better version In Saturn’s Rings.

Van Vuuren used thousands of images from the Cassini archive to create a strikingly realistic journey through the Saturn system in that early effort. Paired with Samuel Barber’s music Adagio for Strings, a lot of us got goosebumps watching it.

Click to see the railer for the upcoming movie “In Saturn’s Rings” by Stephen van Vuuren

In the new, longer version retitled In Saturn’s Rings, van Vuuren has upped his game with more than a million images and new film techniques to create a high-definition IMAX film set to be released next year. Click on the photo to see the trailer, and be sure you select the ‘original 4K quality’ to revel in its full glory.

Saturn’s largest moon Titan, wrapped in its orange, smog-like atmosphere, floats above Saturn’s ring plane in a frame grab from In Saturn’s Rings. Credit: NASA/JPL

No computer generated images (CGI) were used in the movie, just the real thing. Only the motion was computer generated through zooming, panning, tilting, etc. similar to what you’d see in a PBS documentary. That’s what makes this movie special. And what better celebrity than Saturn to fill a full-dome screen with accompanying concert surround-sound?

Still frame from the Saturn flyby sequence in the film clip. Credit: NASA/JPL

If there was ever a cosmic object that demanded your full visual field, Saturn’s it. The rings span some155,000 miles (250,000 km). If one end of the ring plane were touching Earth, the other end would reach two-thirds the way to the moon. Yet the rings are exceptionally thin, only 30 feet (10 m) thick.

Once completed, the film is slated to run at IMAX theaters, full dome planetariums, museums and select movie theaters. In the meantime, enjoy a taste. More information about the project can be found on the movie’s website.

Aurora alert – minor storm in progress overnight July 5-6

A thick auroral arc simmers in the northern sky in Duluth, Minn. around midnight-12:30 a.m. Saturday morning July 6. The pink glow is light pollution. Credit: Bob King

A suspicious glow in the north tonight proved to be aurora. Right now activity is moderately high – the solar wind has tipped south – and a soft, very diffuse green aurora covers up to 1/3 of the northern sky. Nothing to write home about … yet.

I watched for about 45 minutes from just north of Duluth, Minn. and never saw a ray, but the dawn-like glow was and still is obvious. The auroral oval map indicates this display could be visible as far south as northern Iowa as of 1 a.m. this Saturday morning.

I wanted to post this alert for aurora-watchers in case the show cranks up before dawn.

Mars rovers capture loony moons and blue sunsets

Phobos and Deimos, photographed here by the Mars Reconnaissance Orbiter, are tiny, irregularly-shaped moons that are probably strays from the main asteroid belt. Credit: NASA

Mars has two tiny moons. Phobos, the larger of them, is a spud-shaped object about 14 miles (22 km) across. Deimos (DEE-mohs or DYE-mohs) is a bumpy ball with an average diameter of 8 miles (13 km). Compared to our moon’s 2,159 mile (3,474 km) diameter, these guys are truly small potatoes.

Phobos passing overhead after sunset as seen by NASA’s Curiosity Rover last month. Time-lapse images were taken over 27 minutes.

Both the Curiosity rover and the Spirit and Opportunity rovers have taken time out from staring at the ground to occasionally look up at the moons of Mars at dusk or dawn. This week NASA released a short video of Phobos crossing through the sky after sunset. I like the fresh perspective. Seeing how the Martian sky differs from Earth’s makes that planet feel all the more an alien.

The Spirit Rover captured this transit of Phobos across the sun in 2005. Credit:NASA

If you could stand next to Curiosity and look up, you’d see that Phobos looks considerably smaller than Earth’s moon – only a third as big. Like our moon, it occasionally crosses in front of the sun, an event known as a transit.

While it’s too small to completely eclipse the sun it makes a striking silhouette in the video.

Deimos looks even smaller both because of its smaller size and it’s more than twice as far from the planet as Phobos. To the naked eye, Deimos would look like a brilliant star to everyone but  keen-eyed skywatchers who might glimpse its teensy shape with a little concentration.

95 images of the Sun taken by Curiosity early in the mission were aligned to make this animation of Deimos transiting the Sun. Look closely and you’ll see it spinning.
NASA / JPL / MSSS / Emily Lakdawalla

Because they resemble asteroids in size and composition, many astronomers think Deimos and Phobos were captured by Mars in the distant past. Nowadays they circle the planet in 30.3 hours (Deimos) and 7.6 hours (Phobos). While they’re every bit a moon like our own familiar orb, their behavior in the sky is something altogether different.

Phobos orbits at an average distance of 5,830 miles from Mars. Its extreme closeness to the planet means it moves rapidly across the sky as seen from the ground. Phobos rises in the west and sets in the east, crossing the sky in just 5 1/2 hours. Wait another 5 1/2 and you can watch it rise again in the west. On a long winter night, an astronaut on Mars would see Phobos rise twice and set once!

Deimos, which orbits further from the planet, rises in the east like a normal moon or star, but because its orbital period is so close to that of Mars (24 hours and 37 minutes) it moves very slowly upward from the horizon and doesn’t set in the west until almost 3 days later. One moon’s on steroids; the other putters about as if it had all the time in the world.

Colorized sunset shot by Curiosity’s black-and-white navcam from inside Gale Crater on June 22, 2013. Credit: NASA/JPL-Caltech

Curiosity also snapped a few photos of sunset on Mars on June 22. Martian sunsets and sunrises aren’t quite the visual feast they are on Earth. There’s so much dust suspended in the planet’s atmosphere, the sky glows a monotone reddish brown with a large pale blue aureole surrounding the sun.

True color photo of sunset over Gusev Crater on Mars taken by the Spirit Rover in 2005. Credit: NASA/JPL-Caltech

“The blue color comes from the way Mars’ dust scatters light,” says Mark Lemmon, associate professor of atmospheric sciences and a camera operator on the twin rovers Spirit and Opportunity.

“The blue light is scattered less, and so it stays near the sun in the sky, while red and green are all over the sky. On Earth, blue light is scattered all over by gas molecules, but there are not enough of these on Mars, which has less than 1 percent of Earth’s atmosphere, to accomplish this.”

Aurora encore may follow July 4 fireworks

July 4th fireworks at Duluth, Minnesota’s Bayfront Park. Credit: Bob King

Happy Fourth of July! I hope your day explodes with enjoyment.

Aurora time-lapse

Just don’t go to bed after the fireworks show before checking the northern sky. NOAA’s space weather prognosticators expect a small auroral storm to begin sometime tonight and continue through tomorrow night. There’s a 20% chance we’ll see action at mid-northern latitudes and a 60% chance at high latitudes, where one wonders if any auroras are seen to advantage this time of year. North of about 49 degrees north latitude, twilight lingers all night long during the summer months.

The forecasted northern lights are brought to you by a slower moving coronal mass ejection, a blast of particles from the sun usually caused by the explosive power of a solar flare.

Neighboring sunspot groups 1785 and 1787 photographed this morning with NASA’s orbiting Solar Dynamics Observatory. Credit: NASA/SDO

We may not have to wait too long for the next eruption. Sunspot group 1785, which rotated onto the sun earlier this week, is a large, complicated magnetic mess and harbors the energy to kick out powerful M-class flares. The sun’s rotation will bring it forward to face Earth more directly in the days ahead increasing the chances for more auroras.

M1.5 flare from sunspot group 1787 as it rounded the eastern limb of the sun early on the morning of July 3. Credit: NASA/SDO

Not far behind, sunspot cluster 1787 put on its own fireworks show when it first rotated around the sun’s limb early Wednesday morning, greeting astronomers with a moderate M1.5 flare.

How the sizes of Earth and moon compare to sunspots. Even an Earth-sized spot requires a telescope to see. The leader spot in the group 1785 is at least 3x larger than our planet. Credit: NASA

The big spot in 1785 is now large enough to see with the naked eye using a safe solar filter – I easily spotted it this morning as tiny dark fleck in the sun’s southeast quadrant. Sometimes we forget how big sunspots truly are. What looks like a tiny dot in a small telescope is about as big as the moon; Earth-sized spots are larger but ordinary by solar standards. This morning’s behemoth was easily thrice our planet’s diameter, and the group it belongs to spans some 8 Earth diameters.

A sunspot’s dark tone is deceiving. They only look that way because they’re 3,000 degrees cooler than the 11,000 degree photosphere, the glaring white “surface” of the sun. If we could remove the spots and see them alone against the black backdrop of outer space, they’d be much too bright to look at safely. Their size hints at the true vastness of the sun, an 863,700-mile-wide (1.4 million km) sphere of incandescent gas 4 times hotter than a handheld sparkler.

Delicious Comet Lemmon-cluster pairing; moon greets 7 Sisters at dawn

Comet C/2012 F6 Lemmon cruises by the open cluster NGC 7789 in Cassiopeia last night July 2, 2013. Click to supersize. Credit: Damian Peach

It’s a beautiful thing when two completely different celestial objects pair up. Seen side by side, we can appreciate the unique qualities of each by contrast with the other. Two fine examples stand out this week.

Comet Lemmon, which has been chugging across the sky for months, pulled up alongside the rich star cluster NGC 7789 this week. The cluster is sandbox of pinpoint stars tucked off to one side of the W of Cassiopeia. I’ve been watching the scene the past two nights through the telescope. Last night both comet and cluster shared the same field of view.

Compared to the pointillistic stellar swarm, the comet looked ghostly and ethereal. And to think that one of these belongs to our solar system and the other resides on the far edge of the galaxy at a whopping 7,600 light years from Earth … well, it simply jazzes the brain cells. What can I say?

Then there’s composition to consider. Comets and the sun are made of virtually the same materials – hydrogen (frozen H2O in a comet’s case) and a dusting of carbon, nitrogen, oxygen, silicon and on and on. Yet comets are cold, relatively uncompressed dust. Not the sun. Put enough dust in one place and gravity will eventually crush it into a sphere hot enough to start its innards burning. A star is born. Interstellar dust left by earlier stellar generations is their common bond.

Watch the moon come up below the Pleiades star cluster tomorrow morning. The crescent will be only three days from new moon. This map shows the sky facing northeast at early dawn. Stellarium

Tomorrow morning we’ll see another auspicious duo. The waning lunar crescent rises at dawn below the Seven Sisters star cluster. Also known as the Pleiades (PLEE-uh-deez), the dipper-shaped group is more closely associated with the winter sky than the summer. In July it re-emerges during morning twilight, stalks the wee hours in August and looks down on earthlings from overhead on December evenings.

You can watch both moon and sisters with the naked eye, but binoculars will enhance the view. Next to the cluster, will the tweezers moon look closer to home than ever before? Take a look and see what you think.

Vulcan out, Styx and Kerberos win in Pluto moons name game

Kerberus and Styx join Pluto’s ever-growing family of moons. This discovery image, taken by the  Hubble Space Telescope, shows five moons orbiting the  icy dwarf planet Pluto. The darker stripe in the center is because the picture is constructed from a long exposure  to capture the faint satellites of Nix, Hydra, Kerberos and Styx, and a shorter exposure to capture brighter Pluto and Charon. Credit: NASA/ESA

The International Astronomical Union (IAU) has spoken and christened Pluto’s newest and tiniest moons Kerberos and Styx. Maybe you cast a vote in the informal Pluto moon naming contest in February and hoped that the number one choice Vulcan, home of Mr. Spock in the Star Trek TV series, deserved a chance.

Sorry to disappoint, but in a moment you’ll see why that hot world doesn’t work for a chilly planet on the solar system’s fringe. Hint, hint.

Pluto is one of five dwarf planets in the solar system. Its fellow dwarfs include the asteroids Ceres, Eris, Haumea and Makemake. Three of themare orbited by their own moons. Credit: NASA

The moons were picked up during a survey of the Pluto system with the Hubble Space Telescope in 2011 and 2012. Kerberos’ diameter is somewhere between 8 and 21 miles (13-34 km); Styx is even smaller at 6-15 miles (10-25 km). In early 2013 Mark Showalter, senior space research scientist at the SETI Institutewanted the public to be involved in the naming of the new moons, so he started a contest.

To be consistent with the names of the other Plutonian satellites, they had to be picked from classical mythology and reference the mythological underworld where souls traveled in the afterlife. Pluto’s deep, dark location has always given it underworld credentials.

Detail of Roman sculpture from 180 A.D.showing the three-headed dog Cerberus. From the Archaeological Museum in Crete. Credit: Tom Oates

None other than William Shatner himself, a.k.a. Captain Kirk from Star Trek, suggested Vulcan. The response was overwhelming with almost 500,000 votes and 30,000 write-ins. When the votes were tallied Vulcan handily took 1st place followed by Cerberus and Styx. Cerberus was changed to Kerberos, the Greek spelling of the word, to avoid confusion with the asteroid 1865 Cerberus.

Styx fit perfectly since this goddess ruled over the underworld river of the same name. Likewise Cerberus, the multi-headed dog that guarded the entrance to the underworld. But what about Vulcan? As the ancient Roman god of fire there’s no question about its mythological pedigree, but the IAU had some issues.

First, Vulcan had already been used as the name of a hypothetical planet 19th century astronomers hoped to find between the orbit of Mercury and the sun. Second, the current term ‘vulcanoids’ refers to hypothetical asteroids that orbit inside the orbit of Mercury. Finally, Vulcan simply doesn’t fit the underworld scheme.

You can’t get EVERYTHING you want. Showalter is “grateful to the IAU for giving such careful consideration” to the public’s suggestions. I’m thrilled that we can finally address all members of Pluto’s family by their first name.