2014 SPACEWEATHER PAGES JULY

STRANGE SITUATION: Near the peak of Solar Max, the sun has slipped into a state that resembles Solar Minimum. Sunspot numbers are low; the sun's X-ray and radio output are depressed; and NOAA forecasters estimate a scant 1% chance of solar flares during the next 24 hours. The quiet could be disturbed during the weekend, however, by the expected return of two old sunspots currently transiting the farside of the sun.

SOUTHERN DELTA AQUARIID METEOR SHOWER: Earth is entering a broad stream of debris from Comet 96P/Machholz, source of the annual Southern Delta Aquariid meteor shower. Forecasters expect as many as 20 meteors per hour to fly out of the constellation Aquarius on July 29-30 when the shower peaks. Already, NASA meteor cameras are detecting a smattering of fireballs--like one over New Mexico on July 25th:

Although the shower favors the southern hemisphere, it is possible to see Southern Delta Aquariids from the north, too, as the video above shows. The best time to look is during the hours between local midnight and sunrise.

Got clouds? Try listening to the Southern Delta Aquariid meteor shower on Space Weather Radio. The audio stream is playing echoes from a forward-scatter meteor radar in Roswell, New Mexico. Also, NASA will stream the shower from an observing site at the Marshall Space Flight Center in Alabama. Live video begins on July 29th at 9:30 pm EDT.

Near Miss: The Solar Superstorm of July 2012

July 23, 2014: If an asteroid big enough to knock modern civilization back to the 18th century appeared out of deep space and buzzed the Earth-Moon system, the near-miss would be instant worldwide headline news.

Two years ago, Earth experienced a close shave just as perilous, but most newspapers didn't mention it. The "impactor" was an extreme solar storm, the most powerful in as much as 150+ years.

"If it had hit, we would still be picking up the pieces," says Daniel Baker of the University of Colorado.

A ScienceCast video recounts the near-miss of a solar superstorm in July 2012. Play it

Baker, along with colleagues from NASA and other universities, published a seminal study of the storm in the December 2013 issue of the journal Space Weather. Their paper, entitled "A major solar eruptive event in July 2012," describes how a powerful coronal mass ejection (CME) tore through Earth orbit on July 23, 2012. Fortunately Earth wasn't there. Instead, the storm cloud hit the STEREO-A spacecraft.

"I have come away from our recent studies more convinced than ever that Earth and its inhabitants were incredibly fortunate that the 2012 eruption happened when it did," says Baker. "If the eruption had occurred only one week earlier, Earth would have been in the line of fire.

Extreme solar storms pose a threat to all forms of high-technology. They begin with an explosion--a "solar flare"—in the magnetic canopy of a sunspot. X-rays and extreme UV radiation reach Earth at light speed, ionizing the upper layers of our atmosphere; side-effects of this "solar EMP" include radio blackouts and GPS navigation errors. Minutes to hours later, the energetic particles arrive. Moving only slightly slower than light itself, electrons and protons accelerated by the blast can electrify satellites and damage their electronics. Then come the CMEs, billion-ton clouds of magnetized plasma that take a day or more to cross the Sun-Earth divide. Analysts believe that a direct hit by an extreme CME such as the one that missed Earth in July 2012 could cause widespread power blackouts, disabling everything that plugs into a wall socket. Most people wouldn't even be able to flush their toilet because urban water supplies largely rely on electric pumps.

Before July 2012, when researchers talked about extreme solar storms their touchstone was the iconic Carrington Event of Sept. 1859, named after English astronomer Richard Carrington who actually saw the instigating flare with his own eyes. In the days that followed his observation, a series of powerful CMEs hit Earth head-on with a potency not felt before or since. Intense geomagnetic storms ignited Northern Lights as far south as Cuba and caused global telegraph lines to spark, setting fire to some telegraph offices and thus disabling the 'Victorian Internet."

A report by the National Academy of Sciences details the consequences of extreme solar storms. More

A similar storm today could have a catastrophic effect. According to a study by the National Academy of Sciences, the total economic impact could exceed $2 trillion or 20 times greater than the costs of a Hurricane Katrina. Multi-ton transformers damaged by such a storm might take years to repair.

"In my view the July 2012 storm was in all respects at least as strong as the 1859 Carrington event," says Baker. "The only difference is, it missed."

In February 2014, physicist Pete Riley of Predictive Science Inc. published a paper in Space Weather entitled "On the probability of occurrence of extreme space weather events." In it, he analyzed records of solar storms going back 50+ years. By extrapolating the frequency of ordinary storms to the extreme, he calculated the odds that a Carrington-class storm would hit Earth in the next ten years.

The answer: 12%.

"Initially, I was quite surprised that the odds were so high, but the statistics appear to be correct," says Riley. "It is a sobering figure."

In his study, Riley looked carefully at a parameter called Dst, short for "disturbance – storm time." This is a number calculated from magnetometer readings around the equator. Essentially, it measures how hard Earth's magnetic field shakes when a CME hits. The more negative Dst becomes, the worse the storm. Ordinary geomagnetic storms, which produce Northern Lights around the Arctic Circle, but otherwise do no harm, register Dst=-50 nT (nanoTesla). The worst geomagnetic storm of the Space Age, which knocked out power across Quebec in March 1989, registered Dst=-600 nT. Modern estimates of Dst for the Carrington Event itself range from -800 nT to a staggering -1750 nT.

In their Dec. 2013 paper, Baker et al. estimated Dst for the July 2012 storm. "If that CME had hit Earth, the resulting geomagnetic storm would have registered a Dst of -1200, comparable to the Carrington Event and twice as bad as the March 1989 Quebec blackout."

The reason researchers know so much about the July 2012 storm is because, out of all the spacecraft in the solar system it could have hit, it did hit a solar observatory. STEREO-A is almost ideally equipped to measure the parameters of such an event.

"The rich data set obtained by STEREO far exceeded the relatively meagre observations that Carrington was able to make in the 19th century," notes Riley. "Thanks to STEREO-A we know a lot of about the magnetic structure of the CME, the kind of shock waves and energetic particles it produced, and perhaps most importantly of all, the number of CMEs that preceded it."

It turns out that the active region responsible for producing the July 2012 storm didn't launch just one CME into space, but many. Some of those CMEs "plowed the road" for the superstorm.

A paperin the March 2014 edition of Nature Communications by UC Berkeley space physicist Janet G. Luhmann and former postdoc Ying D. Liu describes the process: The July 23rd CME was actually twoCMEs separated by only 10 to 15 minutes. This double-CME traveled through a region of space that had been cleared out by yet another CME four days earlier. As a result, the storm clouds were not decelerated as much as usual by their transit through the interplanetary medium.

"It's likely that the Carrington event was also associated with multiple eruptions, and this may turn out to be a key requirement for extreme events," notes Riley. "In fact, it seems that extreme events may require an ideal combination of a number of key features to produce the 'perfect solar storm.'"

"Pre-conditioning by multiple CMEs appears to be very important," agrees Baker.

A common question about this event is, how did the STEREO-A probe survive? After all, Carrington-class storms are supposed to be mortally dangerous to spacecraft and satellites. Yet STEREO-A not only rode out the storm, but also continued taking high-quality data throughout.

"Spacecraft such as the STEREO twins and the Solar and Heliospheric Observatory (a joint ESA/NASA mission) were designed to operate in the environment outside the Earth's magnetosphere, and that includes even quite intense, CME-related shocks," says Joe Gurman, the STEREO project scientist at the Goddard Space Flight Center. "To my knowledge, nothing serious happened to the spacecraft."

The story might have been different, he says, if STEREO-A were orbiting Earth instead of traveling through interplanetary space.

"Inside Earth's magnetosphere, strong electric currents can be generated by a CME strike," he explains. "Out in interplanetary space, however, the ambient magnetic field is much weaker and so those dangerous currents are missing." In short, STEREO-A was in a good place to ride out the storm.

"Without the kind of coverage afforded by the STEREO mission, we as a society might have been blissfully ignorant of this remarkable solar storm," notes Baker. "How many others of this scale have just happened to miss Earth and our space detection systems? This is a pressing question that needs answers."

If Riley's work holds true, there is a 12% chance we will learn a lot more about extreme solar storms in the next 10 years—when one actually strikes Earth.

RADIO BURSTS FROM JUPITER: This week, Jupiter is passing behind the sun. Normally solar interference would make it difficult for radio astronomers to pick up Jupiter's shortwave radio bursts. Because the sun is so quiet, however, Jupiter is still able to maake itself heard. "I was able to capture distinct narrow-band radio emissions from Jupiter on July 21st," reports Thomas Ashcraft of New Mexico. They are the sloping lines in this dynamic spectrum he recorded using a RadioJove Project dual dipole antenna:

"At the time Jupiter was 6.3 Astronomical Units (585,621,586 miles) distant from Earth," he adds. "I think this is a neat observation because it means there is always the possibility of receiving Jupiter radio emissions here on Earth--even when the sun is in the way and Jupiter is very distant."

Jupiter's radio storms are caused by natural radio lasers in the planet's magnetosphere that sweep past Earth as Jupiter rotates. Electrical currents flowing between Jupiter's upper atmosphere and the volcanic moon Io can boost these emissions to power levels easily detected by ham radio antennas on Earth. Jovian "S-bursts" and "L-bursts" mimic the sounds of woodpeckers, whales, and waves crashing on the beach. Here are a few audio samples: S-bursts, S-bursts (slowed down 128:1), L-Bursts. The type of emissions Ashcraft picked up on July 21st were S-bursts.

MIDNIGHT SUNDOGS: Some of us have seen the midnight sun. Even more have witnessed sundogs. But have many people have seen a mashup of the two--the elusive midnight sundog? On July 21-22, Stine Bratteberg photographed the combo from Bleik, Andøya, Norway:

"These fantastic sundogs appeared near midnight on the last day of the summer Midnight Sun here in northern Norway," says Bratteberg.

Sundogs, the rainbow-colored splashes of light on either side of the sun, are caused by sunlight striking ice crystals in the air. Plate-shaped crystals flutter down from the sky like leaves falling from trees. Aerodynamic forces align their flat sides parallel to the ground, and when sunlight hits a patch of well-aligned crystals at the right distance from the sun, voila!--a sundog. Bratteberg's photo also captured a faint midnight sun halo and a midnight upper tangent arc.

You can see a lot of midnight atmospheric optics from the Arctic Circle. But not for much longer. As northern summer comes to an end, the midnight sun will fade and auroras will chase the sundogs into the darkening Arctic night. Monitor the realtime aurora gallery for updates.

QUIET SUN: Solar activity remains very low. There is only one sunspot (AR2119) on the Earth-facing side of the sun, and it has a simple magnetic field that poses no threat for strong explosions. NOAA forecasters estimate a scant 1% chance of M- orX-flares during the next 24 hours

NOCTILUCENT CLOUDS: Last night, a bank of noctilucent clouds (NLCs) rippled across northern Europe. "They were stunning," reports Alex Lebedev, who witnessed the apparition from Kohtla-Järve, Ida-Virumaa, Estonia. The display was so wide, it doesn't fit in the space provided below; click to view the complete panorama:

NLCs are Earth's highest clouds. Seeded by "meteor smoke," they form at the edge of space 83 km above Earth's surface. When sunlight hits the tiny ice crystals that form around the meteor debris, the clouds glow electric blue.

July is the best month to see NLCs. They favor the climate of summer because that is when water molecules, warmed by summer sunlight, are wafted up from the lower atmosphere to mix with the meteor smoke. That is also, ironically, when the upper atmosphere is coldest, allowing the ice crystals of NLCs to form.

The natural habitat of noctilucent clouds is the Arctic Circle. In recent years, however, they have spread to lower latitudes with sightings as far south as Utah and Colorado. This will likely happen in 2014 as well. Observing tips: Look west 30 to 60 minutes after sunset when the Sun has dipped 6^o to 16^o below the horizon. If you see blue-white tendrils zig-zagging across the sky, you may have spotted a noctilucent cloud.

THE ALL QUIET EVENT: The "All Quiet Event" is still underway. For the 6th day in a row, solar activity is extremely low, with weak solar wind, no flares, and a sunspot number near zero. NOAA forecasters put the odds of a significant flare today at no more than 1%

ED SPRITES OVER NEW MEXICO: Solar activity is extremely low. Nevertheless, space weather continues. High above thunderstorms in the American west, red sprites are dancing across the cloudtops, reaching up to the edge of space itself. Harald Edens photographed this specimen on July 18th from the Langmuir Laboratory for Atmospheric Research in New Mexico:

"This colorful sprite occurred over a large thunderstorm system in northeast New Mexico and was visible to the naked eye," says Edens. "I took the picture using a Nikon D4s and a 50 mm f/2 lens at ISO 25600."

Inhabiting the upper reaches of Earth's atmosphere alongside noctilucent clouds, meteors, and some auroras, sprites are a true space weather phenomenon. Some researchers believe they are linked to cosmic rays: subatomic particles from deep space striking the top of Earth's atmosphere produce secondary electrons that, in turn, could provide the spark that triggers sprites.

Although sprites have been seen for at least a century, most scientists did not believe they existed until after 1989 when sprites were photographed by cameras onboard the space shuttle. Now "sprite chasers" regularly photograph the upward bolts from their own homes. Give it a try!

THIS BLAST APPEARS TO HIT JUPITER, BUT IT DOESNT AS JUPITER IS ACTUALLY 500 MILLION MILES BEHIND THE SUN

mages taken by NASA's STEREO-B probe, which is stationed over the farside of the sun, suggest that the CME was propelled into space by an erupting filament of magnetism possibly connected to a small sunspot. We will get a direct view of the blast site in a few days when it rotates onto the Earthside of the sun. Overall, solar activity remains low despite this relatively minor outburst.

The small sunspots barely visible today are not about to break the quiet. None of them has the kind of complex magnetic field that harbors energy for strong flares. NOAA forecasters estimate the odds of a significant flare (M- or X-class) in the next 24 hours to be no more than 1%.

Before July 17, 2014, the previous spotless day was August 14, 2011, a gap of nearly 3 years. What happened then provides context for what is happening now. Overall, 2011 was a year of relatively high solar activity with multiple X-flares; the spotless sun was just a temporary intermission. 2014 will probably be remembered the same way. Or not. Almost anything is possible because, as one pundit observes, "you just can't predict the sun."

ROSETTA COMET IS A CONTACT BINARY: The European Space Agency's Rosetta probe is approaching Comet 67P/Churyumov-Gerasimenko for a historic mission to orbit and land on the comet's nucleus. As Rosetta approaches the comet (now less than 10,000 km away), the form of the nucleus is coming into focus. And it is strange:

Some observers have noted the comet's resemblance to a rubber duck. The technical term is "contact binary." One elongated object appears stuck to a smaller bulbous piece. No one knows how the comet came to be this way. It could be the result of a slow-motion "sticky collision" between two objects, an odd-shaped fragment of a catastrophic impact, or something else entirely. One thing is sure: This could present some interesting challenges for Philae, the probe's lander, which is slated to touch down on the comet's surface in early November.

Many questions will be answered by August 6th when Rosetta reaches 67P and goes into orbit. Stay tuned!

SUNSPOT NUMBER DROPS TO ZERO: Solar activity is very low. July 17th brought the first spotless day in nearly three years. The face of the sun was completely blank and the sunspot number dropped to zero. Now, however, two small sunspots are emerging, circled in this image from NASA's Solar Dynamics Observatory:

Neither of these small spots has the kind of complex magnetic field that harbors energy for strong flares. The quiet is therefore expected to continue through the weekend. NOAA forecasters estimate the odds of an M-flare in the next 3 days to be no more than 1%.

Before July 17, 2014, the previous spotless day was August 14, 2011, a gap of nearly 3 years. What happened then provides context for what is happening today. Overall, 2011 was a year of relatively high solar activity with multiple X-flares; the spotless sun was just a temporary intermission. 2014 will probably be remembered the same way. As new sunspots emerge and grow, the Solar Max of 2014 will pick up where it left off a couple weeks ago when sunspots were abundant. However, because no one can predict the solar cycle, this "All Quiet Event" is worth monitoring.

THREE WEEKS TO COMET 67P: The European Space Agency's Rosetta probe is now less than 10,000 km from its target: 67P/Churyumov-Gerasimenko. Rosetta is expected to reach and begin orbiting the comet's nucleus on August 6th. Long-range images suggest that the comet is a contact binary. This could present some interesting challenges for Philae, the probe's lander, which is slated to touch down on the comet's surface in early November. Check the Rosetta home page for updates.

July 14, 2014: In July 2015, NASA will discover a new world. No one knows what to expect when the alien landscape comes into focus. There could be icy geysers, towering mountains, deep valleys, even planetary rings.

On July 14^th, 2015, NASA's New Horizons spacecraft will make a close flyby of that distant world. "Because Pluto has never been visited up-close by a spacecraft from Earth, everything we see will be a first," says Adriana Ocampo, the Program Executive for NASA's New Frontiers program at NASA headquarters. "I know this will be an astonishing experience full of history making moments."

A new ScienceCast video previews what New Horizons might see when it reaches Pluto in July 2015.Play it

The mission's principal investigator, Alan Stern of the Southwest Research Institute, has likened the way New Horizons will revolutionize knowledge about the Pluto system to the way that Mariner 4, which flew past Mars in July 1965, revolutionized knowledge of that planet. At the time, many people on Earth thought the Red Planet was a lush world with water and vegetation friendly to life. Instead, Mariner 4 revealed a desert world of haunting beauty.

New Horizons’ flyby of Pluto will occur almost exactly 50 years after Mariner 4’s flyby of Mars—and it could shock observers just as much.

Pluto is almost completely unknown. It is so far away, that even the Hubble Space Telescope strains to see it. The best images so far show little more than Pluto's shape (spherical) and color (reddish). Over the years, changes in those color patterns hint at a dynamic planet where something is happening, but no one knows what.

By late April 2015, New Horizons will be close enough to Pluto to take pictures rivaling those of Hubble—and it only gets better from there. At closest approach in July 2015, New Horizons will be a scant 10,000 km above the surface of Pluto. If New Horizons flew over Earth at the same altitude, it could see individual buildings and their shapes.

Flying so close to Pluto could be risky business. Pluto has five known moons: Charon, Styx, Nix, Kerberos, and Hydra. Numerical simulations show that meteoroids striking those satellites could send debris into orbit around Pluto, forming a debris system that waxes and wanes over time in response to changes in the bombardment. During the approach to Pluto, the science team will keep a wary eye out for debris, and guide the spacecraft away from danger.

"The New Horizons Team continues to do a magnificent job in keeping the spacecraft healthy and ready for this incredible rendezvous," Ocampo says. "The spacecraft is in good hands."

No one knows what New Horizons will discover. "Many predictions have being made by the science community, including possible rings, geyser eruptions, and even lakes," says Ocampo. "Whatever we find, I believe Pluto and its satellites will surpass all our expectations and surprise us beyond our imagination."

"Think about seeing something for the first time and discovering the unknown," she concludes. "That’s what we're about to do."

GROWING QUIET: The odds of an Earth-directed solar flare are plummeting as sunspots AR2108 and AR2109 rotate over over the sun's western limb. The departure of these two active regions leaves the face of the sun almost blank. Solar activity should remain low for the next 24-48 hours.

FLY ME TO THE SUPERMOON: The Moon's orbit around Earth is not a circle, it's an ellipse. When a full Moon occurs on the near side of the orbit, it looks extra big and bright, and we call it a "supermoon." The first of three supermoons arrived on July 12th:

"This weekend I was on my deck taking some zoom photos of the supermoon when an airplane flew by," says photographer Ralfo Winter. "It was coming in for a landing at New York City."

As explained in a video from Science@NASA, the technical term for this phenomenon is "perigee Moon." A nearby perigee Moon can be 14% bigger and 30% brighter than other full Moons of the year. This kind of Moon is not particularly rare; they come along every 13 months or so. However, this summer we will have threesupermoons in a row. The next one is August 12th.

NOCTILUCENT CLOUDS: The weekend of July 12-13 brought another outbreak of noctilucent clouds (NLCs) to Europe. Across the northern reaches of the continent, skies were criss-crossed by signature ripples of electric blue, like these photographed by Jaan Jalgratas of Tartu, Estonia:

"The display was very bright and it extended at least 35 degrees above the horizon," says Jalgratas. "It was my best sighting ever."

NLCs are Earth's highest clouds. Seeded by "meteor smoke," they form at the edge of space 83 km above Earth's surface. When sunlight hits the tiny ice crystals that make up these clouds, they glow electric blue.

In the northern hemisphere, July is the best month to see them. NLCs appear during summer because that is when water molecules are wafted up from the lower atmosphere to mix with the meteor smoke. That is also, ironically, when the upper atmosphere is coldest, allowing the ice crystals of NLCs to form.

THREE SUPERMOONS IN A ROW: Today's full Moon is a perigee "supermoon," as much as 14% closer and 30% brighter than other full moons of the year. John Stetson photographed the swollen orb setting this morning just minutes after sunrise:

INCOMING CME, GLANCING BLOW POSSIBLE: Earth could receive a glancing blow from a CME on July 13th. It comes from a magnetic filament that erupted from the sun's northern hemisphere on July 9th and hurled part of itself into space. Minor geomagnetic storms are possible when the CME arrives.

DEPARTING SUNSPOTS: The threat of an Earth-directed flare is subsiding as sunspots AR2108 and AR2109 rotate off the solar disk. Maximilian Teodorescu of Magurele (Ilfov), Romania, took this picture of the departing behemoths on July 13th:

Although the sunspots are no longer facing Earth, and will soon disappear altogether, the threat of solar activity is not completely extinguished. From the sun's western limb, the solar magnetic field curves back toward Earth. If these sunspots flare as they crest the western limb, the explosion will be well connected to our planet, magnetically speaking. Charged particles would be guided in our direction, possibly causing a radiation storm around Earth.

First, however, we need a flare, and these sunspots do not seem inclined to oblige. Despite their size and potent magnetic fields, neither sunspot has produced a significant eruption in almost two weeks. The quiet is likely to continue.

HEART-SHAPED CLOUD PHENOMENON: Frequent fliers who look out the window of their planes often see the shadow of the aircraft dipping in and out of clouds below. The interplay of light and shadow with water droplets in the clouds can produce colorful rings of light called "glories." On July 13th, Tony DeFreece saw a glory that was not a colorful ring, but rather a heart:

"I was flying over Oregon when I looked out and saw this heart-shaped figure," he says. "It was one of those moments when the Universe aligns and takes your breath away."

DeFreece suspects, probably correctly, that the shape of the clouds bent the usual circular glory into the heart-shaped apparition. Mystery solved? Not entirely. Glories are caused by sunlight reflected backwards from water droplets in clouds. Exactly how backscattering produces the colorful rings, however, is a mystery involving surface waves and multiple reflections within individual droplets. Each sighting is a lovely puzzle, so grab the window seat and keep an eye on the clouds below.

QUIET WITH A CHANCE OF FLARES: Solar activity is low, but the quiet is unlikely to persist. There are three sunspots with unstable magnetic fields capable of strong eruptions: AR2108, AR2109, AR2113. NOAA forecasters estimate a 75% chance ofM-flares and 15% chance of X-flares on July 10th.

SPOTTY SUNRISE: Astrophotographers around the world are snapping pictures of this week's large sunspots. "After taking some sunspot images yesterday afternoon, I was thinking that it would be nice to capture the spotty Sun at sunrise," says Stephen Mudge of Brisbane, Australia. "And then I thought it would be even nicer if that sunrise was behind the city buildings. So after a bit of time studying Stellarium and looking at maps, and then a quick reconnaissance drive, I settled on Green Hill Reservoir as a suitable location for a photo shoot." This was the result

"I got up there just as dawn started and took some panoramas of the city. Then, with the camera still in position on the tripod, I added a Baader solar filter and captured the rising sun with exposures every 3.5 minutes," explains Mudge. "I managed to pick the location perfectly (with the Sun rising right in the middle of the city), and the weather cooperated beautifully, so I'm pretty happy with the result!"

Who knew sunspots could be a muse for creative photography? Check the realtime photo gallery for more examples.

-M-CLASS SOLAR FLARE: Forecasters expected a solar flare today, and indeed one has occurred. But it came from an unexpected source. Emerging sunspot AR2113 showed that it is capable of strong flares with an M6-class eruption at 1630 UT on July 8th. NASA's Solar Dynamics Observatory recorded the extreme ultraviolet flash:

Ionizing radiation from the flare briefly disturbed the propagation of shortwave radio transmissions on the dayside of Earth, but conditions have since returned to normal. The impulsive flare might have produced a coronal mass ejection (CME); if so, the storm cloud is almost certainly not heading toward Earth. For now, this sunspot is too far off the sun-Earth line to produce geoeffective CMEs.

With this flare, AR2113 joins two other sunspots capable of potent activity: AR2108 and AR2109. NOAA forecasters estimate a 70% chance of M-flares and a 15% chance of X-flares on July 8th.

M6-CLASS SOLAR FLARE: On July 8th, Earth-orbiting satellites detected a strong M6-class solar flare. The flare itself came as little surprise because there is a phalanx of large sunspots crossing the solar disk. However, the source of the flare was unexpected.

WAITING FOR FLARES: For days, solar activity has been low, but the quiet seems unlikely to last. Two big sunspots, AR2108 and AR2109, have unstable "beta-gamma-delta" magnetic fields that harbor energy for strong, Earth-directed eruptions. NOAA forecasters estimate a 60% chance of M-flares and a 10% chance of X-flares on July 7th

MOSTLY QUIET WITH A CHANCE OF FLARES: Solar activity is low. However, there are four sunspots facing Earth that pose a threat for geoeffective flares: AR2104, AR2107, AR2108, AR2109. NOAA forecasters estimate a 60% chance that one of those active regions will produce an M-flare during the 4th of July weekend.

MONSTER ASTEROIDS CONVERGE: The two most massive objects in the asteroid belt, dwarf planet Ceres and minor planet Vesta, are converging for a close encounter in the night sky on July 4th and 5th. Last night in Italy, Gianluca Masi used a remotely operated telescope to photograph the monster asteroids only 13 arcminutes apart--less than half the width of a full Moon. The line splitting the two is a terrestrial satellite:

At closest approach on July 5th, the two asteroids will be only 10 arcminutes apart in the constellation Virgo. They are too dim to see with the unaided eye, but easy targets for binoculars and small telescopes. Observing tips are available from Sky and Telescope.

Got clouds? You can watch the close encounter online. Choose between Gianluca Masi's Virtual Telescope Project (which begins July 5th at 4:00 p.m. EDT) or Slooh's webcast (July 3rd at 8 p.m. Eastern Daylight Time).

Quite near the two asteroids on the sky, though utterly invisible, is NASA's Dawn spacecraft. Dawn recently finished visiting Vesta and is now en route to Ceres. The ion-propelled spacecraft will enter orbit around Ceres next March. Cameras on Dawn will resolve the pinprick of light you see this weekend into a full-fledged world of unknown wonders. Stay tuned for that!

CHANCE OF FLARES: NOAA forecasters estimate a 50% chance of M-class solar flares today. The likely source would be big sunspot AR2104, which has a 'beta-gamma-delta' magnetic field that harbors energy for strong eruptions

MORE SUNSPOTS: The sunspot number, already high, ticked upward again today with the arrival of another large active region over the sun's eastern limb. --and keep an eye on "AR2109":

The explosive potential of this new sunspot is unknown. It will come into sharper focus later today and tomorrow as the region turns more directly toward Earth, revealing whether or not AR2109 has the kind of unstable magnetic field that leads to strong flares. For now, solar activty remains low despite the increasing sunspot count.

CARBON OBSERVATORY LAUNCHED: Yesterday morning at 2:56 AM PDT, NASA's Orbiting Carbon Observatory-2 (OCO-2) blasted into space from the Vandenberg AFB in California. After liftoff, the exhaust from the satellite's Delta II rocket glowed so brightly that Juan Perez was able to see it 500 miles away in Wittmann, Arizona:

Now orbiting Earth, OCO-2 is set to begin a two-plus year mission to locate the sources and sinks of atmospheric carbon dioxide, the leading human-produced greenhouse gas responsible for global warming. The launch was from the west coast so the spacecraft could enter a polar orbit of the Earth, a flight path that will see it cross over the Arctic and Antarctic regions during each revolution and get a complete picture of the Earth. It will fly about 438 miles above the planet's surface to take its readings. While ground stations have been monitoring carbon dioxide concentrations for years, OCO-2 will be the first spacecraft to conduct a global-scale reading over several seasons. For more views of the launch, browse the realtime photo gallery:

ELECTRIC-BLUE SUNRISE: For people in the northern hemisphere, July is the best time of the year to see noctilucent clouds (NLCs). The month got off to a good start on July 1st when the sunrise over Radebeul, Germany turned electric-blue:

"This morning was extremely electric blue over Saxony," says photograher Heiko Ulbricht. "What a great display of noctilucent clouds! I spent much of the night watching the World Cup with friends. At about 2 o'clock in the morning, we drove to a field in Radebeul near the Astronomical Observatory. When the sun came up we were rewarded--a great morning! "

NLCs appear during summer because that is when water molecules are wafted up from the lower atmosphere to mix with the meteor smoke. That is also, ironically, when the upper atmosphere is coldest, allowing the ice crystals of NLCs to form.

The natural habitat of noctilucent clouds is the Arctic Circle. In recent years, however, they have spread to lower latitudes with sightings as far south as Utah and Colorado. This will likely happen in 2014 as well. Observing tips: Look west 30 to 60 minutes after sunset when the Sun has dipped 6^o to 16^o below the horizon. If you see luminous blue-white tendrils spreading across the sky, you may have spotted a noctilucent cloud.

BROODING GIANT: Big sunspot AR2104, which emerged over the weekend, has developed a 'beta-gamma-delta' magnetic field that harbors energy for X-class solar flares. So far, however, the sunspot has been relatively quiet, producing no more than a few minor C-flares. Sergio Castillo photographed the brooding giant on June 30th from his backyard observatory in Inglewood, CA:

Castillo used a solar telescope capped with a "Calcium-K" filter tuned to 3933 Å, a wavelength that reveals the bright magnetic froth around active sunspots. "The magnetic froth is amazingly visible around AR2104," says Castillo. "I truly hope this active region brings fireworks just in time for the 4th of July."

He might get his wish. NOAA forecasters estimate a growing 40% chance of M-class flares and a 5% chance of X-flares during the next 24 hours. The odds of geoeffective eruptions will increase even more in the days ahead as the sunspot turns toward Earth.

Recent & Upcoming Earth-asteroid encounters:

Asteroid	Date(UT)	Miss Distance	Size
2014 MG6	Jun 27	9.5 LD	26 m
2014 MV18	Jun 30	7.2 LD	80 m
2014 MJ26	Jul 2	9.7 LD	47 m
2013 AG69	Jul 8	2.7 LD	15 m
2014 MF6	Jul 9	9.1 LD	310 m
2011 PU1	Jul 17	7.9 LD	43 m
2002 JN97	Aug 2	61.4 LD	2.0 km
2001 RZ11	Aug 17	34.2 LD	2.2 km
2013 WT67	Aug 17	16.1 LD	1.1 km