When is the best time to see auroras? Where is the best place to go? And how do you photograph them? These questions and more are answered in a new book, Northern Lights - a Guide, by Pal Brekke & Fredrik Broms.
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EARTH-DIRECTED ERUPTION: A magnetic filament snaking down the middle of the solar disk erupted on Aug. 15th at approximately 1700 UT. Quick-look data from NASA's STEREO probes suggest that the blast hurled a CME toward Earth. If so, the cloud would probably arrive on or about Aug. 18th. Stay tuned for updates.
THE LANDSCAPE OF A COMET: On August 6th, Europe's Rosetta spacecraft rendezvoused with Comet 67P/Churyumov-Gerasimenko and began to fly alongside it. Seven days later, mission scientists released this spectacular view of the comet's double-lobed core:
A closer look reveals many interesting features: While the comet's head (in the top half of the image) is scored with parallel linear features, the neck is peppered with boulders resting on a smooth underlying terrain. In comparison, the comet's body (lower half of the image) is jagged and dimpled by crater-like depressions.
Now imagine this magnificent landscape ruptured by dozens of geysers spewing dust and gas into space. Future pictures may show exactly that. Rosetta will follow this comet for more than a year as it approaches the sun. In 2015, if not sooner, solar heating will activate the comet's icy core, creating a riot of activity the likes of which no spacecraft has ever seen before. Stay tuned for that.
Realtime Comet Photo Gallery
PERSEID METEOR UPDATE: Earth is now exiting the debris stream of Comet Swift-Tuttle, bringing an end to the Perseid meteor shower. According to the International Meteor Organization, the shower peaked on August 13th with as many as 70 meteors/hr (ZHR). As the shower subsides, you can continue to hear late-arriving Perseid radar echoes on Space Weather Radio.
Before the Perseid meteor shower began, forecasters worried that people might not see it due to the glare of a supermoon. This photo illustrates why the Perseids succeeded in spite of lunar interference; the shower is rich in fireballs:
"This was the brightest Perseid I saw on the night of August 12/13," says photographer Pete Lawrence. "Visually, it was a stunner!"
After the meteor exploded over Lawrence's home in Selsey, UK, a wispy trail of debris appeared where the meteor had been a split-second before. "I recorded it in the very next frame," he says.
This is "meteor smoke," a sinuous cloud of microscopic cinders tracing the path of the incinerating fireball. The particles of meteor smoke disperse in Earth's upper atmosphere and, ultimately, become the seeds of noctilucent clouds. All meteors produce such smoke, but only the brightest fireballs create a lingering trail bright enough to see with the unaided eye.
Light from the supermoon, ironically, helps us see meteor smoke, because reflected moonlight increases the visibility of smoky debris. As a result, the smoke may have been photographed more often than usual during the 2014 Perseids. Browse the realtime meteor gallery to search for additional examples.
Realtime Meteor Photo Gallery
CONVERGING PLANETS: Venus and Jupiter are converging for a stunning conjunction in the pre-dawn sky. At closest approach on August 18th, the two planets will be just 0.2 degrees apart, tight enough to hide behind the tip of your outstretched pinky. Flying astrophotographer, pilot Brian Whittaker, photographed the converging pair 35,000 feet over Northern Ontario, Canada, on August 12th:
"I spotted Jupiter with Venus just 6 days before the super conjunction," says Whittaker. "It was a beautiful view--and it's only going to get better."
Observing tips: Look east about 30 minutes before sunrise. A clear view of the horizon is required to see the low-hanging pair. Each morning between now and the 18th the distance between the two will decrease as they converge for their dramatic meeting next Monday.
No special optics are required to see the amazingly bright pair, but if you have binoculars, use them. A quick scan of the sky around Venus and Jupiter on August 18th reveals that the two worlds are not alone. The planets are converging right beside M44, the Beehive Cluster. Located about 500 light years from Earth, this busy cluster of stars is barely visible to the naked eye, but it is an easy target for ordinary binoculars. At first glance it might seem that a pair of supernovas has gone off inside the cluster—but that's just Venus and Jupiter passing by.
Photographers, if you take pictures of the morning show, submit them here.
Realtime Space Weather Photo Gallery
Realtime Aurora Photo Gallery
Realtime NLC Photo Gallery
Every night, a network of NASA all-sky cameras scans the skies above the United States for meteoritic fireballs. Automated software maintained by NASA's Meteoroid Environment Office calculates their orbits, velocity, penetration depth in Earth's atmosphere and many other characteristics. Daily results are presented here on Spaceweather.com.
On Aug. 15, 2014, the network reported 57 fireballs.
(33 Perseids, 21 sporadics, 3 kappa Cygnids)
In this diagram of the inner solar system, all of the fireball orbits intersect at a single point--Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies]
Potentially Hazardous Asteroids (PHAs
) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones
all the time.
On August 15, 2014 there were 1492 potentially hazardous asteroids. Notes: LD means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the Moon. 1 LD also equals 0.00256 AU. MAG is the visual magnitude of the asteroid on the date of closest approach.
| ||The official U.S. government space weather bureau |
| ||The first place to look for information about sundogs, pillars, rainbows and related phenomena. |
| ||Researchers call it a "Hubble for the sun." SDO is the most advanced solar observatory ever. |
| ||3D views of the sun from NASA's Solar and Terrestrial Relations Observatory |
| ||Realtime and archival images of the Sun from SOHO. |
| ||from the NOAA Space Environment Center |
| ||the underlying science of space weather |