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TROUBLE FOR THE STEREO MISSION: NASA's twin STEREO probes, which can see the farside of the sun and make 3D models of incoming CMEs, have revolutionized space weather forecasting. We might have to do without them for a while. Later this year, the twin probes will pass directly behind the sun. Originally, mission planners expected a brief eclipse. Instead, operations will be curtailed for more than a year. The reason has to do with STEREO's high gain antenna feed. Ironically, when the antenna points too close to the sun, it overheats. As the probes pass behind the sun, they can't point their antennas at Earth without heat-sensitive components becoming dangerously hot. This engineering problem was not anticipated when STEREO was launched in 2006. On the bright side, it might be possible to avert a complete blackout using the antenna's sidelobes. Update: Tests in August will evaluate the possibility that low-bandwidth science data may be transmitted for a couple of hours each day. Stay tuned for updates. Solar flare alerts: text, voice
SPEAKING OF THE FARSIDE.... During the early hours of June 27th, a series of bright CMEs billowed over the sun's northern limb. The Solar and Heliospheric Observatory (SOHO) recorded the blasts:
NASA's STEREO probes saw the eruptions that gave birth to these clouds; the blast sites were on the farside of the sun. During STEREO's year-long brownout, pinpointing farside eruptons won't always be possible. Data trickling out of the STEREO's antenna's sidelobes simply cannot provide the kind of uninterrupted coverage required to catch every flare.
The situation could worsen if, during STEREO's absense, something happens to SOHO. Launched in 1995, the Solar and Heliospheric Observatory is an old spacecraft operating far beyond its design lifetime. A mishap for SOHO could leave us without any operating space-based coronagraphs until STEREO comes back online in late 2015. Such a scenario would make it impossible to detect and track emerging CMEs. Imagine a whole year of space weather forecasting based on supposition and guesswork! This possibility highlights the need for a next generation of spacecraft to monitor the sun. Solar flare alerts: text, voice
GIGANTIC SPRITES OVER THE USA: With the arrival of summer, thunderstorm activity is underway across the USA. We all know what comes out of the bottom of thunderstorms: lightning. Lesser known is what comes out of the top: sprites. "Lately there has been a bumper crop of sprites," reports Thomas Ashcraft, a longtime observer of the phenomenon. "Here is one of the largest' 'jellyfish' sprites I have captured in the last four years." The cluster shot up from western Oklahoma on June 23, so large that it was visible from Ashcraft's observatory in New Mexico 289 miles away:
"According to my measurements, it was 40 miles tall and 46 miles wide. This sprite would dwarf Mt. Everest!" he exclaims.
Also in New Mexico, Jan Curtis saw a cluster of red sprites just one night later, June 24. "I've always wanted to capture these elusive atmospheric phenomena and last night I was finally successful."
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.
Ashcraft explains how he does it: "My method for photographing sprites is fairly simple. First I check for strong thunderstorms within 500 miles using regional radar maps accessible on the Internet. There must be a locally clear sky to image above the distant storm clouds. Then I aim my cameras out over the direction of the thunderstorms (which will be hot red or purple on the radar maps) and shoot continuous DSLR exposures. I usually shoot continuous 2 second exposures but if there is no moon then I will shoot up to 4 second exposures. Then I run through all the photographs and if I am lucky some sprites will be there. It might take hundreds to usually thousands of exposures so be prepared for many shutter clicks. I use a modified near infrared DLSR but any DLSR will capture sprites. Note that it does require persistence and a little bit of luck."
Inhabiting the upper reaches of Earth's atmosphere alongside meteors, noctilucent clouds and some auroras, sprites are a true space weather phenomenon. Now is a good time to see them.
Realtime Space Weather Photo Gallery
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Realtime NLC Photo Gallery
Realtime Aurora 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 Jun. 27, 2014, the network reported 8 fireballs.
( 8 sporadics)
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 June 27, 2014 there were 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 |