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NIGHT-SHINING CLOUDS REAPPEAR OVER ANTARCTICA: The southern season for noctilucent clouds (NLCs) is underway. NASA's AIM spacecraft detected the first wispy tendrils of NLCs over Antarctica on Nov. 21st and since then the electric-blue clouds have spread and brightened. Scroll down the page and look left for latest images.
COMET MOVIE--UPDATED: Comet ISON is getting all the press, but there is a second comet near the sun as well: Comet Encke. NASA's STEREO-A spacecraft is monitoring both. Click to view an updated movie of the solar wind buffeting two comets:
In the movie, which spans a three+ day period from Nov. 20 to Nov. 23, the sun is to the right, off-screen. At first glance, Earth and Mercury appear to be labeled backwards. The strange arrangement is actually correct. This is how the two planets appear from STEREO-A's vantage point over the farside of the sun.
"The dark 'clouds' moving from left to right are density enhancements in the solar wind, and these are what are causing the ripples you see in the comet tails," explains Karl Battams of NASA's Comet ISON Observing Campaign.
The ripples could become even more dramatic if a CME hits the comets. This is Comet ISON's first visit to the sun, but Comet Encke has been here before. In 2007 a CME hit Encke and ripped off its tail. Battams and other researchers hope something similar is about to happen now. "I'd love to see a big CME hit Comet ISON," he says in a story from Science@NASA. Watching the impact could teach researchers new things about CMEs and comets.
Stay tuned for updated movies from NASA's solar fleet.
Realtime Comet ISON Photo Gallery
WHICH SIDE OF THE SUN IS FACING COMET ISON? When Comet ISON sweeps through the sun's atmosphere on Nov. 28th, it will be in the 'hot zone' for CMEs. A strike by one of the massive storm clouds probably wouldn't destroy the comet, but it could have a dramatic effect on the comet's fragile tail. The odds of a strike depend on which side of the sun is facing the comet at the time of the flyby. This is something you can monitor using a NASA iPhone app called the Interplanetary 3D Sun:
The app displays an interactive 3D model of the entire sun photographed by extreme UV cameras onboard NASA's twin STEREO probes. The data are realtime and fully interactive (pinch, spin and zoom). As shown in this target list, you can view the sun from many locations around the solar system--including Comet ISON.
Active regions are color-coded by their potential for flares: Orange means "expect M-class solar flares," while red denotes sunspots capable of X-flares. In the screen shot above we see that Comet ISON is bearing down on an active region, AR1904, that poses a threat for M-class eruptions. A CME might be in the offing after all. Solar flare alerts: text, voice
COMET ISON, PARTING SHOTS: As Comet ISON approaches the sun, it is becoming increasingly difficult for observers on Earth to photograph the comet. Indeed, by Nov. 24th it seemed impossible. But it only seemed that way. Working from a high-altitude site in the Canary islands, Juan Carlos Casado successfully imaged Comet ISON on Sunday morning deep inside the rosy glow of dawn:
"I took this picture of Comet ISON on Nov. 24th at 6: 25 UT from the Teide Observatory," says Casado. "The comet was over the distant island of Gran Canaria above a sea of clouds about 1 hour before sunrise and only 16° from the sun. The exceptional atmospheric conditions of Teide Observatory allowed me to capture the image."
Could this be the last clear photo of Comet ISON taken from Earth? No one knows. Stay tuned to the realtime photo gallery for more parting shots:
Realtime Comet ISON Photo Gallery
Realtime Space Weather 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 Nov. 25, 2013, the network reported 11 fireballs.
(9 sporadics, 1 Leonid, 1 November omega Orionid)
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 November 25, 2013 there were 1439 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 |