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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PHONESAT LAUNCHED: A satellite controlled by a smartphone? Believe it. Last night, Nov. 19th, NASA launched PhoneSat 2.4 into Earth orbit. The innovative device rode to space onboard a Minataur rocket from the Wallops Flight Facility in Virginia. Ten student-built CubeSats were onboard, too. The launch was widely visible along the US eastern seaboard: photos.
COMET ISON PLUNGES TOWARD THE SUN: Comet ISON is plunging toward the sun at 140,000 mph (62 km/s). You can almost feel the velocity in this image taken on the morning of Nov. 20th by astronomers using the 0.4 meter telescope at the Observatorio de la Hita in La Puebla de Almoradiel, Toledo, Spain:
"The comet looked very bright," report the observing team. "The tail was not as well defined today because of the proximity of morning twilight...but still splendid!!"
The comet is brightening rapidly as it approaches the sun. Experienced observers put ISON's rising magnitude near +4.0, well above the threshold of naked-eye visibility. The problem is, the glare of the sun is brightening even faster. Amateur photography of the comet will be possible for a few more days and, soon, only NASA's fleet of solar observatories will be able to track the sundiver.
Observationally speaking, the next big event in the timeline of Comet ISON's journey comes on Nov. 21st when the comet enters the field of view of NASA's STEREO-A spacecraft. The Heliospheric Imager on STEREO-A will pick up the comet just as Earth-bound telescopes begin to lose it. In the days that follow, STEREO-B, SOHO and the Solar Dynamics Observatory will join the hunt, providing continuous views of Comet ISON all the way to perihelion (closest approach to the sun) on Nov. 28th. Stay tuned!
Realtime Comet ISON Photo Gallery
Ephemerides: Comet ISON, Comet Lovejoy, Comet Encke, Comet LINEAR X
X-CLASS SOLAR FLARE (UPDATED): Departing sunspot AR1893 (not AR1897 as previously reported) erupted on Nov. 19th, producing an X1-class solar flare. NASA's Solar Dynamics Observatory recorded the explosion's extreme ultraviolet flash at 10:26 UT:
Although the sunspot is not directly facing Earth, the flare did affect our planet. Mainly, the UV flash produced a wave of ionization in the upper atmosphere over Europe, Africa and parts of Asia. A brief blackout of HF radio transmissions around the poles might have also occurred. UPDATE: The explosion hurled a CME into space: movie. But the cloud is not heading toward Earth. Solar flare alerts: text, voice
Realtime Space Weather Photo Gallery
Realtime Aurora Photo Gallery
Realtime Comet ISON 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. 20, 2013, the network reported 47 fireballs.
(27 sporadics, 17 Leonids, 2 Northern Taurids, 1 Alpha Monocerotid)
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 20, 2013 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 |