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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INCOMING CMEs: For the next three days, a series of CMEs will sweep past Earth, delivering glancing blows to our planet's magnetic field. No single impact is expected to be strong, but the combined effect of multiple weak impacts could spark polar geomagnetic storms from Oct. 28th to Oct. 31st. High-latitude sky watchers should be alert for auroras. Aurora alerts: text, voice.
SOLAR ACTIVITY CONTINUES: Earth-orbiting satellites detected an X1-class solar flare from sunspot AR1875 on Oct. 28th at 0203 UT. This is the 3rd X-flare since Oct. 25th, which means solar activity is still high. NASA's Solar Dynamics Observatory recorded the flare's extreme UV flash:
SOHO recorded a CME emerging from the blast site: movie. Although it was heading mainly away from Earth, the CME could still deliver a glancing blow to our planet's magnetic field on Oct. 30th. NOAA analysts plan to issue an update later today. Solar flare alerts: text, voice.
SPACE WEATHER RADIATION BALLOON: According to a recent NASA report, astronauts aren't the only ones who need to worry about solar storms. Ordinary air travelers can also be exposed to significant doses of radiation when the sun is active. On Oct. 27th, the students of Earth to Sky Calculus launched an experiment to investigate the effects of space weather on aviation. Using a suborbital helium balloon, they sent a pair of radiation sensors to the stratosphere. The launch took place from their "edge of space port" in the Sierras of central California:
The payload was equipped to measure alpha and beta particles as well as X-rays and gamma rays at altitudes as high as 120,000 feet. After a two-hour flight, the payload has parachuted back to Earth. A recovery team will gather the sensors and begin analyzing the readings as early as Oct. 28th.
Another balloon flight could be in the offing. Active sunspots AR1875 and AR1877 are approaching the sun's western limb where they will become magnetically connected to Earth. Energetic particles accelerated by flares on that side of the sun are funneled back toward our planet by spiraling magnetic fields. The young scientists say that a radiation storm in the days ahead would prompt another trip to the stratosphere. Stay tuned. Solar flare alerts: text, voice.
Realtime Space Weather Photo Gallery
COMET LINEAR X1: The sun isn't the only thing exploding. Almost 450 million km from Earth, Comet C/2012 X1 (LINEAR) is having its own outburst. On Oct. 20th, amateur astronomers realized that the comet's brightness had increased 100-fold and its morphology resembled that of exploding Comet 17P/Holmes in 2007. Follow-up images in recent nights seem to show jet-like structures in Comet LINEAR X1's expanding atmosphere. Amateur astronomer Nick James of Chelmsford, UK, obtained these data on Oct. 26th:
Another set of images taken by James shows the comet's atmosphere or "coma" expanding over a period of two days. "The coma's diameter is increasing at a rate of 30 arcseconds per day," says James. "At a distance of 2.95 AU this corresponds to 65,000 km/day or a little less than 1 km/s." He made these observations using an 11-inch Celestron telescope.
Located in the constellation Coma Berenices, Comet LINEAR X1 rises in the east about an hour before the sun. The low altitude of the comet in morning twilight is a challenge, but because the comet is fairly bright, magnitude +8.5, it is still a relatively easy target for backyard telescopes equipped with digital cameras. Monitoring is encouraged! Resources: 3D orbit, ephemeris, sky map.
Realtime Comet Photo Gallery
Realtime Comet ISON 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 Oct. 28, 2013, the network reported 14 fireballs.
(12 sporadics, 2 Orionids)
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 October 28, 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 |