Listen to radar echoes from satellites and meteors, live on listener-supported Space Weather Radio.
| || |
POSSIBLE CME IMPACT ON MAY 17: A coronal mass ejection (CME) hurled into space by the X1-flare of May 15th might deliver a glancing blow to Earth's magnetic field on May 17th. NOAA forecasters estimate a 40% chance of polar geomagnetic storms when the cloud arrives. High-latitude sky watchers should be alert for auroras tonight. Aurora alerts: text, voice.
M3-FLARE: Sunspot AR1748 unleashed an M3-class solar flare on May 17th at 0858 UT: image. Although this is not the strongest flare we've seen from AR1748, it could be the most geoeffective. The sunspot is facing Earth more directly than before, and the explosion might have hurled a CME toward our planet. Stay tuned for updates. Solar flare alerts: text, voice.
To illustrate the scale of the sunspot, photographer Göran Strand of Frösön, Sweden, inserted Earth into a picture of AR1748 he took on May 16th:
The sunspot's primary dark cores are nearly as big as our planet. However, that doesn't make this a big sunspot. Other 'spots on the sun today are larger. AR1748 is not explosive because it is large, but rather because it has a complex magnetic field. Lines of magnetic force twisting above the spot are criss-crossing and re-connecting. That's how you make an X-flare.
All by itself, AR1748 has produced more X-flares than every other sunspot of the past year combined. In summary, AR1748 has given us an X1.7-class flare (0217 UT on May 13), an X2.8-class flare (1609 UT on May 13), an X3.2-class flare (0117 UT on May 14), and an X1-class flare (0152 on May 15). Solar flare alerts: text, voice.
Realtime Space Weather Photo Gallery
DISCONNECTION EVENT IN THE TAIL OF COMET LEMMON: Comet Lemmon (C/2012 F6), which is receding from the sun not far beyond the orbit of Earth, has just experienced a "disconnection event." A cloud of dusty plasma is propagating down the comet's tail, shown here in a photo taken by Paul Mortfield on May 15th:
"I was pretty surprised to see this disconnection event when I processed the images," says Mortfield. "The comet is a challenge to photograph because it is so low in the sky at the start of morning twilight."
Disconnection events can be caused by CME impacts. A famous example is that of Comet Encke in 2007. Comet Lemmon, however, is not on the same side of the sun as active sunspot AR1748. It's hard to see how the recent X-flares can be responsible. Nevertheless, solar activity is high, so now is a good time to monitor comet tails. They are very sensitive to stormy space weather.
Comet Lemmon is a pre-dawn object for observers in the northern hemisphere. It is currently gliding alongside the Great Square of Pegasus in the eastern sky before sunrise. The 7th-magnitude comet is too faint to see with the naked eye, but it is visible in medium-to-large backyard telescopes. Observers with computerized GOTO 'scopes should point their optics here.
More about Comet Lemmon: 3D orbit, ephemeris, light curves.
Realtime Comet Photo Gallery
Realtime Aurora Photo Gallery
Realtime Noctilucent Cloud Photo Gallery
[previous years: 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2011]