CALM BEFORE THE STORM? Big sunspot AR1520 has been relatively quiet for the past 48 hours, but this could be the calm before the storm. The sunspot has a delta-class magnetic field that harbors energy for X-class solar flares. Solar flare alerts: text, voice.
NOCTILUCENT CLOUDS: This morning a vast bank of electric-blue noctilucent clouds rippled across northern Europe. "It was like water in the sky," says Barbara Grudzinska, who photographed the display from Warsaw, Poland:
"These are the first noctilucent clouds this year so clearly visible at our latitude in Warsaw (52 N)," says Grudzinska.
When NLCs first appeared in the 19th century, the mysterious clouds were confined to the Arctic, most often seen in the same places as Northern Lights. In recent years, however, their "habitat" has been expanding, rippling as far south as Colorado, Virginia, Kansas, and Utah. (Here are some examples of sightings in the lower United States.) There is growing evidence that the expansion is a sign of climate change, although this remains controversial.
Whatever the reason, noctilucent clouds aren't just at high latitudes anymore, so sky watchers everywhere should be alert for them. Observing tips: Look west 30 to 60 minutes after sunset when the sun has dipped 6o to 16o below the horizon. If you see luminous blue-white
Solar wind
speed: 416.2 km/sec
density: 0.5 protons/cm3
explanation | more data
Updated: Today at 1436 UT
X-ray Solar Flares
6-hr max: C3 0805 UT Jul12
24-hr: C4 0136 UT Jul12
explanation | more data
Updated: Today at: 1400 UT
Daily Sun: 12 Jul 12
Sunspot 1520 has a delta-class magnetic field that harbors energy for X-class solar flares. Credit: SDO/HMI
Sunspot number: 94
What is the sunspot number?
Updated 12 Jul 2012
Spotless Days
Current Stretch: 0 days
2012 total: 0 days (0%)
2011 total: 2 days (<1%)
2010 total: 51 days (14%)
2009 total: 260 days (71%)
Since 2004: 821 days
Typical Solar Min: 486 days
Updated 12 Jul 2012
The Radio Sun
10.7 cm flux: 162 sfu
explanation | more data
Updated 12 Jul 2012
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/POES
Planetary K-index
Now: Kp= 3 quiet
24-hr max: Kp= 4 unsettled
explanation | more data
Interplanetary Mag. Field
Btotal: 4.0 nT
Bz: 3.7 nT north
explanation | more data
Updated: Today at 1436 UT
Coronal Holes: 12 Jul 12
There are no large coronal holes on the Earthside of the sun. Credit: SDO/AIA
