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Solar wind
speed: 405.7 km/sec
density: 2.4 protons/cm3
explanation | more data
Updated: Today at 2347 UT
X-ray Solar Flares
6-hr max: B3
2100 UT Aug28
24-hr: B3
1626 UT Aug28
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 28 Aug 13
None of these sunspots poses a threat for strong solar flares. Credit: SDO/HMI
Sunspot number: 61
What is the sunspot number?
Updated 28 Aug 2013

Spotless Days
Current Stretch: 0 days
2013 total: 0 days (0%)
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

28 Aug 2013

The Radio Sun
10.7 cm flux: 110 sfu
explanation | more data
Updated 28 Aug 2013

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Planetary K-index
Now: Kp= 1 quiet
24-hr max: Kp= 4
explanation | more data
Interplanetary Mag. Field
Btotal: 1.8 nT
Bz: 0.4 nT north
explanation | more data
Updated: Today at 2347 UT
Coronal Holes: 28 Aug 13
Solar wind flowing from the indicated coronal hole should reach Earth on Aug. 30-31. Credit: SDO/AIA. is now posting daily satellite images of noctilucent clouds (NLCs), which hover over Earth's poles at the edge of space. The data come from NASA's AIM spacecraft. The north polar "daisy" pictured below is a composite of near-realtime images from AIM assembled by researchers at the University of Colorado's Laboratory for Atmospheric and Space Physics (LASP).
Noctilucent Clouds
Switch view: Europe, USA, Asia, Polar
Updated at: 08-28-2013 10:55:02
NOAA Forecasts
Updated at: 2013 Aug 27 2300 UTC
0-24 hr
24-48 hr
01 %
01 %
01 %
01 %
Geomagnetic Storms:
Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm
Updated at: 2013 Aug 27 2300 UTC
0-24 hr
24-48 hr
15 %
15 %
01 %
01 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
15 %
15 %
25 %
25 %
20 %
20 %
Wednesday, Aug. 28, 2013
What's up in space

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.

Northern Lights - a Guide

DAYTIME METEOR OUTBURST: Peter Brown of the University of Western Ontario reports an ourburst of Daytime Craterid meteors on August 28th. "The Canadian Meteor Orbit Radar is detecting about 20 meteors per hour (ZHR)," he says. "This is the first time in five years this has happened." The source of the shower is Comet Boattini (C/2007 W1). Because the comet's debris stream comes close to Earth, Jupiter and Saturn, it experiences gravitational perturbations which make the shower highly variable. Try listening to the Daytime Craterids on Space Weather Radio.

SUMMER LIGHTS: "Last night, the sky exploded into an inferno of vivid colours!" reports Oskar Pettersson of LuleƄ, Sweden. "It was the Northern Lights!" Pettersson saw the display after he walked out of a movie theatre, then rushed home to grab his camera for this shot:

"Aurora season has started with a bang, and now I'm really looking forward to seeing the rest of it!" he says.

The display began when the interplanetary magnetic field (IMF) around Earth tilted south. This opened a crack in Earth's magnetosphere. Solar wind flowed in and ignited the auroras. This disturbance is subsiding now but it is not over. NOAA forecasters estimate a 20% chance of polar geomagnetic storms on August 28th. Aurora alerts: text, voice.

Realtime Aurora Photo Gallery

SPACE WEATHER RADIO UPDATE: As a result of indiscriminate "sequester" budget cuts, the USAF Space Surveillance Radar will be shut down at the end of September. Readers have asked what this means for Space Weather Radio. For years we have broadcast Space Surveillance Radar echoes from meteors passing over the facility. Anticipating the shutdown, our radio engineer Stan Nelson is changing frequencies. "I have erected a new 50 MHz 4-element beam antenna for the Digital TV carrier of 54.310 MHz and have it feeding the receiver at," he explains. The echoes we hear now will be TV signals bouncing off the ionized trails of meteors. "I will be experimenting with the direction and signal strength over the next couple of days, so stay tuned."

NORTHERN CORONAL HOLE: Magnetic fields in the sun's northern hemisphere have opened up, creating a hole in the sun's upper atmosphere. This August 27th image from NASA's Solar Dynamics Observatory shows how solar wind is streaming out of the coronal hole:

The solar wind stream is heading for Earth, due to arrive on August 30-31. Its impact will not be a major event. Nevertheless, it could spark geomagnetic storms and auroras at high latitudes. This is good news around the Arctic Circle where the midnight sun is setting. Darkening skies will allow auroras to be seen for the first time in months. Browse the aurora gallery for a preview.

Realtime Space Weather Photo Gallery

Realtime Noctilucent Cloud Photo Gallery
[previous years: 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2011]

Realtime Comet Photo Gallery

  Near Earth Asteroids
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 August 28, 2013 there were 1422 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
1999 CF9
Aug 23
24.7 LD
1.1 km
2013 QR1
Aug 25
8.2 LD
215 m
2002 JR9
Aug 31
63.5 LD
1.4 km
2000 DK79
Nov 10
49.1 LD
3.2 km
2011 JY1
Nov 13
8.2 LD
57 m
2001 AV43
Nov 18
2.9 LD
58 m
2010 CL19
Nov 25
37.6 LD
1.3 km
2013 NJ
Nov 26
2.5 LD
180 m
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.
  Essential web links
NOAA Space Weather Prediction Center
  The official U.S. government space weather bureau
Atmospheric Optics
  The first place to look for information about sundogs, pillars, rainbows and related phenomena.
Solar Dynamics Observatory
  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
Solar and Heliospheric Observatory
  Realtime and archival images of the Sun from SOHO.
Daily Sunspot Summaries
  from the NOAA Space Environment Center
  the underlying science of space weather
Space Weather Alerts
  more links...
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