You are viewing the page for Jul. 31, 2013
  Select another date:
<<back forward>> -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids Internet Shopping Sites high quality binoculars excellent weather stations all-metal reflector telescopes rotatable microscopes
Solar wind
speed: 362.4 km/sec
density: 1.4 protons/cm3
explanation | more data
Updated: Today at 2347 UT
X-ray Solar Flares
6-hr max: B4
2045 UT Jul31
24-hr: C1
0519 UT Jul31
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 31 July 13
None of these sunspots is strongly flaring. Solar activity is low. Credit: SDO/HMI
Sunspot number: 105
What is the sunspot number?
Updated 31 Jul 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

31 Jul 2013

The Radio Sun
10.7 cm flux: 113 sfu
explanation | more data
Updated 31 Jul 2013

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Planetary K-index
Now: Kp= 2 quiet
24-hr max: Kp= 2
explanation | more data
Interplanetary Mag. Field
Btotal: 5.3 nT
Bz: 1.4 nT south
explanation | more data
Updated: Today at 2346 UT
Coronal Holes: 31 Jul 13
Solar wind flowing from this coronal hole could brush against Earth's magnetic field on August 3-4. 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: 07-31-2013 12:55:02
NOAA Forecasts
Updated at: 2013 Jul 31 2200 UTC
0-24 hr
24-48 hr
10 %
10 %
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 Jul 31 2200 UTC
0-24 hr
24-48 hr
10 %
15 %
01 %
05 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
15 %
15 %
20 %
25 %
10 %
25 %
Wednesday, Jul. 31, 2013
What's up in space

Listen to radar echoes from satellites and meteors, live on listener-supported Space Weather Radio.

Spaceweather Radio is on the air

MOSTLY QUIET: Solar activity remains low. The only action on the Earthside of the sun is a minor crackling of C-class solar flares from departing sunspot AR1800. NOAA forecasters estimate a 10% chance of M-class flares and no more than a 1% chance of X-flares on July 31st. Solar flare alerts: text, voice.

METEOR ACTIVITY PICKS UP: The Canadian Meteor Orbit Radar (CMOR) is scanning the skies over North America for signs of meteor activity. This all-sky map produced during the early hours of July 31st shows an active radiant in the constellation Aquarius:

"SDA" is the three-letter code for the Southern Delta Aquariid meteor shower, which occurs every year in late July when Earth passes through a stream of debris from comet 96P/Machholz. Observers are reporting more than a dozen meteors per hour from this radiant. They are best seen from the southern hemisphere during the dark hours between midnight and dawn.

The complete radar map shows another more significant radiant coming to life. Click here and look for "PER." The annual Perseid meteor shower is just getting started as Earth enters the outskirts of a debris stream from big comet 109P/Swift-Tuttle. Forecasters expect the shower to peak on August 12-13 with ~100 meteors per hour, an order of magnitude stronger than the Southern Delta Aquariids. Stay tuned.

Realtime Meteor Photo Gallery

NOCTILUCENT CLOUDS: Sky watchers across northern Europe are reporting a vivid display of noctilucent clouds on July 31st. Nické Eriksson sends this sunset image from Karlstad, Sweden:

"It reminded me of a magic carpet," says Eriksson.

Normally the coming of August signals a downturn in sightings of noctilucent clouds (NLCs). The northern noctilucent daisy is brightest in June and July. This year, however, might be different. So far, 2013 has been one of the best years ever for these strange clouds at the edge of space. Sightings could continue long after than usual end of NLC season.

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 tendrils spreading across the sky, you've probably spotted a noctilucent cloud.

Realtime Space Weather Photo Gallery

Realtime Aurora 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 July 31, 2013 there were 1397 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
2006 BL8
Jul 26
9.3 LD
48 m
2003 DZ15
Jul 30
9.1 LD
152 m
2005 WK4
Aug 9
8.1 LD
420 m
1999 CF9
Aug 23
24.7 LD
1.1 km
2002 JR9
Aug 31
63.5 LD
1.4 km
1992 SL
Sep 23
70 LD
1.1 km
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...
©2010 All rights reserved. This site is penned daily by Dr. Tony Phillips.
©2013 All rights reserved.