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<<back forward>> -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
Solar wind
speed: 477.2 km/sec
density: 0.0 protons/cm3
explanation | more data
Updated: Today at 2343 UT
X-ray Solar Flares
6-hr max: B5
1713 UT Apr04
24-hr: B8
0447 UT Apr04
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 04 Apr 11
New sunspot 1184 is growing but does not yet pose a threat for strong flares. Credit: SDO/HMI
Sunspot number: 70
What is the sunspot number?
Updated 03 Apr 2011

Spotless Days
Current Stretch: 0 days
2011 total: 1 day (1%)
2010 total: 51 days (14%)
2009 total: 260 days (71%)
Since 2004: 820 days
Typical Solar Min: 486 days

Updated 03 Apr 2011

The Radio Sun
10.7 cm flux: 114 sfu
explanation | more data
Updated 03 Apr 2011

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Planetary K-index
Now: Kp= 1 quiet
24-hr max: Kp= 3
explanation | more data
Interplanetary Mag. Field
Btotal: 3.2 nT
Bz: 0.2 nT south
explanation | more data
Updated: Today at 1820 UT
Coronal Holes: 04 Apr 11
There are no large coronal holes on the Earth-side of the sun. Credit: SDO/AIA.
NOAA Forecasts
Updated at: 2011 Apr 04 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: 2011 Apr 04 2200 UTC
0-24 hr
24-48 hr
10 %
10 %
01 %
01 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
15 %
15 %
01 %
01 %
01 %
01 %
Monday, Apr. 4, 2011
What's up in space

Are we alone? Your iPhone has the answer. Download the all-new Drake Equation app to calculate the population of the Milky Way.

DrakeEQ for iPhone and iPad

BRIGHT CME: NASA twin STEREO spacecraft observed a spectacular coronal mass ejection launched from the vicinity of decaying sunspot 1176 on April 3rd around 0500 UT. The blast was not Earth directed. Nevertheless, there is a chance that the expanding cloud will deliver a glancing blow to Earth's magnetic field on or about April 6th. CME movies: STEREO-A, STEREO-B.

DEEP SKY AURORAS: This weekend, April 2-3, Northern Lights spilled across the Canadian border into the United States with sightings as far south as Wisconsin, Minnesota, and Michigan. To the naked eye, the auroras were mostly pale-white, but exposures of 10 or more seconds with off-the-shelf digital cameras revealed spectacular color. Brian Larmay sends this picture from Pembine, WI:

"It has been a while since the auroras visited my latitude. Finally, the dry spell is over!" says Larmay. "Although dim, the lights showed up rather well on my Canon 40D."

These are called "deep sky auroras" because like other deep-sky objects (e.g., galaxies and nebulae) they are best seen using optics and timed exposures. More of them could be in the offing. For the third night in a row, a solar wind stream is buffeting Earth's magnetic field. Moreover, the Moon is new, so the night sky is dark enough for long exposures. Photographers, grab your cameras and be alert for auroras.

A note to Spaceweather PHONE subscibers: Deep-sky auroras occur mainly during weak geomagnetic storms. To maximize your chances of photographing the phenomenon, log into your Spaceweather PHONE account and reduce your Kindex alert threshold to 5. If you've forgotten how to adjust your settings, contact our help desk.

NEW: April 2011 Aurora Gallery
[previous Aprils: 2010, 2009, 2008, 2007, 2006, 2005, 2004, 2003, 2002]

SECRET SPACE PLANE FLARES: The US Air Force's X-37B space plane is circling Earth and, although it is on a classified mission with an officially unpublished orbit, sky watchers have spotted it. "I saw the X-37B from my home in Pasadena, California, around sunrise on March 31st," reports Anthony Cook of the Griffith Observatory. "The spacecraft's appearance was remarkable. When overhead it was a little brighter than a 2nd magnitude star with a slight yellow hue. Then it flared. As the X-37B moved toward the horizon it became silvery and brightened to around magnitude -6, far outshining Venus below it." The flare was presumably caused by sunlight glinting from some flat surface on the shuttle-shaped spacecraft, but no one can say for sure because it is a classified mission. Ready for a secret flare of your own? Space plane flyby preditions may be found on the Simple Satellite Tracker or on your cell phone.

SATURN'S RINGS SURGE IN BRIGHTNESS: This Sunday, April 3rd, Saturn is "at opposition"--that is, opposite the sun in the skies of Earth. Whenever this happens, Saturn's rings surge in brightness. Why? Scroll down for the explanation; on the way, inspect this photo taken by Paul Haese of South Australia on March 30th:

"This is how Saturn looked through my 14-inch telescope," says Haese. "With opposition so close, the Seeliger effect is really starting to show itself. The rings are much more spectacular than in previous years."

The Seeliger effect, also known as the opposition effect, is what brightens the rings. Saturn's rings are made of frozen chunks ranging in size from dust to houses. Sunlight directly backscattered from those ice particles causes the ring system to shine even more than usual for a few days around opposition. The exact mechanism involves shadow-hiding and possibly coherent backscattering.

To find Saturn, go outside at midnight and look for a conspicuous yellow "star" in the constellation Virgo. Even a small telescope will show Saturn's brightening rings. [sky map]

more images: from Efrain Morales Rivera of Aguadilla, Puerto Rico; from Christopher Go of Cebu City, Philippines

  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 April 4, 2011 there were 1215 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
2011 FA23
Apr 1
2.1 LD
7 m
2011 FT9
Apr 1
7.5 LD
25 m
2011 FT29
Apr 7
6.2 LD
36 m
2011 GZ2
Apr 9
2.7 LD
26 m
2011 FT53
Apr 9
6 LD
34 m
2011 GE
Apr 12
4.7 LD
28 m
2002 DB4
Apr 15
62.5 LD
2.2 km
2011 GJ3
Apr 27
7.8 LD
24 m
2008 UC202
Apr 27
8.9 LD
10 m
2009 UK20
May 2
8.6 LD
23 m
2008 FU6
May 5
75.5 LD
1.2 km
2003 YT1
May 5
65.3 LD
2.5 km
2002 JC
Jun 1
57.5 LD
1.6 km
2009 BD
Jun 2
0.9 LD
9 m
2002 JB9
Jun 11
71.5 LD
3.2 km
2001 VH75
Jun 12
42.2 LD
1.1 km
2004 LO2
Jun 15
9.9 LD
48 m
2001 QP181
Jul 2
35.1 LD
1.1 km
2003 YS117
Jul 14
73.9 LD
1.0 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
Conquest Graphics
  for out-of-this-world printing and graphics
Science Central
  more links...
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