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<<back forward>> -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
Current conditions
Solar wind
speed: 369.1 km/sec
density: 2.2 protons/cm3
explanation | more data
Updated: Today at 2345 UT
X-ray Solar Flares
6-hr max: A0
2340 UT Apr13
24-hr: A0
1315 UT Apr13
explanation | more data
Updated: Today at: 2340 UT
Daily Sun: 13 Apr 09
The sun is blank--no sunspots. Credit: SOHO/MDI
Sunspot number: 0
What is the sunspot number?
Updated 13 Apr 2009

NEW: Spotless Days
Current Stretch: 18 days
2009 total: 90 days (87%)
Since 2004: 601 days
Typical Solar Min: 485 days
explanation | more info
Updated 13 Apr 2009

Far side of the Sun:
This holographic image reveals no sunspots on the far side of the sun. Image credit: SOHO/MDI
Planetary K-index
Now: Kp= 0 quiet
24-hr max: Kp= 2
explanation | more data
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
What is the auroral oval?
Interplanetary Mag. Field
Btotal: 1.6 nT
Bz: 0.7 nT south
explanation | more data
Updated: Today at 2346 UT
Coronal Holes:
A solar wind stream flowing from the indicated coronal hole could reach Earth on April 15th or 16th. Credit: SOHO Extreme UV Telescope
NOAA Forecasts
Updated at: 2009 Apr 13 2201 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: 2009 Apr 13 2201 UTC
0-24 hr
24-48 hr
05 %
05 %
01 %
01 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
05 %
05 %
01 %
01 %
01 %
01 %
What's up in Space
April 13, 2009

AURORA ALERT: Did you sleep through the Northern Lights? Next time get a wake-up call: Spaceweather PHONE.


APOPHIS PRE-ANNIVERSARY: Twenty years from today, on April 13th, 2029, asteroid Apophis will buzz Earth only 18,300 miles above the planet's surface--well inside the belt of geosynchronous communications satellites. At closest approach, the 300-meter-wide asteroid will shine like a 3rd magnitude star, visible to the unaided eye from cities in Africa, Europe and Asia. There is a small chance (1 in 45,000) that the 2029 encounter will bend the asteroid's orbit so that it returns to Earth and actually hits the planet on April 13th, 2036. Experts believe that future observations will probably rule out a collision. Nevertheless, NASA and others are thinking about asteroid deflection strategies ... just in case.

RADIO STORMS ON JUPITER: On April 11th, the loudspeaker of Thomas Ashcraft's 21 MHz radio telescope in New Mexico suddenly began to hiss and crackle. The sounds grew louder as Jupiter rose in the blue morning sky. "I am pleased to report," says Ashcraft, "a successful recording of Jovian S-bursts--the first of 2009." Click on the image to listen:

The staccato pops sound like lightning in the loudspeaker of a car radio, but lightning did not make these sounds. S-bursts are caused by natural radio lasers in Jupiter's magnetosphere that sweep past Earth as Jupiter rotates. Electrical currents flowing between Jupiter's upper atmosphere and the volcanic moon Io can boost these emissions to power levels easily detected by ham radio antennas on Earth. Jovian S-bursts and L-bursts can mimic the sounds of woodpeckers, whales, and waves crashing on the beach. Here are a few audio samples: S-bursts, S-bursts (slowed down 128:1), L-Bursts

"I recorded the storm in broad daylight," notes Ashcraft. "One of the advantages of this long solar minimum is that the daytime ionosphere is quieter and more transparent to decametric radio waves. There will definitely be more good Jupiter storms in the months to come." Stay tuned!

SUNDOGS AND DONKEY SHADOWS: The next time you're out walking on a sunny day and you meet a donkey, duck into its shadow. It's a great place to find rings around the sun:

Yesterday, Erwan Henry of Carnac, France, followed those instructions and found five different ice haloes: "I saw a parhelic circle with sundogs, a 22o sun halo, an upper tangent arc and an infralateral arc. I was so happy to see an entire parhelic circle for the first time!"

Halos like these are often overhead--and just as often overlooked because there is nothing handy to block the glare. Can't find a donkey? Fingers, trees, flags and weather globes work, too. Take a look!

Explore the Sunspot Cycle

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

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 13, 2009 there were 1050 potentially hazardous asteroids.
April 2009 Earth-asteroid encounters:
Miss Distance
2009 FU30
Apr. 2
8.8 LD
44 m
2004 VC
Apr. 3
51.3 LD
785 m
2002 EB3
Apr. 10
41.3 LD
1.3 km
2003 SG170
Apr. 19
57.7 LD
1.2 km
2009 FJ30
Apr. 24
9.7 LD
130 m
2001 VG5
Apr. 26
58.5 LD
2.1 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 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 and Heliospheric Observatory
  Realtime and archival images of the Sun from SOHO.
  3D views of the sun from NASA's Solar and Terrestrial Relations Observatory
Daily Sunspot Summaries
  from the NOAA Space Environment Center
Current Solar Images
  from the National Solar Data Analysis Center
Science Central
  more links...
©2008, -- This site is penned daily by Dr. Tony Phillips.
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