By Spaceweather.com, 08/13/2015
PERSEID METEOR SHOWER: The Perseid meteor shower is underway. Observers with the International Meteor Organization are reporting as many as 100 meteors per hour over very dark-sky sites. City dwellers are seeing reduced numbers because of urban light pollution; the countryside is better! Here’s a fun way to experience the Perseids: Listen to their radar echoes on Space Weather Radio.
Ronny Tertnes photographed these two Perseids over Bergen, Norway, on August 13th:
“I combined two images taken one minute apart,” says Tertnes. “One of the Perseids was a really bright fireball.”
Indeed, the Perseids produce more fireballs than any other meteor shower of the year. This is because the parent comet, 109P/Swift-Tuttle, is large and its debris stream is rich in fireball-producing “gravel.” The tendency of this shower to produce fireballs is why people in cities can see some Perseids in spite of street lights and other glare. The best time to look, no matter where you live, is during the hours just before sunrise when the constellation Perseus is high in the sky.
SPRITES ABOVE HURRICANE HILDA: On August 10th, the National Weather Service reported an intense outburst of lightning from Hurricane Hilda in the Pacific Ocean. Steve Cullen lives in Waikoloa, Hawaii, where the storm is heading, and when he heard the report he had an idea. Cullen explains: “I wondered if the storm was close enough to be captured by the Canada France Hawaii Telescope CloudCam atop Maunakea. After sunset I logged on to the CloudCam site to check the most recent two-hour timelapse loop, and sure enough, WE HAD SPRITES!!!” Here are some frames from the video:
Sprites are a strange and beautiful form of lightning that shoot up from the tops of electrical storms. They reach all the way up to the edge of space alongside meteors, auroras, and noctilucent clouds. Some researchers believe cosmic rays help trigger sprites, but this is controversial. In short, sprites are a true space weather phenomenon.
As awareness of sprites has increased in recent years, photographers have started to catch them dancing atop ordinary thunderstorms on a regular basis: photo gallery. Seeing sprites above a hurricane, however, is rare. Most hurricanes don’t even have regular lightning because the storms lack a key ingredient for electrical activity: vertical winds. (For more information read the Science@NASA article “Electric Hurricanes” by Patrick Barry and Dr.Tony Phillips.) Clearly, Hurricane Hilda is not a typical storm.
Stay tuned for more observations of Hilda’s cloudtops as it approaches Hawaii.
SOLAR RADIO BURSTS: For the past week, solar activity has been low. However, the sun has not been quiet. “I have noted that the sun has been extremely dynamic at shortwave radio wavelengths with almost constant Type III bursting,” reports Thomas Ashcraft of New Mexico. He has been hearing loud bursts of static coming from the loudspeaker of his amateur radio telescope whenever he points it at the sun. Click on the dynamic spectrum below to hear a sample:
Type III solar radio bursts are caused by solar flares. Electrons accelerated by strong flares race through the sun’s atmosphere, causing a ripple of plasma waves and radio static. Yet, ironically, there have been no strong solar flares. Nevertheless, suggests Ashcraft, “all of the bursting indicates a lot of magnetic complexity and movement in the sunspots.”
The biggest sunspot of all, AR2396, is about to rotate off the western edge of the sun. After it departs, the static might subside. Until then, shortwave radio operators should remain alert for solar bursts. The sun is not so quiet, after all. Solar flare alerts: text or voice
Realtime Space Weather Photo Gallery
All Sky Fireball Network
Every night, a network of NASA all-sky cameras scans the skies above the United States for meteoritic fireballs. Automated software maintained by NASA’s Meteoroid Environment Office calculates their orbits, velocity, penetration depth in Earth’s atmosphere and many other characteristics. Daily results are presented here on Spaceweather.com.
On Aug. 13, 2015, the network reported 383 fireballs.
(267 , 112 , 2 , 1 , 1 , 0 sporadics)
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 13, 2015 there were 1603 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Size
2015 PK9
Aug 7
5.8 LD
80 m
2015 PL9
Aug 8
1.2 LD
16 m
2005 JF21
Aug 16
20.1 LD
1.6 km
2004 BO41
Aug 31
57.3 LD
1.2 km
1991 CS
Sep 4
62.1 LD
1.4 km
2014 KS76
Sep 14
8.7 LD
22 m
2004 TR12
Sep 15
58.8 LD
1.0 km
2000 FL10
Oct 10
65.7 LD
1.9 km
2011 QD48
Oct 17
67.5 LD
1.0 km
2014 UR
Oct 18
3.8 LD
21 m
2011 SE97
Oct 18
12 LD
50 m
2001 UY4
Oct 21
58.2 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.
Current Conditions
Solar wind
speed: 361.1 km/sec
density: 4.7 protons/cm3
explanation | more data
Updated: Today at 1559 UT
X-ray Solar Flares
6-hr max: B5 1045 UT Aug13
24-hr: B5 1045 UT Aug13
explanation | more data
Updated: Today at: 1500 UT
Daily Sun: 12 Aug 15
Departing sunspot AR2396 poses a waning threat for M-class solar flares. Credit: SDO/HMI
Sunspot number: 68
What is the sunspot number?
Updated 12 Aug 2015
Spotless Days
Current Stretch: 0 days
2015 total: 0 days (0%)
2014 total: 1 day (<1%)
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%)
Updated 12 Aug 2015
The Radio Sun
10.7 cm flux: 103 sfu
explanation | more data
Updated 12 Aug 2015
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/Ovation
Planetary K-index
Now: Kp= 2 quiet
24-hr max: Kp= 4 unsettled
explanation | more data
Interplanetary Mag. Field
Btotal: 5.7 nT
Bz: 2.6 nT south
explanation | more data
Updated: Today at 1559 UT
Coronal Holes: 12 Aug 15
Solar wind flowing from the indicated coronal hole could reach Earth on Aug. 16th. Credit: SDO/AIA.
Noctilucent Clouds
The northern season for NLCs is underway. NASA’s AIM spacecraft spotted the first noctilucent clouds over the Arctic Circle on May 19th.
Switch view: Europe, USA, Asia, Polar
Updated at: 08-12-2015 17:55:03
NOAA Forecasts
Updated at: 2015 Aug 12 2200 UTC
FLARE
0-24 hr
24-48 hr
CLASS M
25 %
25 %
CLASS X
05 %
05 %
Geomagnetic Storms:
Probabilities for significant disturbances in Earth’s magnetic field are given for three activity levels: active, minor storm, severe storm
Updated at: 2015 Aug 12 2200 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
10 %
10 %
MINOR
01 %
01 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
15 %
15 %
MINOR
15 %
15 %
SEVERE
15 %
15 %
Space Weather Update: 08/13/2015
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