You are viewing the page for Aug. 7, 2009
  Select another date:
<<back forward>> -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
Current conditions
Solar wind
speed: 472.8 km/sec
density: 4.3 protons/cm3
explanation | more data
Updated: Today at 2346 UT
X-ray Solar Flares
6-hr max: A0
2340 UT Aug07
24-hr: A0
0700 UT Aug07
explanation | more data
Updated: Today at: 2340 UT
Daily Sun: 28 July 09
The sun is blank--no sunspots. Credit: SOHO/MDI

Note: Why is the 'daily sun' several days old? Solar and Heliospheric Observatory (SOHO) is having a minor problem. SOHO's white light solar telescope is temporarily offline while new commands and data tables are uploaded to the spacecraft. Normal operations are expected to resume in a few days.
Sunspot number: 0
What is the sunspot number?
Updated 06 Aug 2009

Spotless Days
Current Stretch: 27 days
2009 total: 169 days (78%)
Since 2004: 680 days
Typical Solar Min: 485 days
explanation | more info
Updated 06 Aug 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= 3 quiet
24-hr max: Kp= 3
explanation | more data
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Interplanetary Mag. Field
Btotal: 6.1 nT
Bz: 3.6 nT north
explanation | more data
Updated: Today at 2346 UT
Coronal Holes:
Earth is inside a solar wind stream flowing from the indicated coronal hole. Credit: SOHO Extreme UV Telescope
NOAA Forecasts
Updated at: 2009 Aug 07 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 Aug 07 2201 UTC
0-24 hr
24-48 hr
05 %
20 %
01 %
01 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
10 %
30 %
01 %
10 %
01 %
01 %
What's up in Space
August 7, 2009

KILLER APP: You can now experience the Perseid meteor shower on your iPhone. It's cloud-proof! Learn more and give it a try.


INTENSIFYING PERSEIDS: The Perseid meteor rate is increasing as Earth plunges deeper into the debris stream of Comet Swift-Tuttle. International Meteor Organization observers are now counting 20 per hour: data. Forecasters say the rate could increase another tenfold to 200 per hour on peak night, Aug. 11th and 12th. Observing tips may be found in the Science@NASA story "The Perseids are Coming."

HOW HIGH IS A PERSEID? Perseid meteors seem so nearby when they fly overhead, but appearances can be deceiving. Consider the following fireball, which lit up the sky above the Marshall Space Flight Center two nights ago:

NASA astronomer Bill Cooke photographed the Perseid using not one but two all-sky cameras located 100 miles apart. The system's wide baseline, which crosses state lines between Alabama and Georgia, allowed him to triangulate the meteor's position and measure its velocity. "It came in at 58.8 km/s (130,000 mph) and disintegrated between 111 and 86 km above Earth's surface," he says.

So far, the dual-camera system has captured seven bright Perseids suitable for analysis. Cooke's histograms of starting and ending heights answer the question, how high is a Perseid?

UPDATED: 2009 Perseid Photo Gallery
[previous Perseids: 2008, 2007, 2006, 2005, 2004, 2001]

PERSEID'S BANE: Poets, dreamers, the romantically smitten, they all admire the silvery light of a full Moon. It's a lovely sight--until the meteor shower starts. Imagine trying to count Perseids through a floodlight like this:

Jens Hackmann took the picture last night from Weikersheim, Germany. "Jupiter and the Moon were beautiful rising behind a local church tower," he says. If there were any meteors, however, moonlight blotted them out.

Fortunately, on Aug. 11-12 when the Perseid meteor shower peaks, the Moon will have waned to 55% of its current illumination. That's still a lot of moonlight, but not enough to completely spoil the show. Be alert for meteors next week!

more images: from Tamas Ladanyi of Veszprem, Hungary; from Ofer Gabzo of Givatayin, Israel; from Eric Soucy of Ohain, Brabant wallon, Belgium; from Bryan Tobias of Chicago, Illinois; from Mohamad Soltanolkottabi of Mahmudabad, Mazandaran, Iran; from Kevin Jung of Lowell Township, Michigan; from Zoltan Melkes of Kundl, Tyrol, Austria; from Ken Scott of Glen Arbor, Michigan; from Mahdi Zamani of Tehran, Iran; from Mark Seibold of Portland, Oregon;
from Mustafa Erol of Ankara, Turkey;

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

July 2009 Aurora Gallery
[previous Julys: 2008, 2007, 2006, 2005, 2004, 2003]

Explore the Sunspot Cycle

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 7, 2009 there were 1067 potentially hazardous asteroids.
August 2009 Earth-asteroid encounters:
Miss Distance
2009 MC9
Aug. 7
70.3 LD
1.2 km
2009 OF
Aug. 8
15.4 LD
220 m
2007 RQ17
Aug. 9
8.4 LD
130 m
2000 LC16
Aug. 17
75.6 LD
2.0 km
2006 SV19
Aug. 21
59.2 LD
1.3 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.
©2019 All rights reserved.