You are viewing the page for Aug. 18, 2009
  Select another date:
<<back forward>>
SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
SPACE WEATHER
Current conditions
Solar wind
speed: 340.4 km/sec
density: 5.8 protons/cm3
explanation | more data
Updated: Today at 2346 UT
X-ray Solar Flares
6-hr max: A0
2340 UT Aug18
24-hr: A0
2340 UT Aug18
explanation | more data
Updated: Today at: 2340 UT
Daily Sun: 18 Aug 09
The sun is blank--no sunspots. Photo credit: Howard Eskildsen, Ocala, Florida
Sunspot number: 0
What is the sunspot number?
Updated 17 Aug 2009

Spotless Days
Current Stretch: 38 days
2009 total: 180 days (79%)
Since 2004: 691 days
Typical Solar Min: 485 days
explanation | more info
Updated 17 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= 1 quiet
24-hr max: Kp= 1
quiet
explanation | more data
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/POES
Interplanetary Mag. Field
Btotal: 4.5 nT
Bz: 1.5 nT south
explanation | more data
Updated: Today at 2347 UT
Coronal Holes:
A solar wind stream flowing from the indicated coronal hole should reach Earth on or about Aug. 19th. Credit: SOHO Extreme UV Telescope
SPACE WEATHER
NOAA Forecasts
Updated at: 2009 Aug 18 2201 UTC
FLARE
0-24 hr
24-48 hr
CLASS M
01 %
01 %
CLASS X
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 18 2201 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
30 %
25 %
MINOR
10 %
05 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
40 %
30 %
MINOR
20 %
10 %
SEVERE
05 %
01 %
What's up in Space
August 18, 2009

AURORA ALERT: Did you miss the Northern Lights? In July they descended as far south as Nebraska. Next time get a wake-up call: Spaceweather PHONE.

 

BEWARE THE MARS HOAX: If you have marked your calendar for August 27th to remind yourself to watch Mars swell to the size of a full Moon, go back and add these words: Mars Hoax! Contrary to a widespread email alert, Mars will not come close to Earth on August 27th and it can never rival the full Moon in the night skies of our planet. Science@NASA has the full story.

JUPITER MOON MOVIE: Four hundred years ago when Galileo discovered the moons of Jupiter, the satellites appeared in his primitive telescope as tiny, almost infinitesimal specks of light pirouetting around the giant planet. Their discovery transformed 17th century cosmology and made Galileo famous, but he never saw them as anything more than star-like pinpricks. The "Galilean satellites" were second-class citizens in the heirarchy of known worlds.

What would Galileo say now?

On August 16th, Philippine astrophotographer Christopher Go used a modern 11-inch Celestron telescope to photograph Io casting its shadow on Ganymede. Click on the image to launch the movie:

"I captured this rare event through a hole in the clouds," says Go. "It was a lucky clearing!"

In the movie, Io and Ganymede reveal themselves as fully-formed worlds with surface markings and a spherical shape. Io's circular shadow cuts a dark swath across Ganymede, transforming that giant moon (it is larger than Mercury) into a succession of crescents rarely seen by observers. Indeed, as far as we know, no telescope on Earth or space has ever photographed one of Jupiter's moons casting its circular shadow so clearly across another.

"While imaging the shadow transit, I took the time to photograph Jupiter itself," says Go. "The Great Red Spot, an anticyclone twice the size of Earth, was very prominent."

At this point, one imagines Galileo would jump up and exclaim--"bring me a telescope!" If only we could. August 2009 is a superb time to watch the giant planet. Jupiter is at its closest to Earth and outshines every star in the night sky. Backyard optics reveal giant storms, clouds, moons, moon shadows and occasionally an explosive surprise. The place to look is here.

PERSIAN DAWN: This morning in Iran, Venus and the Moon got together and with their combined luminosity rivaled the city lights of Tehran itself. Oshin D. Zakarian sends this photo from a hilltop overlooking the city:

.

"The elegant crescent Moon was only 3o away from dazzling Venus in the morning sky," says Babak Tafreshi who admired the view alongside Zakarian. "The pair were visible even through clouds."

Scenes like this are worth waking up for. The next Venus-Moon pairing is less than a month away--on Wednesday morning, Sept 16th. Get a reminder call from Spaceweather PHONE.

more images: from Tunç Tezel of Pamukkale, Turkey; from Amir H. Abolfath of Persepolise, Fars, Iran; from Danny Ratcliffe of Deception Bay, QLD Australia; from Mohamad Soltanolkottabi of Esfahan, Iran; from Babak Tafreshi of Lavasan, Alborz Mountains, Iran; from Ugur Ikizler of Mudanya - Bursa / Turkey; from Achim Schaller of Marzell, Black Forest, Germany;


2009 Perseid Photo Gallery
[Science@NASA: The Perseids are Coming, Horse Flies and Meteors]


2009 Noctilucent Photo Gallery
[previous years: 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 18, 2009 there were 1067 potentially hazardous asteroids.
August 2009 Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Mag.
Size
2009 MC9
Aug. 7
70.3 LD
16
1.2 km
2009 OF
Aug. 8
15.4 LD
18
220 m
2007 RQ17
Aug. 9
8.4 LD
17
130 m
2000 LC16
Aug. 17
75.6 LD
14
2.0 km
2006 SV19
Aug. 21
59.2 LD
16
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.
STEREO
  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, SpaceWeather.com -- This site is penned daily by Dr. Tony Phillips.
©2013 Spaceweather.com. All rights reserved.