You are viewing the page for Jan. 21, 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: 405.8 km/sec
density: 3.8 protons/cm3
explanation | more data
Updated: Today at 2345 UT
X-ray Solar Flares
6-hr max: A0
2340 UT Jan21
24-hr: A0
2340 UT Jan21
explanation | more data
Updated: Today at: 2340 UT
Daily Sun: 21 Jan 09
The sun is blank--no sunspots. Credit: SOHO/MDI
Sunspot number: 0
What is the sunspot number?
Updated 20 Jan. 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
What is the auroral oval?
Interplanetary Mag. Field
Btotal: 2.6 nT
Bz: 1.4 nT north
explanation | more data
Updated: Today at 2346 UT
Coronal Holes:
A solar wind stream flowing from the indicated coronal hole should reach Earth on or about Jan. 25th. Credit: SOHO Extreme UV Telescope
SPACE WEATHER
NOAA Forecasts
Updated at: 2009 Jan 21 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 Jan 21 2201 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
01 %
01 %
MINOR
01 %
01 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
05 %
05 %
MINOR
01 %
01 %
SEVERE
01 %
01 %
What's up in Space
January 21, 2009

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

 

COMET LULIN UPDATE: "Right now, Comet Lulin (C/2007 N3) is an easy target for binoculars and small telescopes," reports Mariano Ribas of Buenos Aires, Argentina. "It is visible despite our strong urban light pollution. I have been observing the comet during the hours before dawn and estimate its visual magnitude as +7. Maybe this will not be a 'great' comet like McNaught was two years ago, but I look forward to a good show in the weeks ahead as Comet Lulin approaches Earth." [gallery] [sky map] [finder chart]

HUBBLE FLARE: The Hubble Space Telescope is not the brightest light in the night sky. Soaring overhead, it typically shines like a 2nd magnitude star, a pinprick of middling luminosity and nothing to get excited about--that is, not until it flares. "Last night, I saw the Hubble brighten dramatically," reports Mark Staples of Waldo, Florida. "It was almost as bright as Venus." He captured the flare during an 82-second exposure with his Canon 30D:

Hubble flares have been observed before. They are caused by sunlight glinting off the flat back surface of the spacecraft where the primary mirror is located. The sudden glints are practically impossible to predict. They depend not only on the ever-changing shape of the Sun-Earth-Hubble triangle, but also on the details of Hubble's observing schedule. The pointing of the telescope determines how the back-plane is tilted and, thus, the possibility of a flare. The only way to catch one is to spend time looking.

Check the Simple Satellite Tracker to find out when Hubble is going to fly over your backyard. You may be in for a pleasant surprise!

LEE WAVE IRIDESCENCE: Invisible to the human eye, air flowing over the Rocky Mountains bobs up and down in giant waves known as lee waves. On Jan. 2nd, these waves became temporarily visible when clouds caught in the wave-pattern lit up with beautiful iridescence:

"The pastel colors were lovely and the billowing cloud shapes were quite fascinating," says photographer Harold Leinbach of Boulder, Colorado. "I took the picture using my Canon Rebel XT."

Iridescence is caused by droplets of water diffracting sunlight. We often see hints of iridescent color in ordinary clouds far from mountain ranges. Lee waves intensify the phenomenon, creating a sky-wide tableau of vivid pastel.

Atmospheric optics expert Les Cowley explains: "For brightly-colored iridescence you need cloud droplets of all the same size. You get that if all the droplets have formed at the same time and experienced the same history. Dynamic conditions inside a lee cloud are just what the doctor ordered. The clouds look stationary but inside there is a 'factory conveyor' with uniform droplets formed at one end and evaporated at the other. Voila - iridescence."

Lee waves may be found downwind of all mountains--not just the Rockies. If you live in the lee, keep an eye out for pastels in the sky.



Jan. 2009 Aurora Gallery
[Previous Januaries: 2008, 2007, 2005, 2004, 2001]
       
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 January 21, 2009 there were 1017 potentially hazardous asteroids.
Jan. 2009 Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Mag.
Size
2008 YC29
Jan. 2
3.4 LD
18
35 m
2008 YY32
Jan. 3
6.2 LD
18
40 m
2008 YG30
Jan. 4
3.6 LD
16
50 m
2008 YV32
Jan. 9
2.7 LD
19
25 m
2008 YF29
Jan. 11
9.7 LD
18
65 m
2002 AO11
Jan. 15
7.7 LD
17
120 m
1998 CS1
Jan. 17
11 LD
12
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.