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You are viewing the page for Dec. 20, 2009

SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids

SPACE WEATHER
Current conditions

Solar wind
speed: 328.2 km/sec
density: 1.5 protons/cm³
explanation | more data
Updated: Today at 2345 UT

X-ray Solar Flares
6-hr max: B2 2325 UT Dec20
24-hr: B2 2325 UT Dec20
explanation | more data
Updated: Today at: 2340 UT

Daily Sun: 20 Dec. 09

All three of these sunspots are members of new Solar Cycle 24. The image is purple because was taken through a violet Calcium-K filter sensitive to the light emitted by magnetic froth around sunspots. Image credit: Stefano Sello of Pisa, Italy

Sunspot number: 43
What is the sunspot number?
Updated 19 Dec 2009

Spotless Days
Current Stretch: 0 days
2009 total: 259 days (73%)
Since 2004: 770 days
Typical Solar Min: 485 days
explanation | more info
Updated 19 Dec 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= 1 quiet
explanation | more data

Current Auroral Oval:

Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/POES

Interplanetary Mag. Field
B_total: 1.6 nT
B_z: 0.5 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 or about Dec. 22nd. Credit: SOHO Extreme UV Telescope

SPACE WEATHER
NOAA Forecasts

Updated at: 2009 Dec 20 2201 UTC

FLARE	0-24 hr	24-48 hr
CLASS M	10 %	05 %
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 Dec 20 2201 UTC

Mid-latitudes

	0-24 hr	24-48 hr
ACTIVE	10 %	05 %
MINOR	01 %	01 %
SEVERE	01 %	01 %

High latitudes

	0-24 hr	24-48 hr
ACTIVE	15 %	05 %
MINOR	01 %	01 %
SEVERE	01 %	01 %

What's up in Space

December 20, 2009

ASTRONOMY ALERTS: Looking for a unique and affordable gift? Give the heavens for Christmas at Spaceweather PHONE.

DECEMBER SOLSTICE: The December solstice occurs on Monday, Dec. 21st, at 1747 UT (12:47 pm EST) when the sun dips to its lowest celestial latitude of the year. The event marks the beginning of summer in the southern hemisphere and winter in the northern hemisphere--and some wonderful sunsets at Stonehenge. Happy Solstice!

SUNSET SKY SHOW: When the sun sets tonight, go outside and look up. Jupiter and the crescent Moon will be shining side-by-side in the southwestern sky. P-M Hedén sends this photo of his children enjoying the view from Vallentuna, Sweden:

Advice: Look before the sky fades all the way to black. A bright conjunction of worlds framed by twilight blue is an especially lovely sight. [sky map]

more images: from Rafael Schmall of Hungary, Somogy, Kaposfo; from Mark Claudel Arzadon of San Jacinto, Pangasinan, Philippines; from Geir Øye of Ørsta, Norway; from Tamás Ábrahám of Zsámbék, Hungary; from Stefano De Rosa of Turin, Italy;

SOLAR TRANSIT: Yesterday, amateur astronomer Lars Zielke was photographing sunspot 1035 using a solar telescope at his backyard observatory in Tvis, Denmark. Everything was going fine when suddenly a shadowy black form transited the field of view:

"Normally these kinds of black spots are caused by birds or bugs," he says. "But today I found something very interesting. Please see the movie where I have slowed down the speed to 4 frames per second from the original 60 fps."

Mystery solved. Merry Christmas!

more sunspot photos: from Rogerio Marcon of Campinas - Brasil; from John C McConnell of Maghaberry, Northern Ireland; from Pete Lawrence of Selsey, West Sussex, UK; from Jimmy Eubanks of Boiling Springs, SC; from Steve Riegel of Santa Maria, CA; from Cai-Uso Wohler of Bispingen, Germany; from Peter Paice of Belfast, Northern Ireland;

2009 Geminid Meteor Gallery
[sky map] [meteor radar] [Geminid counts]

December Northern Lights Gallery
[previous Decembers: 2008, 2007, 2006, 2005, 2001, 2000]

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 December 20, 2009 there were 1090 potentially hazardous asteroids.

Dec. 2009 Earth-asteroid encounters:

Asteroid	Date(UT)	Miss Distance	Mag.	Size
2009 WV25	Dec. 1	2.9 LD	16	65 m
2009 WA52	Dec. 5	8.2 LD	20	23 m
2002 WP	Dec. 6	71.2 LD	16	950 m

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.