You are viewing the page for Mar. 20, 2009
  Select another date:
<<back forward>> -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
Current conditions
Solar wind
speed: 418.3 km/sec
density: 1.5 protons/cm3
explanation | more data
Updated: Today at 2346 UT
X-ray Solar Flares
6-hr max: A0
2340 UT Mar20
24-hr: A0
2340 UT Mar20
explanation | more data
Updated: Today at: 2340 UT
Daily Sun: 20 Mar 09
The sun is blank--no sunspots. Credit: SOHO/MDI
Sunspot number: 0
What is the sunspot number?
Updated 18 Mar. 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= 2
explanation | more data
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
What is the auroral oval?
Interplanetary Mag. Field
Btotal: 9.5 nT
Bz: 9.3 nT north
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 March 20th. Credit: SOHO Extreme UV Telescope
NOAA Forecasts
Updated at: 2009 Mar 20 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 Mar 20 2201 UTC
0-24 hr
24-48 hr
05 %
05 %
01 %
01 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
10 %
10 %
01 %
01 %
01 %
01 %
What's up in Space
March 20, 2009

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


AURORA SPRING: The first day of northern Spring could end with a display of Northern Lights. A solar wind stream is expected to hit Earth on March 20th, and the impact could trigger geomagnetic activity around the Arctic Circle. High-latitude sky watchers should be alert for auroras: gallery.

NEAR THE EDGE OF THE SUN: Imagine looking up at noon and seeing a planet with four moons just 0.1o from the edge of the blinding sun. Impossible? NASA's STEREO-B spacecraft did it this week. Click on the image below to launch a movie of Jupiter and the Galilean satellites in close "solar conjunction."

5 MB Quicktime movie | labeled still frame | Zoom in on Jupiter

During the 30-hour movie, Io, Europa, Ganymede and Callisto circle Jupiter as a massive CME billows overhead. STEREO-B recorded the action on March 15th and 16th using an occulting disk to block the solar glare. This arrangment allowed STEREO's cameras to photograph moons of Jupiter eight thousand billion (8x1012) times dimmer than the adjacent sun.

STEREO's coronagraph (occulting disk+camera) is designed to monitor faint but powerful activity in the sun's outer atmosphere. The CME is a good example. With a limiting magnitude of +6.5, it can also see stars, planets, moons and comets so close to the edge of the sun, it seems impossible. In fact, it happens all the time. Browse the STEREO gallery for examples.

GREAT HALOS: On March 18th, a bank of icy cirrus clouds drifted over Strasbourg, France. At first, it looked like just another cloudy day--ho, hum. And then the halos appeared. "There was an amazing outburst of colorful arcs and rings around the sun," says onlooker Herfried Eisler. The display was so big, he had to use a fisheye lens to catch it all:

He also created a horizontal 360o panorama; it is a must see.

Eisler marveled at the diversity: "I saw a 22° halo, a pair of sundogs, a cirumscribed halo, a parry arc, a parhelic circle, upper and lower tangent arcs, infra- and superlateral arcs, a 180° anthelion, some bright 46° arc fragments, faint 120° parhelions, and two rare Wegeners anthelic arcs."

According to atmospheric optics expert Les Cowley, "this wonderful variety of halos was created by sunlight shining through one basic type of ice crystal--the hexagonal ice prism." Hexagonal ice prisms can take the form of short, fat plates or long, thin columns; when these forms are aligned in no more than five different ways, they can account for all of the things Eisler saw.

The clouds that made the French halos on March 18th were also present over other parts of Europe. Click on the links for more images: from Eva Seidenfaden of Trier, Germany; from Andreas Walker of Hallwil, Switzerland; from Herfried Eisler of Strasbourg, France; from Yvette Cendes of Kitzbuhel, Austria

March 2009 Aurora Gallery
[previous Marches: 2008, 2007, 2006, 2005, 2004, 2003, 2002]

Comet Lulin Photo Gallery
[Comet Hunter Telescope: review] [Comet Lulin finder chart]

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 March 20, 2009 there were 1043 potentially hazardous asteroids.
March 2009 Earth-asteroid encounters:
Miss Distance
2009 DS43
Mar. 1
6.9 LD
32 m
2009 DD45
Mar. 2
0.2 LD
35 m
2009 DN4
Mar. 3
8.1 LD
27 m
2009 EA
Mar. 4
7.4 LD
24 m
2009 EW
Mar. 6
0.9 LD
23 m
161989 Cacus
Mar. 7
70.5 LD
1.7 km
2009 EH1
Mar. 8
1.6 LD
12 m
2009 ET
Mar. 9
9.5 LD
15 m
2009 DV43
Mar. 10
8.5 LD
80 m
2009 EU
Mar. 11
3.5 LD
21 m
1998 OR2
Mar. 12
69.8 LD
3.3 km
2009 DR3
Mar. 14
7.2 LD
225 m
2009 FH
Mar. 18
0.2 LD
21 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.
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.