Listen to radar echoes from satellites and meteors, live on listener-supported Space Weather Radio. |
|
|
GEOMAGNETIC STORM
WARNING: NOAA forecasters estimate
a 75% chance of polar geomagnetic storms today.
The warning is prompted by a CME, which is expected
to hit Earth's magnetic field on May 19th. High-latitude
sky watchers should be alert for auroras when the
cloud arrives. Aurora
alerts: text,
voice.
The Solar and Heliospheric Observatory
took this picture of the CME leaving the sun at
1500 km/s (3.4 million mph) on May 17th:
It was hurled into space by an M3-class
solar flare in the magnetic canopy of sunspot AR1748.
In the
video, the CME appears to hit Mercury, but it
does not. It is merely passing in front of the innermost
planet. The planet in the line of fire is Earth.
Realtime
Space Weather Photo Gallery
AURORAS INVADE THE USA: A CME hit
Earth's magnetic field on May 18th at around 0100
UT. Although it was just a glancing blow, the impact
was enough to spark a G1-class geomagnetic storm.
In the United States, Northern Lights descended
as far south as Pawnee Buttes, Colorado:
"The aurora was not visible to
the naked eye," says photographer Robert Arn.
"Only with a 30 second exposure did I know
it was there. As I started to collect data, I noticed
an electrical storm in the distance. The juxtaposition
of the electrical storm and aurora made for a spectacular
image. (The moon near the horizon illuminated the
landscape.)"
Elsewhere in the United States, faint
auroras were photographed in Michigan, Massachusetts,
Washington, Vermont, and Iowa. Browse the aurora
gallery for more sightings.
Realtime
Aurora Photo Gallery
DISCONNECTION EVENT
IN THE TAIL OF COMET LEMMON: Comet
Lemmon (C/2012 F6), which is receding from the sun
not far beyond the orbit of Earth, has just experienced
a "disconnection event." A cloud of dusty
plasma is propagating down the comet's tail, shown
here in a photo taken by Paul Mortfield on May 15th:
"I was pretty surprised to see
this disconnection event when I processed the images,"
says Mortfield. "The comet is a challenge to
photograph because it is so low in the sky at the
start of morning twilight."
Disconnection events can be caused
by CME impacts. A famous example is that of Comet
Encke in 2007. Comet Lemmon, however, is not
on the same side of the sun as active sunspot AR1748.
It's hard to see how the recent X-flares can be
responsible. Nevertheless, solar activity is high,
so now is a good time to monitor comet tails. They
are very sensitive to stormy space weather.
Comet Lemmon is a pre-dawn object
for observers in the northern hemisphere. It is
currently gliding alongside the Great Square of
Pegasus in the eastern sky before sunrise. The 7th-magnitude
comet is too faint to see with the naked eye, but
it is visible in medium-to-large backyard telescopes.
Observers with computerized GOTO 'scopes should
point their optics here.
More about Comet Lemmon:
3D
orbit, ephemeris,
light
curves.
Realtime
Comet Photo Gallery
Realtime
Aurora Photo Gallery
Realtime
Noctilucent Cloud Photo Gallery
[previous years: 2003,
2004,
2005,
2006,
2007,
2008,
2009,
2011]
