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SOLAR WIND RIPS MARS:
The solar wind appears to be ripping big
chunks of air from the atmosphere of Mars. This could help solve
a longstanding mystery about the Red Planet: full
story.
SASKATCHEWAN FIREBALL:
A brilliant green fireball startled onlookers
across western Canada on Nov. 20th (5:30 pm MST) when it split the
evening sky and fragmented during a series of thunderous explosions.
"The sky was lit up almost like daytime for 3 or 4 seconds,"
reports Gordon Blomgren of Alberta. Murray McDonnell of northwestern
Saskatchewan says "my wife and I saw a brilliant flash of blue
white light, like lightning. About one minute later a long rumbling
sound shook the house."
Andy Bartlett video-recorded the event from a 10th-floor apartment
in Edmonton, Alberta:
Click to
play the video
"The brilliant fireball appeared to be closer than the airplane
in the upper right corner of this video," says Bartlett. "I
made the movie using a Canon
A510."
The fireball was almost certainly a small asteroid disintegrating
in Earth's atmosphere. A space rock measuring a few to ten meters
wide moving at typical local-asteroid velocities would account for
the fireball's speed and brightness. Reentry of manmade space junk
has now been ruled out. Fragments of the impactor may have reached
the ground; if so, they remain undiscovered and/or unreported.
VIDEO UPDATE: A spectacular
video of the fireball was recorded by the dashboard camera of a
police car on patrol in Edmonton, Alberta. Click
to play.
FALSE AURORAS:
Warning: Not all northern lights are aurora borealis. Consider the
following display of "false auroras" over Ambler, Pennsylvania,
on Nov 19th:
Photo details: Nikon
D200, ISO 1600, f5, 10s exposure
"Luminous vertical spikes emanated down from all areas of
the sky," reports photographer Herman
Fala. "They looked like Northern Lights, but did not seem
to be moving or shimmering as I expected auroras to do." Furthermore,
solar activity was low and no geomagnetic storm was in progress
at the time of the display.
What Fala witnessed was an apparition of urban
light pillars. Plate-shaped ice crystals flutter down from high
clouds and intercept the rays of unshielded city lights, creating
an aurora-like display that truly has nothing to do with auroras.
Light pillars are beautiful but they are also a sign of spreading
light pollution that threatens to wipe genuine auroras (and stars
and planets and comets) out of the night sky forever. Enjoy them,
but also be mindful of their dark
significance.
High-latitude sky watchers should be
alert for real auroras
next week. A solar wind stream is heading for Earth and it could
spark geomagnetic storms when it arrives on Nov. 24th or 25th.
UPDATED: Nov.
2008 Aurora Gallery
[Previous Novembers: 2007,
2006, 2004,
2003, 2001,
2000]
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