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SUPER PROMINENCE:
"Wow - what a sight greeted me this
morning as I set up my H-alpha telescope," reports Pete Lawrence
of Selsey, UK. "There was a huge plume of plasma on the northwestern
limb of the sun: photo.
If you've got a solar
telescope, take a look, it's changing but still visible."
more images: from
SOHO; from
Dalouzy Jean-Christophe of Caen, Normandy, France; from
Stephen Ames of Hodgenville, Kentucky; from
Lecoq Etienne of Mesnil-Panneville, Normandy, France;
FIRST NLCs of 2009:
New data from NASA's AIM spacecraft show
that noctilucent
clouds (NLCs) are like a great "geophysical light bulb."
They turn
on every year in late spring, reaching almost full intensity
over a period of no more than 5 to 10 days.
News flash: The bulb is beginning to glow. The first NLCs of 2009
were sighted over Russia on May 27th, and an even brighter display
appeared on May 29th over Denmark and the British Isles. Martin
Mc Kenna sends these snapshots from Maghera, Northern Ireland:
"The glowing clouds were more than 100 degrees wide with white,
blue and even subtle yellow and green colours," says Mc Kenna.
"It was an excellent display to start the season and a good
omen of major events to come in the near future!"
The May 29th display was also witnessed by John C Mcconnell of
Maghaberry Northern Ireland (photos);
Paul Evans of Larne, Northern Ireland (photos);
and Ian Brantingham near Banff, Scotland (photos).
There is a well-known correlation
between noctilucent clouds and the solar cycle. NLC activity tends
to peak during years of solar minimum, possibly because low solar
activity allows the upper atmosphere to cool, promoting the growth
of ice crystals that make up the clouds. With a century-class
solar minimum underway, the stage is set for a good season of
NLC watching.
Typically, the first NLCs of spring are wan and pale, followed
by better displays as summer unfolds. Browse the galleries from
previous years to see what may be in the offing: 2008,
2007, 2006,
2005, 2004,
2003.
LIGHTNING SPLASH:
On May 26th, photographers Francis Schaefers
and Daniel Burger were chasing a thunderstorm along a beach in Vlissingen,
the Netherlands, when "the storm turned around and came a little
too close for comfort," says Schaefers. "We were able
to photograph lightning hitting the water just 40 meters away."
Here is the view through their Canon
400D:
Look closely where the lightning meets the water. Tiny bolts appear
to be dancing around the impact site.
"Those are called 'upward streamers,'" says lightning
expert Richard Blakeslee of the NASA Marshall Space Flight Center.
"In a typical cloud-to-ground lightning strike, as the leader
approaches the ground, the large electric field at the leader tip
induces these upward propagating streamers. The first one that connects
to the downward propagating leader initiates the bright return stroke
that we see with our eye. Upward streamers are often observed on
photographs of lightning hitting the ground."
Now we know they can be seen when lightning hits the water, too.
Schaefers and Burger took many pictures that night, mostly from
underneath a balcony where they figured the lightning wouldn't reach.
This favorite is
called The Cruise You Don't Want to Take.
April
2009 Aurora Gallery
[previous Aprils: 2008,
2007, 2006,
2005, 2004,
2003, 2002]
Explore
the Sunspot Cycle
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