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NEW SUNSPOT:
Observers are reporting a new sunspot forming near the sun's southeastern
limb. It appears to be a member of Solar Cycle 24. images:
#1,
#2.
VOLCANIC SUNSETS:
People across the USA (and now parts of
Europe) are reporting unusual sunsets. When the sun goes down, delicate
ripples
of white appear over the western horizon. Then, as the twilight
deepens, the sky turns a telltale shade of "volcanic lavender."
Steven Hallgren photographed this example last night, June 29th,
from of Coeur d'Alene, Idaho:
"With all the talk of volcanic sunsets, I had to take a look
for myself," says Hallgren. "The purple was out in full
force."
The source of the phenomenon is Russia's Sarychev
Peak volcano. It erupted on June 12th, hurling massive plumes
of sulfur dioxide (SO2) and other debris into the stratosphere.
The white ripples that herald these sunsets are made of volcanic
aerosols--a mixture of ash and sulfur compounds. Blue light scattered
by fine volcanic aerosols combines with ordinary red sunset rays
to produce the telltale lavender.
Earth-orbiting satellites are monitoring Sarychev's sulfur
dioxide plume as it circumnavigates the globe at high latitudes,
spreading the phenomenon from Russia to the USA to Europe and back
again. All northern sky watchers should be alert for volcanic sunsets.
UPDATED: 2009
Sarychev Sunset Gallery
[See also: 2008
Kasatochi Sunset Photo Gallery]
TAPETUM LUCIDUM:
Robert Smith of Stoneville, North Carolina,
went outside last night to look for volcanic sunset colors. "I
fired my flash at the landscape," he says, "and there
were two bright eyes staring back at me!" It was a fox:
"Just look at those reflections," he says.
The eyes of foxes reflect light using an organic mirror called
the tapetum
lucidum. The tapetum is a layer of shiny tissue at the back
of the retina. It increases the sensitivity of the eye. Photoreceptors
get two chances to "see the light"--once on the way in
and once again on the way back out. Creatures that hunt at night
usually have a tapetum; creatures that sleep at night (e.g., humans)
usually do not.
Astronomers really wish they had one! At least we can see
the fox.
2009
Noctilucent Photo Gallery
[previous years: 2008,
2007, 2006,
2005, 2004,
2003]
Explore
the Sunspot Cycle
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