Metallic photos of the sun by renowned photographer Greg Piepol bring together the best of art and science. Buy one or a whole set. They make a stellar gift. |
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VENUS-DIRECTED
CME: A coronal mass ejection (CME,
movie)
that swept past Mercury on Nov. 13th will likely
hit Venus later today. Because Venus has no global
magnetic field to protect it, the impact could erode
material directly from the top of the planet's atmosphere.
It's okay; Venus has atmosphere to spare. Analysts
at the Goddard Space Weather Lab calculated the
path of the CME, which left the sun on Nov.
12th.
REMARKABLE
SOLAR ACTIVITY: In terms of solar
flares, the sun is quiet today. Nevertheless, some
impressive activity is underway on the sun. For
one thing, an enormous wall of plasma is towering
over the sun's southeastern horizon. Stephen Ramsden
of Atlanta, Georgia, took this picture on Nov. 11th:
"Solar forums all over the world
are buzzing with Sun-stronomers proclaiming this
to be the biggest prominence that many of them had
ever witnessed," he says.
Remarkably, though, this is not the
biggest thing. A dark filament of magnetism is winding
halfway around the entire sun. NASA's Solar Dynamics
Observatory took this picture during the early hours
of Nov. 14th:
From end to end, this twisted fiber
of magnetism stretches more than a million km or
about three times the distance between Earth and
the Moon. If the filament becomes unstable, as solar
filaments are prone to do, it could collapse and
hit the stellar surface below, triggering a Hyder
flare. No one can say if the eruption of such
a sprawling structure would be Earth directed. Solar
flare alerts: text,
phone
"I cant help but wonder what
could possibly come next since we are still over
a year away from the forecasted Solar Maximum,"
adds Ramsden. "There's never been a better
time to own a solar
telescope than now!"
SOLAR
UPDATE: The wall of plasma on the
sun's SE limb has shifted to a state of high activity.
"The prominence is evolving very fast now!"
reports Sylvain Weiller of Saint Rémy lès Chevreuse,
France. This
morning it looked like [the dinosaur] Diplodocus."
more images: from
Pete Lawrence of Selsey, West Sussex, UK; from
Kamil Kusinski of Wloszczowa, Poland; from
Christoph Otawa of Geretsried, Bavaria, Germany;
from
Wouter Verhesen of Sittard, the Netherlands;
from
Roel Weijenberg of Wilp, The Netherlands; from
Michael Borman of Evansville, Indiana; from
Jesus Muñoz of Querétaro, México; from
Alan Friedman of Buffalo, NY; from
Theo Ramakers of Social Circle, GA; from
John Stetson of Falmouth, Maine; from
Randy Shivak of Elyria, OH; from
Steve Riegel of Albuquerque, NM; from
Robert Arnold of Ilse of Skye, Scotland;
DISAPPEARING
TRICK: If you're a spy satellite,
the ability to disappear could come in handy. US
spysat Lacrosse
5 occasionally performs just such a trick. On
Nov. 11th, satellite watcher Dr. Marco Langbroek
of Leiden, the Netherlands, caught the orbiting
radar suddenly fading to near invisibility:
"Lacrosse 5 is typically bright
but occasionally performs what is known among observers
as the 'disappearance trick,'" says Langbroek.
"Its brightness suddenly drops 3 astronomonical
magnitudes or more."
Could this be a deliberate form of
stealth? Langbroek doesn't think so. "Maybe
some part of the spacecraft such as its solar panels
casts a shadow over the main body," he speculates.
"Or perhaps the surface of Lacrosse 5 becomes
less reflective at certain viewing angles. This
could happen as the craft suddenly changes attitude
for some reason." Other Lacrosse satellites
do not perform the trick, at least not to this extent,
suggesting that the design of Lacrosse 5 differs
from its predecessors.
"Later in the movie a bright
Soyuz rocket booster (81-008B) passes by as well,"
he adds. "This is a piece of space debris connected
to the 1981 launch of a Russian military satellite."
Readers, would you like to try catching
the tricks of Lacrosse 5? Local flyby times may
be found on the web or on
your smartphone.
