NEW AND IMPROVED:
Turn your iPhone or iPod Touch into a field-tested
global satellite tracker. The Satellite
Flybys app now works in all countries. |
|
|
THE MYSTERY OF PHOBOS:
Something is wrong with Phobos.
The martian moon looks like a solid, but it is not as dense
as a rocky solid should be. Some researchers think Phobos
might be riddled with vast caverns; others say it is just
a "rubble pile" masquerading as a solid body. To
solve the
mystery, Europe's Mars Express spacecraft is making a
series of close Phobos-flybys this month. March
10th update: According to gravity-field data
just beamed back from Mars Express, mass is not evenly
distributed throughout the moon’s interior. A detailed analysis
is underway by ESA researchers. Stay
tuned!
IDITAROD SKIES: This
week, hundreds of the world's finest athletes are racing 1,150+
miles across some of most extreme and beautiful terrain in
the world--the Iditarod trail of Alaska. If any of those
sled dogs raise their blue eyes to the sky, they might
see something like this:
Daryl Peterson took the picture on March 21,
2009. "I went to Nome last year to shoot the finish of
the Iditarod," he recalls. "During the race you
can almost bank on seeing some Northern Lights, even when
solar activity is low."
He's right. On average, March is the most geomagnetically
active month of the year; October is a close second (histogram).
The reason is not fully understood, but it has something to
do with the orientation of Earth's axes and the sun's magnetic
field around the time of the equinoxes. The Iditarod takes
place smack-dog in the middle of aurora
season.
Now, if only huskies could operate a camera....
March
Northern Lights Gallery
[previous Marches: 2009,
2008, 2007,
2006, 2005,
2004, 2003]
SOLAR
TRANSIT: The sun is blank--no sunspots. That
makes it much easier to pick out the spaceships. On March
7th, Leonardo Julio of Buenos Aires, Argentina, watched the
silhouette of the International Space Station zip across the
featureless solar disk:
Click
to view the full solar disk
"The ISS crossed the entire solar disk
in only 0.5 seconds," says Julio. "I captured the
split-second transit using a solar-filtered Meade LX-90 8-inch
telescope and a Canon EOS 40D digital camera (1/1600 sec,
ISO-1600)."
The ISS is easier to see in the night sky where
the glare of the sun is absent and the super-bright spaceship
spends a leisurely five minutes gliding from horizon to horizon.
Check the Simple Satellite Tracker for
flybys of your home town. And don't forget, there's
an app for that, too.
more ISS images: from
Pawel Warchal of Krakow, Poland; from
Jo Smeets of Maastricht Netherlands; from
Max Bittle of Concord, New Hampshire
|
