Cool Movie: SDO Destroys a Sundog (w/ Video)

Feb 19, 2010 by Dr. Tony Phillips
Sundogs are formed by the refracting action of plate-shaped ice crystals. Image credit: Les Cowley/Atmospheric Optics

Last week, on Feb. 11th, the Solar Dynamics Observatory (SDO) lifted off from Cape Canaveral on a five-year mission to study the sun. Researchers have called the advanced spacecraft the "crown jewel" of NASA's heliophysics fleet. SDO will beam back IMAX-quality images of solar explosions and peer beneath the stellar surface to see the sun's magnetic dynamo in action.

SDO is designed to amaze—and it got off to a good start.

"The observatory did something amazing before it even left the atmosphere," says SDO project scientist Dean Pesnell of the Goddard Space Flight Center.

Moments after launch, SDO's Atlas V rocket flew past a sundog hanging suspended in the blue Florida sky and, with a rippling flurry of , destroyed it. Click 'Play' below to launch a video recorded by 13-year-old Anna Herbst at NASA's Banana River viewing site—and don't forget to turn up the volume to hear the reaction of the crowd.

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SDO has a close encounter with a sundog. Credit: Anna Herbst of Bishop, California.

"I couldn't believe my eyes," says Anna. "The shock waves were so cool." Anna traveled with classmate Amelia Phillips three thousand miles from Bishop, California, to witness the launch. "I'm so glad we came," says Amelia. "I've never seen anything like it!"

Sundogs are formed by plate-shaped ice crystals in high, cold cirrus clouds. As the crystals drift down from the sky like leaves fluttering from trees, aerodynamic forces tend to align their broad faces parallel to the ground. When sunlight hits a patch of well-aligned crystals at just the right distance from the sun, voila!--a sundog.

"When the Atlas V rocket penetrated the cirrus, shock waves rippled through the cloud and destroyed the alignment of the crystals," explains atmospheric optics expert Les Cowley. "This extinguished the sundog."

Videos by other photographers at Banana River show the shock waves particularly well. Here's one from Romeo Durscher of Stanford, California:

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And another from Barbara Tomlinson of Beachton, Georgia:

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In the past, says Cowley, there have been anecdotal reports of atmospheric disturbances destroying sundogs—for instance, "gunfire and meteor shock waves have been invoked to explain their disruption. But this is the first video I know of that shows the effect in action."

The effect on the crowd was electric.

"When the sundog disappeared, we started screaming and jumping up and down," says Pesnell. "SDO hit a home run: Perfect launch, rippling waves, and a disappearing sundog. You couldn't ask for a better start for a mission."

SDO is now in orbit. "The observatory is doing great as the post-launch checkout continues," he reports. "We'll spend much of the first month moving into our final orbit and then we'll turn on the instruments. The first jaw-dropping images should be available sometime in April."

Believe it or not, Pesnell says, the best is yet to come.

Explore further: Computer model shows moon's core surrounded by liquid and it's caused by Earth's gravity

Source: Science@NASA, by Dr. Tony Phillips

4.7 /5 (6 votes)

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User comments : 3

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Husky
1 / 5 (1) Feb 19, 2010
Perhaps, the launch of the observatory could confirm whether there is indeed a pot of gold at the end of a rainbow or sundogs tail, but the real gold would be in the rich data and increased understanding of magnetohydrodynamic processes governing our sun and other stars. Increasingly the mainstream astronomy community becomes aware that magnetism plays a much more defining role in the birth, life and death of stars and even galaxies. Some see this as the return of the electric universe or support for plasma cosmology, wich due to its attraction for aether concept adepts, was kind of banned completely by prevailing standard model cosmologists, in effect completely throwing relevant plasma away with the supposed aether crackpots trumpetting plasma as a visible analogue/derivate of the supposed invisible aether medium, only now to discover that the truth lies in the middle, neither the standard model nor plasma model is one size fits all.
Hungry4info2
1 / 5 (1) Feb 20, 2010
The understanding of magnetic fields in astronomy is not new, nor is it some sort of middle ground between real science and fantasy.
yyz
not rated yet Feb 20, 2010
This extraordinary event witnessed by thousands of observers at the cape was thoroughly explained by Dr. Phil Plait and others as a natural phenomenon and poster #4) IVAN3MAN provided links to other sites that had simultaneous video of the same event. Even some NASA cameras caught this event. NO EU-PU woo is necessary to describe this beautiful manifestation of a well-understood aspect of an atmospheric phenomenon! :)

The link is at: http://blogs.disc...the-sky/