When NASA launched its Solar Dynamics Observatory into orbit on an ATLAS V rocket in February 2010, it went off without a hitch.
But the launch left many onlookers puzzled by a phenomenon that's rarely seen at rocket launches. At one point, just seconds after launch, the rocket seemed to produce enormous shockwaves that destroyed a nearby sundog, an icy replication of the sun's rays.
Because the rocket wasn't moving at supersonic speeds, they couldn't have been a sign of the craft breaking the sound barrier. However, Millersville undergraduate meteorology major Adam Jacobs may have provided the best explanation to date. His research was even good enough to be featured on NASA's SDO website.
Jacobs suggests that the waves weren't caused by the rocket breaking the sound barrier but rather by the air around the rocket creating Mach waves. Mach waves, which according to the presentation seem the most likely candidate, are essentially little pockets of air moving at supersonic speeds relative to the air around them.
But since Mach waves aren't always necessarily visible, Jacobs suggested these were made visible by sudden changes in density and orientation of the sundog's ice crystals as they were hit by the waves. It's like adjusting the angles of millions of tiny panes of glass in mid-air.
For the scientifically inclined, Jacobs' full presentation is available online.
While the explanation seems simple enough, the motion is a far from normal occurrence, hence the millions of views garnered by the YouTube video.
WATCH (The Waves):
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