What created those rocket waves, and why did they destroy that sun dog? Close inspection of the
above image shows not only a rocket rising near the center, but unusual air ripples around it and a colorful sundog to the far right. The rocket, carrying the
Solar Dynamics Observatory (SDO), lifted off two weeks ago from
Cape Canaveral,
Florida,
USA into a cold blue sky. The
SDO is designed to observe the Sun continuously over the next several years, exploring the Sun's atmosphere at high resolution and fast time scales. The air ripples -- seen about one minute after launch -- were unexpected, as was the sudden disappearance of the sundog after the ripples passed.
Noticed and
recorded by
several onlookers, there has been much speculation about the origin of
the ripples. An ongoing discussion about them can be joined
here in APOD's discussion board
the Asterisk. A leading hypothesis holds that the ripples resulted from a
sonic boom created as the rocket broke the sound barrier, which then jumbled a thin layer of
ice crystals that were aligned to create the
sundog. Lingering
questions include why other rocket launches don't produce air ripples as noticeable, and why the ripples appeared more prominent above the rocket. If you know of images of any other
aircraft or spacecraft that have produced similar air ripples, please post them to
the discussion thread -- they may be help create a better understanding of the effect.