beachton123 wrote:Solar Dynamics Observatory Launch, Feb 11, 2010 HD VERSION A sun dog is a prismatic bright spot in the sky caused by sun shining through ice crystals. The Atlas V rocket exceeded the speed of sound in this layer of ice crystals, making the shock wave visible from the ground. The announcer can be heard in the video saying, "The vehicle is now supersonic."
It seems reasonable to me. I don't think it's spherical, though. The shock wave behind the rocket should be conical. From a single rear viewpoint, it would be hard to tell the difference.RJN wrote:Is the spherical shock really caused by the sonic boom? Anyone have a feeling for this?
My thinking is that the path of the rocket is through a fairly thin cloud layer, and substantially perpendicular to that layer. So regardless of viewpoint, what we are seeing is the intersection of a horizontal plane (the cloud layer) with a cone. Because the rocket is moving upwards, with its shock cone trailing, the shock appears as a circle of increasing diameter.RJN wrote:Thanks, Chris! I played the movie several times trying to see if the shock front projections appeared (2D) circular or parabolic. It is hard to tell, but the top part appears somewhat circular. I would expect a conical shock wave to appear parabolic from off to the side, as the projection of a cone onto a vertical plane is a parabola. Any thoughts on that?
SDO is designed to amaze — and it got off to a good start.
Videos by Anna Herbst, Romeo Durscher, and Barbara Tomlinson.
