Treebeard's Stumper 27 September 2002

National Defence Light Show

Do'h, I missed that spectacular Vandenberg AFB missile launch last week. I've seen other twilight Minuteman launches so I know what I missed, and I have photos here to prove it. The low part of the missile contrail is reddish and twisted like a corkscrew. The high part is bright white. There are expanding rainbow colors at the very top. We only see this light show at twilight. How does this work? Sometimes the sky over school is full of commercial jet trails, but this week the sky has been clear. What do these contrails depend on?

LA Times photo by Gary Friedman showing the Sep. 19, 2002 Minuteman III launch from Vandenberg AFB.	My friend Mike Davidson sent this photo of the same launch taken some time later in Paradise. .
I took this photo of a different Minuteman missile launch on Oct. 2, 1999, from my porch on San Marcos Pass.	Beautiful photo by Hayne Palmour of a June 23, 1997 launch, taken in Vista near San Diego. .

There are many more missile launch photos at Fred's Astronomy Stuff, SoCal Sky Lights, Art Bell, and The Goleta Air and Space Museum. John Parres has a nice sequence of photos of the Sep. 19 launch.

These photos of different missile launches over the years have a lot in common:

• They are all Minuteman II and III missiles launched from Vandenberg AFB in California.
• The spectacular light show colors only happen at twilight.
• The light show is visible across the west, as far away as Las Vegas, Sacramento, and beyond.
• The launches always generate concern about national security and UFOs, e.g. Art Bell and Area 51.
• The dynamics are better than any photograph can show.
• The missile contrail is not visible all the way to the ground.
• The lower part is reddish or orange, and dimmer than the top.
• The upper part is bright white.
• There are expanding rainbow colors at the very top.
• The contrail is twisted like a corkscrew, and the spirals grow over time.
• The contrail stays together for a long time, 1/2 hour or longer until after dark.

I wanted to shoot a photo of commercial jet contrails for this stumper. The sky is usually full of them here under the flight path between LA and SF, but this week the sky was clear. It's also been an odd weather week. It was 105° at school on Tuesday, but now we have cool temperatures and real rain on Saturday. Sometimes I see commercial jet contrails go on and off in the sky, as though the pilot has a "smoke switch" like a sky-writer. Sometimes I see dark "shadow trails" behind the jets instead of the usual white cloud-like trails. How do all these contrails work?

This stumper is about missile launches, and by sheer coincidence, NASA this week will show us what a rocket launch looks like from the rocket! Nasa filmed the Space Shuttle Atlantis launch on Monday, October 7, from a camera attached to the external fuel tank. You can find the video at the sts-112 Video Index.

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