Quadrantid Meteors (APOD 07 Jan 2008)

[iamlucky13]

First of all, can anybody explain what this means?

Preliminary indications are that the meteor stream is quite stable in time but variable in meteor abundance.

My reading of it is the rate is constant but constant? From the link, I'm guessing they meant to suggest the rate vs. time graph was roughly normal (Gaussian).

Second, the caption (and in fact the NASA press release) incorrectly states that the tail of NASA-Dryden's DC-8 is visible in the picture. In fact, the observations were conducted from a Gulfstream V business jet on loan from Google, not NASA's DC-8, which I don't believe had the range needed. Additionally, that is not the tail, but the angled up winglet on the very end of the wing. The above link also has a photo of this aircraft.

http://antwrp.gsfc.nasa.gov/apod/ap080107.html

[orin stepanek]

First of all, can anybody explain what this means?

Preliminary indications are that the meteor stream is quite stable in time but variable in meteor abundance.

My reading of it is the rate is constant but constant? From the link, I'm guessing they meant to suggest the rate vs. time graph was roughly normal (Gaussian).

Second, the caption (and in fact the NASA press release) incorrectly states that the tail of NASA-Dryden's DC-8 is visible in the picture. In fact, the observations were conducted from a Gulfstream V business jet on loan from Google, not NASA's DC-8, which I don't believe had the range needed. Additionally, that is not the tail, but the angled up winglet on the very end of the wing. The above link also has a photo of this aircraft.

http://antwrp.gsfc.nasa.gov/apod/ap080107.html

I read through some of the link [preliminary indications] and it says that the photo was indeed taken above the wing of the aircraft; so your observation is correct about the wing. Also; there is a photo of the aircraft on takeoff that shows the wing tip quite clearly.
Orin

[iamlucky13]

Yeah, the second part wasn't really a question, just an observation.

I'm still kind of curious if anybody has a good idea what the author was trying to say with that quote.

[Chris Peterson]

First of all, can anybody explain what this means?

Preliminary indications are that the meteor stream is quite stable in time but variable in meteor abundance.

Here's my interpretation: meteor streams vary in the stability of their orbits. That is, some streams are more influenced by gravitational perturbations than others. Also, some streams are more like a single stream, while others consist of many individual strands. The Quadrantid debris stream appears to be stable in time, meaning we encounter it in a very predictable way from year to year. That is quite different from the issue of how homogeneous the debris is along the orbit. In this case, material is clumped unevenly, so depending on what part of the orbit crosses the Earth's path, you may have just a few meteors or very strong activity.

Put slightly differently, the orbit is very stable, but the debris distribution is variable.