A while ago I got to see local TV news show video of the Proton re-entry yesterday. I don't know if they were playing the film in slow motion, or if it was really that slow. Also, in this video, there appeared to be two parallel and quite separate tracks, both of them large and fragmenting. I'm puzzling over some of the re-entry reports and want to pose a question that I'm definitely not qualified to answer. Here's a sample from about 32 km south of Lincoln, Nebraska, USA, that was forwarded to the Meteorobs list by Gary Kronk: > Starting at the SW horizon we followed with our eyes no less > than 50 "shooting stars" streaking across the sky above us > to the NE horizon where the earths' curvature prevented > further observation of light show. Estimated total time of > sighting from our position was 20-30 seconds. I am trying to figure out how a track from SW horizon to NE horizon could only last 20-30 seconds. Taking it a different way, if the fiery objects were at the expected height for the observing site, how high above the ground would they have been, and how long would it have taken them to traverse the sky from horizon to horizon? Another question is at what height above the ground would we expect such objects to slow down enough to stop being visible? I'm wondering if a very low height could be consistent with a fast traverse, but doubting that objects that low would still be visible. I haven't seen any reports of sonic booms. For reference, the Space Shuttle takes something like two minutes to cross from horizon to horizon on a re-entry that's above 30 degrees above the horizon. I believe at that time that it's something like 80 km up, when it's due north or south of us here. (Or maybe the range is 80-90 km.) One correction to an earlier post. I wrote that I had seen a report of "east to west" direction on the re-entry over England-France-Belgium, but it was west to east, from an observer in England. Ed Cannon - ecannon@mail.utexas.edu - Austin, Texas, USA ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www.satellite.eu.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Mon Dec 03 2001 - 00:58:03 EST