On Fri, 13 Feb 2009 11:33:05 -0800 (PST), wrote:

On Feb 13, 12:03*pm, Cliff wrote:
[
READ BELOW BEFORE WATCHING VIDEO * * * * * * * * * * * * * * * * * * * * *

Now here is a fascinating one-minute video... * * * * * * * * * * * * * * *
It is a 24-hour observation of all of the large * * * * * * * * * * * * * *
aircraft flights in the world (recorded by the airplane * * * * * * * * * *
flight transponders via Geo-stationary orbital satellites) * * * * * * * *
patched together and condensed down to about a minute, i.e., * * * * * * *
you watch 24 hours of flights compressed into one minute. * * * * * * * * *

From space we look like a beehive of activity. * * * * * * * * * * * * * *
You can tell it is summer time in the north by the * * * * * * * * * * * *
sun's footprint over the planet. You can see that * * * * * * * * * * * * *
it doesn't quite set in the extreme north and it * * * * * * * * * * * * *
doesn't quite rise in the extreme south. We are taught * * * * * * * * * *
about the earth's tilt and how it causes summer and winter * * * * * * * *
and have had to imagine just what is going on. Now the "tilt" * * * * * * *
is visible. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

With this 24-hour observation of aircraft travel on * * * * * * * * * * * *
the earth's surface, we get to see the daylight * * * * * * * * * * * * * *
pattern move as well across the face of the planet. * * * * * * * * * * * *
Enjoy! * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
]
*http://www.youtube.com/watch?v=ICjI2u8mFlA

"(recorded by the airplane flight transponders via Geo-stationary
orbital satellites)"

Mmmmm, not quite.

Positions come from what the plane reports to the ATC system
(transponders with GPS) or what the ATC system figures out from dumb
transponder replies to ground station interrogations.

That is, ADS-B squits or Mode-S/ATCRBS replies to interrogations from
en-route and terminal rotating secondary radars (which has radar, but
radar has nothing to do with transponders...).

Not much radar over the oceans or other places.

Then they composited that over a video of the globe.


Dave
--
Cliff