posted on Jun, 5 2009 @ 01:11 PM
reply to post by wonderworld
Ah, but why cant it be that two passenger jets are crossing over at the same time?
See cause I've been on flights before where I can see another
jet passing just behind us a few thousand feet below our plane and roughly the same time. Not uncommon either.
As for the grids, well thats another explanation. When you have a busy air corridor, with numerous aircraft traveling in all four directions (north
west south east) of course you will have more contrails. Now \, lets throw in some upper air dynamics. Say there is a jet stream right over one
such area, which is blowing from west to east. Now, lets have about 5-10 passenger jets that are flying north to south routes. There is a 10-15
minute delay between each aircraft. Now, they are at altitude where persistent contrails are able to form and last. Now what we have here is
something akin to a "conveyor belt" in the sky. The west to east winds are blowing the contrails from west to east. From the ground you will see a
whole series of line forming in almost parallel form. Now, its obvious that the contrails are moving over and another is being laid down in the same
place. Its just that winds have carried the contrail a certain distance. Now, lets throw in some cross-traffic going east to west, and they are a few
thousand feet lower, below the north south route. Now at this level the winds are blowing from roughly south to north. What will happen is pretty
much the same thing. What happens then? A grid pattern. And yes, winds can and do change directions with height. You will have lines crossing lines
perpendicularly which creates a whole "grid".
[edit on 6/5/2009 by GenRadek]