aeroplane puzzle.?

Question

two aeroplanes crossed each others path in the sky, their jet streams made an X in the sky. i was lying on the ground looking at this. I looked back about two minutes later and the X had moved a few degrees in the sky (south i think). So how did this happen?

I dont believe it was airflow or wind, the x was still perfectly intact. the lines were still straight.

I thought it might be the earth rotating, but does that mean that the atmosphere doesnt rotate with it and does it rotate that fast?

Answer 1

The answer is that the condensation trails are composed of water vapour suspended in the atmosphere. They're basically really long thin clouds.
To be in an atmospheric environment conducive to the formation of vapour trails, the aicraft would probably be at an altitude of about 30,000 feet. At this altitude, the air is relatively stable; there is little turbulence and the airflow is smooth and flows in one general direction depending on conditions; not like the air at ground level which is typically quite variable and unstable.

The X-shape you saw in the sky didn't break up because the air at that altitude was obviously very stable. It moved across the sky because the air at that altitude was all moving in the same direction at the same speed. Consequently, the vapour trails moved with it, and stayed in relatively perfect form, unbroken due to the lack of any turbulence.

Answer 2

The wind blew the streams to a different place in the sky.

Answer 3

The earth rotates??

Answer 4

Because there is wind.

You have to also think that the X probably dispersed a little or grew.

Answer 5

Did the earth move for you?

Answer 6

Air flow would move them

Answer 7

the wind