[dynoman]

Here's #6;

The photo which shows the shadow of the contrail in the sky. There's a shadow because the setting sun is in line with a contrail that basically parallel to the earth's surface. If the contrail was vertical there would be no shadow. Here's the photo;

[dynoman]

ping to post 49

[DuncanWaring]

There's a shadow because the setting sun is in line with a contrail that basically parallel to the earth's surface. If the contrail was vertical there would be no shadow.

Let me see if I've got this right - when the sun is setting and the sun's rays are parallel to the earth's surface, an object also parallel to the earth's surface and also to the sun's rays will cast a shadow, but a vertical object, perpendicular to the sun's rays, will not cast a shadow?

Next time you're out at sunrise or sunset on a clear day, take a look at a handy vertical object (tree, telephone pole, etc) and see if it casts a shadow.

In my world, that's pretty-much a universal occurrence.