Or it proves that the aircraft was coming from the southwest on a northeasterly heading while the sun was setting due west. So the sun would hit the north (right)side of the contrail, leaving the southern (left)side in the dark.
Which is exactly how the aircraft was supposedly heading! Surprise,surprise, surprise!
A setting sun would light the underside of the contrail, the part facing the ground (the underside of horizontal contrail NECESSARILY is facing the GROUND) ...
... leaving the TOP of the contrail -- the part facing the sky -- in shade. The only way we could see it would be if our POV was above the contrail, and the contrai was between us and the setting sun.
In the Leyvas video, about 1/3 or less of the right side of the plume is bright, and it is bright becaust it is facing the sun; the remainder of the plume facing the sun is out of our POV. In the Leyvas video, about 2/3 of the plume from our POV is dark; it is facing away from the sun. The plume is between us and the sun, and we are seeing a backlit vertical plume. The sun is lighting it up for the VERTICAL plume that it is.
Plain as the nose on your face. It isn't theory, it isn't speculation, it isn't opinion, it isn't guesswork. IT IS PHYSICAL REALITY.
Again: Yow. THE SUN WOULD HIT THE UNDERSIDE OF THE CONTRAIL, FRIEND!
The majority of what we can ever see, any time, if we are on the ground or even a few thousand feet in the air, from our POV of an overhead horizontal contrail roughtly five miles high, is its underside. HELLO? Knock knock knock???
With a horizontal contrail five miles over our heads, we can only see a small part of what is facing east, north, south, or west, and the part of that rim facing the opposite direction of the sun will be in shade, hence one edge of an overhead, underlit contrail is in shade -- it is the side of the contrail facing away from the sun; MOST of the overhead contrail, at sunset, is being underlit, and therefore the pics you see again and again and again here of contrails shot at sunset, illustrate this -- most of the width of the contrail is brightly lit. This is because our POV is not to the side of the contrail, but BELOW it.
Does not work that way. Sun is below horizon. Contrail is at about 35,000 feet. From an observation point close to sea level, you can only see the bottom of the contrail. You cannot see the right side or the top of the contrail. Physically impossible. The sun is actually lower then you with respect to the contrail and the sun is below the horizon. So from your vantage point the sun is down below the horizon and the contrail should be far above the horizon. Try to picture that in your head. It helps. The contrail should be uniformly lighted from the sun far below. Simple lighting problem for computer graphics people. And they are a whole lot of them around now.
Like I stated before the only chance you have at seeing a contrail at 35,000 feet lighted just like that would be if you mounted a camera on top of Mt. Everest. Obviously you could shoot one like that from another nearby plane at 35,000 feet.
So it is not possible for it to be a plane, unless you think the laws of physics failed at that instant. Later.