Observation of a curious phenomenon on 14 August 2010 at 17h45
Sitting in a train coming from Brussels, Belgium, and travelling in the direction of Liege, I spotted something strange through the window. The train was 6 or 7 km away from Zaventem [Brussels Airport - Editor's note] when I noticed a plane that had taken off from the transverse runway and was moving in a direction quasi perpendicular to the one followed by the train. The plane's angle of climb was approximately 30 degrees.
As it gained altitude, it began to turn slowly in the direction of Louvain. I could see it change course. Then, brutally, something strange happened: the plane seemed to climb vertically, while at the same time carrying out a rotational movement on the spot. I was very surprised by this apparent immobility and continued to watch. After about ten to fifteen seconds, the plane regained its normal trajectory in the direction of the railway and continued to climb.
I knew I was looking at a plane that was turning to the right and gaining altitude while I myself was in a train going in the direction of Louvain.
I was also aware of the fact that similar movements had been reported by witnesses who believed they had seen a UFO and that certain "believers" have used such reports to support the idea that there is no craft on earth capable of performing this type of manoeuvre, thus proving that "UFOs" exist.
I don't agree with that, so I had to find an explanation for the apparent immobility and the apparent vertical movement combined with a rotational movement on the spot.
Obviously, the fact that, during a certain period of time, the plane appeared to stay at the same place, was an optical illusion. This apparent immobility resulted from two simultaneous movements: one from the plane (flying at a speed of about 200 m/sec) and one from the train (travelling at a speed of about 40 m/sec), both heading in the same direction. The apparent vertical movement resulted from the fact that the plane continued to climb during this apparent "immobility". Moreover, when a plane approaches you from a distant point in the sky, it will also appear to move upward in the sky (even if it maintains the same altitude).
The same explanation applies when an ascending plane moves in the direction of a stationary witness and then makes a turn.
Conclusion: the unusual sight of an aircraft that appears to rotate on the spot and at the same time rises vertically, is an optical illusion that can be explained by a confusion between "apparent movement" and "real movement".
[Roger PAQUAY is a Belgian physicist (University of Liège, 1963) and retired honorary director of a technical school.]
Thanks to Mr. PAQUAY for sharing his interesting experience with us.
On page 63 of Allan HENDRY's The UFO Handbook
(Sphere Books Ltd, London, 1979), a similar incident is described. We quote:
"(...) the witnesses in the car watched a plane at sunset near an airport fly horizontally for what they guessed to be five minutes, climb very steeply for five minutes, and then resume its horizontal flight for another five minutes".
Note that, as is the case in many UAP reports, the estimates of duration as given by these American witnesses are probably overestimated.
It is not hard to fathom how strange this illusion may look at night when planes are not always recognized for what they are.