Close one of your two eyes. Move your head close to the monitor and watch concentratedly to the left circle if you closed your left eye.
You should look to the right circle if you closed your right eye. Keep watching and move your head slowly backwards while checking the other circle. What happens? And how is that possible?
Why has the sky most often a blue color? And for what reason becomes the sky becomes suddenly reddish when the sun sets? Why does this red color only appear during a sunset or sunrise and not when it is noon?
Why are the European Ariane rockets launched from the
Korou site in French-Guyana, South-America, and not simply from
some place in Europe where the rockets are partly built?
