Try bringing two of your fingers closer in the back drop of a light source and you would observe this:
Long before your fingers actually touch, the edges magically seem to touch each other. How is this even possible?
Transit of Venus
When scientists were observing the transit of Venus from Earth i.e when the planet Venus passes directly between the Sun and Earth,they faced a similar problem.
At the moment when Venus should
nearly touch the edge of the sun, the circular planet began to elongate.
And they noticed the same phenomenon for Mercury as well (which has no atmosphere).
What is causing this optical phenomenon?
The physics behind this beautifully bizarre optical phenomenon will be revealed tomorrow on FYP!.
But since this is something that you can all try at home, we strongly encourage you to play around with this and get a feel for it. It requires only your hands and a source of light.
Once you do, try to hypothesize a solution for this behavior.