Share the knowledge!
Light in the Shadows: the Poisson Spot
Key Facts In This Video
If you shine a light on a perfectly spherical object, you will see a bright dot in the middle of its shadow. 00:33
See an example of a Poisson spot: 05:24
To see a Poisson spot, you need a coherent light source, which is why the spots don't commonly appear in everyday life. 07:04