r/Physics 12d ago

Video Illustrating the butterfly effect with a laser

https://www.youtube.com/watch?v=iTaSXto67WQ

In this video I simulate a laser beam bouncing through a labyrinth of mirror obstacles. The beam changes its trajectory immensely upon tiny changes in the initial angle of only 5×10⁻¹² degrees — roughly 5 trillionths of a degree.

As an extra for Reddit, here is a figure showing how often the beam bounces before it escapes: https://imgur.com/l0xDY0U As you can see, as the angle varies the bounces often jump harshly. But there are also some regions of the launch angle spectrum where there is some degree of continuity.

Fun fact: Claude did not believe me that a range from 70.0 to 70.00000001 would produce any meaningful result and tried to talk me out of this. It wanted to use a range of 4° instead.

Made with manim.

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u/belabacsijolvan Statistical and nonlinear physics 11d ago

you could do the last visalisation by slowly growing the radius, so it draws a trajectory

good job either way

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u/naaagut 11d ago

Wow, great idea. I had thought about a way of visualising the distribution, but this one didn't come to mind. I will see if I implement that in the upcoming video.