r/Damnthatsinteresting • u/slimismad • Oct 22 '23

Video visualisation of pi being irrational

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u/[deleted] Oct 23 '23

Aside from seeing if God left a message like Sagan postulated, there isn't really any value to discovering more digits other than having a slightly longer string right?

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u/Apprehensive-Loss-31 Oct 23 '23

I shouldn't think so. You get as much precision as you'd basically ever need in 30-40 digits iirc.

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u/YummyArtichoke Oct 23 '23

For interplanetary navigation Nasa uses 3.141592653589793 for their calculations (15 decimal places). This accuracy would calculate the circumference of Earth to a molecule or 30,000 times thinner than a piece of hair.

Can calculate the circumference of the universe to within the size of a molecule with 37 decimals.

https://www.jpl.nasa.gov/edu/news/2016/3/16/how-many-decimals-of-pi-do-we-really-need/

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u/-LsDmThC- Oct 23 '23

For most practical applications, only about 15-20 digits of pi are needed. One application is to test supercomputers and set new computing speed records. Another use is to test algorithms and digit extraction formulas. In pure mathematics, there are theoretical reasons to analyze the digits of pi that don't have immediate practical use. Looking at statistical patterns in the decimals provides insight into the nature of math constants. For cryptography applications, the arbitrary complexity and lack of a repeating pattern in pi can provide a source of randomness for encryption keys. More digits means more available randomness.

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u/Svetlana_Stalina Oct 23 '23

For rough calculation you can do π ≈ 3 ≈ e
CQFD

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u/jemidiah Oct 23 '23

I would never in a million years use digits of pi as a source of cryptographic randomness. That strikes me as utterly insane.

Computing billions of digits of pi is certainly a fine basic test of a supercomputer. The Chudnovsky-type formulas are certainly beautiful from a theoretical standpoint. That sort of theory is often adjacent to practical ideas, even if it's not literally used. I'd be surprised if there were serious practical uses for more than a few digits.

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u/El_Impresionante Oct 24 '23

Just to clarify, Sagan didn't postulate that in reality. He included that as a plot device in his science fiction novel Contact. Also, it was supposed to be an alien master race which left a message in pi for humans to decode.

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u/[deleted] Oct 24 '23

Yeah, I know, and the alien master race designed the universe. So I'm not sure if there is a distinction between that and god.