For those who use the American mm/dd/yyyy, it suggests 3.14 With an error of about 0.05%, it’s a good enough approximation for many uses. And those who use the more common dd/mm/yyyy notion can wait for the 22nd of July for 22/7. At 0.04% from the mark, this one's a slightly better approximation.
But just how much Pi do you really need? Eight digits is overkill for most engineering tasks. NASA uses 16 digits .. 15 to the right of the decimal .. to navigate around the solar system going beyond Pluto. The most I can imagine would be to construct a high quality circle the radius of the known universe, about 46 billion light years, to the diameter of a hydrogen atom,. You’d need 38 significant digits for the task.
xkcd has a piece on approximations that’s painfully true. For some back of the envelope calculations in astrophysics and cosmology you can get by with crude approximations.
It’s also Einstein’s birthday. Pie, being a homophone of Pi, seems to the a good bet for the day. I have it on good authority he loved cherry pie and ice cream, so there you go.
He’s one of a dozen or so people who have quotes improperly ascribed to them. He was a joker and much of what he did say is often taken out of context. But here's a real one I love. Shortly before his death he was asked to offer advice to young people. His reply was published in Life Magazine.
"The important thing is not to stop questioning. Curiosity has its own reason for existence. One cannot help but be in awe when he contemplates the mysteries of eternity, of life, of the marvelous structure of reality. It is enough if one tries merely to comprehend a little of this mystery each day." A. Einstein 1955
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