What I suppose I mean is: is there any use for pi calculated to this level of accuracy? It's done using formulae. Surely we couldn't actually measure a circle's diameter and circumference this accurately, or anywhere close to it?

If the only purpose is to prove that computers have advanced, is there a more useful proof?

If all the water in the atmosphere were to condense at the same time, how high would

the sea levels rise?

I have been reading a Sci-Fi story in which a physicist uses a 'Pi- meter' to investigate local disturbances in space-time.

This set me thinking. It is easy to see that circles of differing radii drawn on a curved surface (for example the surface of a sphere)would have different values for circumference/diameter when both distances are measured on the surface, and that for such figures pi would differ from the usual value corresponding to plane geometry.

Given then that gravity arises from a curvature of space, and that we live in a gravitational environment, the question arises - 'how does the local practical value of pi differ from that calculated by the usual analytical processes ? - After how many decimal places does the practical value of pi differ from the theoretical Euclidean one ?'.

As a supplementary question, - could an ordinary spring balance serve as a 'pi-meter', and if so what is the relationship between the weight of a 100g mass and the local practical value of pi ?