Well, here’s another thing I didn’t know until I was informed by Twitter.

Way back in 1876 – forty years before Einstein presented his Theory of General Relativity – the mathematician W.K. Clifford (who is most famous nowadays for the Clifford Algebra) presented a short paper in the Proceedings of the Cambridge Philosophical Society in which he speculated that space might be described by Riemannian rather than Euclidean Geometry.

Here are a couple of excerpts:

and

The paper does not contain any actual equations, and his concentration on small scales rather than large was misguided, but it is quite remarkable that he was thinking about such matters such a long time ago!

Unfortunately Clifford died very young, in 1879, at the age of 33, tuberculosis. Had he lived longer he might have been able to develop these ideas a bit further.

As a postscript I should mention that Clifford had an impressive beard.