# The edge of the universe

When you dig into the history of cosmology, some things catch your eye. Things like the “boundary conditions” in Einstein’s 1917 cosmological considerations in the general theory of relativity. Or something Willem de Sitter said in his 1917 paper On the relativity of inertia. Remarks concerning Einstein's latest hypothesis. He said this: “if the gμν at infinity are zero of a sufficiently high order, then the universe is finite in natural measure”. There’s also something Paul Steinhardt said in his 1982 Natural Inflation paper. He said this:…