# When, and by whom, was the Schwarzschild metric first taken to be valid for all radii greater than zero?

The metric was originally defined to be valid only from the surface of a black hole outward but somewhere along the line it was extended inward to include the region under the event horizon.

This extension of the metric was, of course, what gave us the definition of Schwarzschild black hole and I've been curious for some time about how the extension first came about and who did it.

• Yes, its one of the lesser known quirks of GR that the Schwarzschild coordinates aren't the ones Schwarzschild used :-) However this seems more like a history of science question than a physics question. Maybe it would be better suited to the History of Science SE. – John Rennie Aug 1 '18 at 16:32
• @JohnRennie … Thanks John. I posted it there. Should I delete it from here and, if so, how do I do that? – dcgeorge Aug 1 '18 at 17:19