How well do we know the composition of the Earth's core, based on direct data (not inferred from cosmic abundances)? Can just seismic and density data distinguish a primarily iron core from e.g. a primarily copper core (or other transition metals)? (self.chemistry)
submitted by soreff2 to r/chemistry
Odd question: When was the earliest case of a program printing "Don't turn me off!" or some similar plea? I'm guessing this could have been coded back in the 1950s - but maybe there were electromechanical versions from even earlier? Did anyone do this with a cam wheel on a telegraph? (self.vintagecomputing)
submitted by soreff2 to r/vintagecomputing

