I've been reading about the work of Marie Curie recently after a friend filled me in on what she did (never having had much of an idea previously) and it's all very interesting.
What I can't understand however is what real impact her discovery of radium had for the development of physics in general? I mean in the textbooks and websites I've been browsing, Curie is made out to be some sort of physics pioneer - but I can't see where her discoveries specifically moved the study of physics forward (don't get me wrong, I'm sure she was extremely influential, I'm just trying to understand why).
How did the discovery of radium/radioactivity impact the study of physics? What impact did Marie Curie have in actually moving towards modern physics? I can only seem to find a variety of claims that she did impact physics, rather than how specifically - it all seems a bit odd.