The nuclear forces vs. gravity

I'm wondering, what maintains the stability within an atom? IE: the
interaction between the nucleus and the electrons.
...In our scale of reality, we say the planets etc. are where they are,
because the object they revolve around has bent the space. Does this
same theory apply within the subatomic world. ...And, conversely.. If
you were to look on the grand scale of things, is it possible that there
could be other forces at work, but because we're too small, our
equipment would be incapable of detecting it. ...IE: gravity is very
noticeable to us, but to bacteria, its effect is almost negligible.
Thanks for any response. ...Jon