This is the electron probability density distribution for an atom in its lowest, or ground, state: n=1, l=0, m=0. It has a simple spherical shape.

     The above planetary nebula is called Abell-39, and it has a remarkably symmetric spherical shape.
Source: H.E. White, Physical Review, vol. 37, pg. 1423, 1931. Source: http://gemini.tuc.noao.edu/jacoby/pn_gallery.html.


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