If a bipolar planetary nebula is viewed exactly pole-on, what shape might its visibility suggest?
Answer
A simple sphere
When a structure that is intrinsically bipolar (like opposing cones) is viewed directly down its axis of rotation (pole-on), the resulting apparent shape observed is that of a simple sphere.

Related Questions
What mass range defines the stars that evolve into planetary nebulae?What object remains at the center of a planetary nebula providing the energy for its glow?What primary physical process is responsible for making the ejected shell visible as a nebula?How long does the visible phase of a planetary nebula typically last on astronomical timescales?What atomic process generates the observable light emitted by the energized gas cloud?What factor in the progenitor star's environment often leads to complex, non-spherical planetary nebula shapes?Why were these objects historically given the misleading name 'planetary nebula'?How does the illumination mechanism of a planetary nebula differ fundamentally from a reflection nebula?What specific chemical element's strong emission is often responsible for younger, highly ionized nebulae appearing blue-green?If a bipolar planetary nebula is viewed exactly pole-on, what shape might its visibility suggest?