What is an oblate sphere?

Answer 1

A spheroid is to an ellipse what a sphere is to a circle. If you rotate an ellipse around either its major or minor axis (the major axis is the one that runs from pointy end to pointy end, the minor axis is perpendicular to this, running from flat end to flat end) the three dimensional projection you produce is a spheroid.

If the spheroid you produce has a shorter polar diameter than equatorial diameter, it is said to be oblate, and looks a bit like a soccer ball would if you squeezed it between your hands. The alternative, with a longer polar diameter than equatorial diameter is a prolate spheroid.

Answer 2

Any of a variety of three-dimensional shapes that have one cross-section which is circular and one which is elliptical. Those shaped like spheres that have been stretched in one dimension are called prolate spheroids, those shaped like spheres that have been squished in one dimension are called oblate spheroids.

Hollow prolate spheroids possess the same internal reflective property as ellipses, but in three dimensions instead of just two. Look up "echo chamber".

Answer 3

It is not a perfect sphere, but has an oblong (oval) shape seen from one angle, although circular when seen from the perpendicular. An example is a spinning planet, pulled down at its poles and bulging slightly at its equator, due to the acceleration of its mass. If the planet were to stop spinning, gravity would pull it back into more-or-less spherical form.