Q:

earth is spherical , does it mean the ground on earth is like a ball?

I know earth is spherical in shape.
Does this means earths atmosphere is spherical in shape or the ground/(land+water combined) is in spherical shape.
I have some doubts if the second is true.

since the earth is rotating around itself and  revolving around sun in the same time. When we see sun in the afternoon on top of your head. it can be actually you are upside down looking onto sun which is under you.

I'll add my other doubts once some one answers my question.

A:

The form of the Earth is a approximately (to a very good approximation) an oblate spheroid (difference between the polar diameter and equatorial diameter is ~20km which is ~1/300 of the mean diameter). The shape is distorted by tides (both in the solid body as well as the sea) and by topography. Topographical variation is about +10 to -10km (height of Everest to depth of the Challenger Deep).
Up and down are defined by the local gravity vector, which to a good approximation is pointing into the Earth towards its centre. Hence wherever the sun is, down is into the Earth's surface (in the direction colloquially know as down)

