Sky Has No Limits...! So Do I....!

Important Property of Sphere:
Of all the solids of given volume, sphere has the smallest surface area. Also, conversely Of all the solids of given surface area, sphere has the greatest volume.
Keeping this property in mind, lets analyze why the planets are spherical....

Lets dip our finger in a glass of water, and allow it to drip naturally. When we analyze the shape of the droplet, it is a "Sphere". Try placing a drop of mercury on a table. The shape of the droplet of mercury is also "Sphere". This phenomena is due to the "cohesive force"...don wonder "what is cohesive force?" Its the force of attraction between the molecules of same element which brings the molecules closer. Lets converge the cohesive force on the water droplet. Since the water droplet contains molecules of same element (water), the force of attraction between the molecules bring them closer so that it becomes "spherical"....
You might wonder why spherical? why not cubic or rhombus ?.....
This is the place to incorporate the important property of Sphere...
Of all solids of given volume, sphere has the smallest surface area. Now lets put both the cohesive force and property of sphere together. The force of attraction between the molecules bring them closer to have a smallest surface area. Thus any particle tries to achieve near perfect sphere, to have a reduced surface area. This is not the case in solids because the molecules are tightly packed and cannot be displaced.
The formation of planets are from a dense cloud of gases around a new born star.
When a star is newly born, the dense cloud of gases surrounding it condenses from vapour to solid. The dense gases passes through 3 stages.
1. gaseous state,
2. molten liquid state,
3. rigid solid state.
When the planet is in first 2 stages, it attains the shape of sphere due to cohesive force between the molecules (same element), the final stage is the solidification of the molten liquid state into rigid solid planet like "Earth"...