Question about the universe ...........?

Question

The smallest particle including quarks and the largest stars are all spherical in shape. Why can't planets be in the shape of a rectangle, triangle or trapezium?

Answer 1

Gravity, and other attractor forces, pulls all material closely together, and the shape with the most efficient volume is found in a sphere.    

Answer 2

i want to know too. o_o.

Answer 3

The shape of small objects (like people and houses and mountains and small asteroids) are determined by their mechanical properties. You can take a rock and cut it into a particular shape and it will pretty much stay that way.

The larger the object, though, the stronger its gravitational field. Imagine that you want to build a really tall building. You have to make sure it has a really strong foundation, or the foundation will be crushed by the weight of the building and the building will fall. If there was anything really big sticking up on a planet or a star, gravity would pull it down.

If a planet was like a cube, the corners of the cube would be higher than the rest of the planet. Since planets and stars are so big, you cannot build a "foundation" strong enough to hold up those corners! Anything you built it out of would be too weak to hold them up. Gravity would eventually pull them down.

Even solid rock will flow like a liquid, although very slowly, if it is pulled by a very strong gravitational force for a very long time. Corners on a cubical planet or star would eventually just squish down.

Since gravity pulls toward the center of the planet or star, everything gets pulled down into a sphere. However, planets and stars are not really perfect spheres. They spin, so they bulge out a little around the equator.

Answer 4

Gravity pulls towards a center. This naturally forms a sphere or spheroid shape. If your orb was a rectangle, then gravity would not be pulling all points towards the center with the same degree of force. This would defy the laws of nature.