why is the shape of all planets sphrical?

Question

guess

Answer 1

Have you ever seen a triangle spinning? Like everything else in nature, their design goes along with their purpose and how they go about in their existence.

Answer 2

Yes, Planets seem to be spheres, not cubes or cylinders or oddball rocky shapes. Some smaller bodies such as asteroids or Mars moons Phobos and Deimos, do have odd shapes, but larger bodies like the nine planets and most of their moons do look like spheres. That's because of the nature of gravity. You can think of gravity as a force that points inward toward the center of the planet so that every part of the surface is pulled evenly toward the center, resulting in a spherical shape.

Of course, planets are not perfect spheres because mountains and valleys and even skyscrapers are all deviations from the spherical shape. However, as planets get larger, gravity gets stronger, until eventually large objects on the surface are crushed under their own weight. That's why we don't have mountains that are 50 miles high or skyscrapers that are 2,000 stories tall. Planets stay basically spherical because any large deviations get crushed.

Although gravity keeps planets close to spherical, there are other forces that cause deviations from the basic spherical shape. For example, the rotation of the earth once every 24 hours, causes an apparent centrifugal force which creates a bulge at the equator. In fact the earth's diameter at the equator is 7,926 miles while the diameter between the poles is only 7,900.

Answer 3

the surface of planets is more or less spherical ( it's not perfectly spherical). the reason for this is that the force of gravity is equal in all directions on the planet.
if you consider the planet to be made of many number of concentric shells. then the gravity is trying to pull them to their common centre( for the sake of imagination, consider a cricket ball). there would be a compressive force along it's surface whose resultant will balance the force of gravity.( now consider the ball being compressed from all the sides. you won't be able to compress it much, because a force, as mentioned above, will prevent it from getting compressed).
in the existence of spherical symmetry these compressive forces are balanced very easily and effectively. any other distribution will face problem of getting balanced and finally it will some what break. due to self gravity the matter will come close again and form another shape which would be a better shape than previous one but may not be spherical. the process will continue until a more or less spherical shape is formed.

Answer 4

A sphere is the most efficient shape for a solid that is bound by gravity. Every body of any shape has a center gravity. A sphere of uniform material has its center of gravity at the *center* and all the material is distributed around the center in the smallest possible configuration (the lowest potential energy state). To a first approximation, this is why celestial bodies like planets and stars are very close to spherical.

Answer 5

Gravity is the reason, since in space it pulls equally in all directions, this forms a sphere. If the mass is small, like an asteroid, it can have very irregular shapes, but when it gets as big as a planet, gravity tends to 'mush' it into a ball. Before you say, hey what about mountains, mountains are very small compared to the radius of a planet, so they are small imperfections. Any extremely large irregularity would be slowly collapsed by gravity.

Answer 6

Because -

1. Spherical is the most natural shape.
2. Own gravitation pulls its surface towards its centre. And a sphere is the shape where surface area is minimum.
3. Centrifugal force
4. Always rotating

Answer 7

no planet has a definite shape to describe....it is so because most of them have craters created by meteors and other celestial bodies in the universe....
we are differentiating them on an approximate calculation of its sizes only.....the shape of all the SPHERICAL PLANETS WILL BE FLATTER AT THE CENTER AND IT GOES ON DECREASING AT THE EDGES, GIVING CYLINDRICAL SHAPE AT THE SIDES ALONE.....SIMILAR TO OUR EARTH..

Answer 8

They aren't spherical. Most are slightly irregular oblate spheroids. Gravity (inward) and centrpetal acceleration (outward) are the major forces.

Answer 9

Gravity from the sun might have a bit to do with it

Answer 10

i think its because of land you wouldnt see a cube shaoed planet wiuld you?