Why aren't any of the planets in our solar system, Square?

Question

By Square i mean like a Cube.

Answer 1

Actually....... Several of them were when they first formed. But they've 'weathered down' over many millions of years. (Damn!! I think I can feel my nose growing already ☺)

Doug

Answer 2

Actually, it has nothing to do with rotation at all, but something called "self-gravity". As a planet gets bigger and bigger, the gravitational attraction of different parts of the planet gets stronger and stronger. Eventually, the strength of the material can't hold up against this gravitational force and the object collapses down. A sphere is the most natural shape so that the gravity is the same everywhere on the surface.

On Earth (which already has a whole lot of gravity), it's equivalent to trying to build as big a mountain as possible. Over heights of about six miles, the rock can no longer support the weight. No surprise, then, that the tallest mountains on Earth are six miles tall. On Mars the gravity is less, so you can build mountains up to 18 miles high before the rock gives out.

So, even if planets didn't rotate at all, they wouldn't be square. If we look at a whole bunch of moons and asteroids in our own solar system, there seems to be a cutoff around 200 kilometers...any larger than that, and they have to be round due to the strength of their own self-gravity.

Answer 3

The force that holds atoms and molecules together are very strong (nuclear and chemical).

The forces that hold "stuff" together is much weaker. You can take a clump of dirt and crumble it with your fingers. You can even take a rock and smash it to dust with a hammer.

It is very difficult (not impossible) to separate a molecule using only mechanical means. It is impossible to split an atom with a hammer and screwdriver.

On the large scales, planetary surfaces are made of "stuff" that is loosely held together. To make a shape other than spherical requires a lot of energy to hold the "stuff" into a shape.

Gravity increases with the mass of the planet. When the planet gets big enough, the force of gravity is sufficient to break down the weak force holding the "stuff" against gravity (e.g., square corners that rise further away from the centre of the planet) and the "stuff" flows until it takes the shape of a sphere (that is the general shape; local "minor" asperities -- like Mount Everest -- can still exist).

In fact, the IAU's definition of a planet requires that its shape be made spherical by its own gravity. If the object were cubic, it could not be a "real" planet by definition.

Answer 4

No matter what the original configuration, there will always be only one center of gravity. As distinct objects are drawn to the center of gravity (fall) they give up their 'potential energy' which is converted to heat. Decay of radioactive elements adds more heat that can not easily escape and the mass becomes molten. All particles on the planet will try to fall to the least elevation from the center of gravity which describes a sphere (like the surface of earth's oceans). Of course gaseous planets don't need to melt to form a sphere.

Answer 5

Why, are the planets in other solar systems square? I mean cube shaped?

Answer 6

Planets Cannot be square due to relative mass and gravity proportions, and also due to creation of a planet

Planets are created by the formation of gravity pulling rocks and dust into a ball like formation

Answer 7

if you take a drop of water in space and watch it float you will find that it will make a perfect sphere. Because gravity, like no gravity takes presence over an object from every conceivable angle and equally on the surface area in no gravity. Thus a cube has sides with different points with different forces forcing it to be just that. A sphere is natural, and equal

Answer 8

The gravity caused by the mass of the planet "pulls" them into the spherical shape.

Answer 9

Because our Solar System is really cool.

Answer 10

When the planet's rotation around the sun come object planet for a long time ago. (Circling)

Answer 11

for the same reason your head is not Square nature does not like a right angle