Why are all Planets and Moons.........

Spheres? Why don't any planets and/or moons take on any other geometrical shape? Maybe the answer is obvious and I'm just retarded but the thought popped into my head just now. It's so natural to me to see planets and moons as sphere's that it never occurred to me to ask, why? Is there any scientific answeres to this question. Is it because of gravitational pull or some other reason? Why can't there be squarish or rectangular planets or triangular shaped planets. I'm not talking planets with sharp corners or anything but just take on the shape to an extent. Planets and moons and suns( I suppose ) take on a near perfect looking sphere.

The reason why most things are spheres are because of the gravity involved. When masses join together, gravity and compression crush the material into a sphere, because it is the most economic and energy efficient form something could take in space.

~Keeper

Because gravity acts on every single atom with the same strength. If you think about it only a sphere can form because all points on the surface of the sphere have the exact same distance to the center because all points of the surface are being compressed into the earth with equal strenght

[edit on 5-4-2009 by stevedel0]

Well, imagine a raindrop, as it falls, it doesn't miraculously form a square, that would go against a lot of laws. it become round at the bottom.

It more or less has to do with the spin, these are giants objects spinning, and frictions cuts it down to find the best way possible to spin more effeciently. Comprende?

www.pa.msu.edu...

curious.astro.cornell.edu...

Here are some good sites, to better explain.

Enjoy

Hydrostatic equilibrium

The IAU's definition mandates that planets be large enough for their own gravity to form them into a state of hydrostatic equilibrium; this means that they will reach a shape that is, if not spherical, then spheroidal. Up to a certain mass, an object can be irregular in shape, but beyond that point gravity begins to pull an object towards its own centre of mass until the object collapses into a sphere.

from - en.wikipedia.org...


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The reason planets and moons are infact round is the same mathmatical caluculation fro pi.

Logical

they are round because so is the universe.. its the outcome of the equation that made the universe..

im sure in some other universe they are square and other odd symmectric shapes..

basicly its the most simple shape one can get other than a tryangle..

the universe is based on simplicity.. so the simplest object shape to keep things iin order would be a sphear..

there is no other simple shape we can get as its 1 line..

understand? same principle gave you 2 eyes 2 legs and makes everything symmeticral

Thanks to all for the info and yes I do understand. Just wanted the scientifical answer put into lamens terms. Makes sense but I was just wandering that with all the mysterious and strange happenings with our known universe, why there wasn't just one planet, moon, sun that didn't have a shape of a sphere. Just curious.