how is it possible *planets shapes question*

how is it possible that every planet is a circle/sphere, but theres no weird shaped planets like a box or just a weird shape. this has always bothered me lol.

I'm no planetary scientist, but I do know this much...Nature LOVES a sphere.

A sphere is the shape in nature for which a given volume of matter will have the smallest surface area; and conversely, it allows the smallest given surface area to surround the greatest volume (this is two sides of the same coin, but slightly different concepts.)

The forces of gravity will create a sphere because when gravity pulls together a volume of matter, the most efficient shape is a sphere since a sphere can have the most volume with the least surface area.

Sphere = Least surface area = Efficiency -- and nature loves to be efficient.

It's something (but not exactly) like a soap bubble...the skin of a bubble will surround the largest volume of air with a given amount of soap provided. However, the force at work in forming a bubble is suface tension, not gravity. A bubble is the "other side of that coin" I was talking about, and probably has little (or nothing) to do with planetary formation.

The fact that most large celestial bodies a spheres probably also has something to do with the fact that in a sphere, every point on the surface is equidistant to the center of gravity, which is the center of the sphere.


[edit on 12/31/2007 by Soylent Green Is People]

In a word: Gravity.

Once a body reaches sufficient mass its own gravity, acting equally around the center of mass, will form the body into a spherical shape.

Of course, smaller bodies, like asteroids and comets, are all sorts of odd shapes.

[edit on 31-12-2007 by IAttackPeople]

reply to post by IAttackPeople


That explains why the older I get, the fatter I get.

They may have to bury me in a sphere.

There are some "lumpy objects", but they are of a smaller size. Basically, just large rocks with anywhere near planetary mass.

reply to post by IAttackPeople


True...I bet if an irregularly-shaped rocky asteroid suddenly turned fluid or even just a little more plastic, its gravity would eventually form it into a sphere (as long as no other forces were acting on it.)

[edit on 12/31/2007 by Soylent Green Is People]

guess:
I think spin plays an im[ortant role in shaping the planets. If its a cube (dunno how that will even exit initially) if you spin it long enough it eventually becomes round kinda like pottery and anything flying off would probably be attracted to the center of the planet again by gravity. Also when you make a snow ball you don't make it cube do you?

Originally posted by Soylent Green Is People
I bet if an irregularly-shaped rocky asteroid suddenly turned fluid or even just a little more plastic, its gravity would eventually form it into a sphere (as long as no other forces were acting on it.)

Sure thing. We've all seen liquid being played with in a zero-G environment taking-on a spherical shape before being gobbled by a thirsty astronaut.

reply to post by DarkSonic


I don't know about spin being a major factor in shaping a planetary body but spin DOES make a planet slightly "squashed" as the centrifugal force makes the equatorial region bulge.

For example, the Earth's equatorial diameter is 7937 miles while the polar diameter is 7900 miles.

Originally posted by IAttackPeople
In a word: Gravity.

Once a body reaches sufficient mass its own gravity, acting equally around the center of mass, will form the body into a spherical shape.

Of course, smaller bodies, like asteroids and comets, are all sorts of odd shapes.

[edit on 31-12-2007 by IAttackPeople]

Exactly what I was thinking. Couldn't of said better myself

if you have a lawn, the next time you water it, just step back and
view the drops......it's naturally occuring in our reality.

Yes
The energy eminates from the dead center and flows outward
in a spiral design..this is known as the pthygoran musical spiral.
(All is sound/vibration) and spinning.it follows the ancient mathimatical formulas like "the golden Mean"' "Phi" ' "the Fibonacci sequence"
and other ancient sciences.

it follows a specific path and growth rate that is dictated by
the laws of natual science.

Let us not forget Iapetus, Saturn's moon that somewhat resembles a Walnut. Of course we could always throw Mimas into the mix as well. But I guess they are both spherical still.