Why does gravity always create a sphere?

Some say the moon was rocky debris that gravity made into a sphere which now orbits our planet. Indeed, all the planets and suns [that we are aware of] appear to be spherical; as is our planet.

So why does gravity create spheres? What is it about gravity that makes a sphere the easiest or best prospect?
Could this be key in understanding and then manipulating gravity?

Originally posted by mandroids
Some say the moon was rocky debris that gravity made into a sphere which now orbits our planet. Indeed, all the planets and suns [that we are aware of] appear to be spherical; as is our planet.

So why does gravity create spheres? What is it about gravity that makes a sphere the easiest or best prospect?
Could this be key in understanding and then manipulating gravity?

Because gravity is equal in all 3 dimensional directions.

and why would that make a sphere?

reply to post by mandroids


A sphere is the smallest shape you can make.
With the material you have...

The reason planets appear spherical is because gravity compresses the planet into a shape that most evenly distributes the gravitational force among the planet’s mass.

I see. even a perfect sphere? gravity would smooth it that way?

Originally posted by mandroids
and why would that make a sphere?

Because its attracting matter to collect in one spot from all directions.

Imagine if it tried to create a cube. Mass creates gravity. If it were a cube, then the gravity would be unevenly distributed and the cube would just collapse on itself and create a sphere anyway.

well, thats my point..why not a cube?

As much as it could yes, obviously depending on size etc there is bound to be some undulation on the planet depending on what it is made of..

further..

Whether it is shaping water droplets, stars, soap bubbles or planets, nature seeks to minimize the surface area needed to contain a given volume, and the shape that keeps volume at the absolute minimum a sphere.

Any object in weightless space larger than a couple of hundred miles in diameter has enough mass for its gravity to overcome large-scale irregularities and force it into a spherical shape. This gravitational compression also generates significant amounts of heat at the center of the planet. This heat melts, or at least softens, any solid materials within the planet, facilitating the planet’s collapse into a spherical shape.

Objects in space smaller than about 100 miles in diameter, such as most asteroids, comet nuclei and small moons, lack the mass to create a gravitational field strong enough to compress themselves into spheres. so they have odd looking shapes instead.

reply to post by mandroids


That's been answered like 4 times already.

basically gravity pulls things to a central point and its also not a perfect sphere

Originally posted by mandroids
well, thats my point..why not a cube?

Because matter, where two edges meet, will have less of a gravitational force than in the center of the sides and will be pulled to the center where the gravity is greater until the pull from one side is equal to the pull on another. THEN, you have stability which comes in the shape of a sphere.

Originally posted by mandroids


So why does gravity create spheres? What is it about gravity that makes a sphere the easiest or best prospect?
Could this be key in understanding and then manipulating gravity?

When things are being recollected into a combined or compound form they tend to turn to spheres when being spun, so maybe the Universe is spinning* like the lab devices that spin material of bio to study and the gravity is just the holding mechanisim..

It don't, the earth is not round or even pear shaped as some people think. The earth is an oblate spheroid which is bulging at the equator due to density-variations, gravity, and centrifugal-force.

And here is a map of earth gravity field, it is far from spherical.

Originally posted by mandroids
well, thats my point..why not a cube?

Are you reading the replies?

Originally posted by mandroids
well, thats my point..why not a cube?

Maybe if the Universe was stationary in movements and only moved up and down left and rignt?!

Originally posted by definity
it don't, the earth is not round or even pear shaped as some people think, The earth isn't really pear-shaped and it isn't a sphere either. The earth is an oblate spheroid which is bulging at the equator due to density-variations, gravity, and centrifugal-force.

And here is a map of earth gravity field, it is far from spherical.

edit on 26-1-2012 by definity because: (no reason given)

Its getting there.

Originally posted by Chamberf=6

Originally posted by mandroids
well, thats my point..why not a cube?

Are you reading the replies?

I am, mr friendly,but i wanted to learn a bit more.

Originally posted by r3axion
reply to post by mandroids

 

That's been answered like 4 times already.

like 4? is that quantum physics?

OK, thank you for answering that question for me.