Why areall the planets, moons , stars ect round?

Answer 1

Simple answer is because they are so very large.
Planets and stars are made of a massive amount of material. When you get to this level of material the gravity the mass has actually over comes the internal forces of the material and cause it to seek a round shape.

There is a threshold of mass that a planet, asteriod, planetiod has to meat to get this round shape. Once met then it begins to round out and as more mass is added this further helps the becoming round thing.

Hope that helps

Answer 2

First of all none of the objects you ask about are perfectly round. Even Jupiter bulges at it's radius in relation to it's rotation due to centripetal force. Earth as well has a bulge at the equator, also mountains, hills and the like. Also, Mars's moon Phobos is hardly anything but round. http://en.wikipedia.org/wiki/Phobos_%28moon%29

However, I get the meaning of your question.

First is gravity. Over time when a clump of space rock collects other smaller pieces of space debris due to it's small gravity the once odd-shaped piece of rock will begin to create a central point of gravity. Or in the case of a star, the surrounding gases will also generate around a central gravity point. Both are relational to the total mass of the object.

This central point will pull the entire mass to this central point. Over time erosion (not necessarily water erosion) will form the small Planet into a sphere-shape. Tidal forces of nearby objects can shift the shape of objects, so that when they move the small planet will shift closer to a "round" shape as well.

That was a fun question, BTW!

~n

Answer 3

Out of all multi-dimensional geometric figures,sphere has the least surface area.Thus all particles try their best to attain a sherical shape in order to reduce their surface area(place a drop of mercury on a smooth surface;it attains a spherical shape).It is for the same reason that when you pour any liquid in space they attain a spherical shape.
When a new star is born, the gas clouds around it condenses to form planets.The dense gas passes through three states-the gaseous state,the molten liquid state and finally the solid state.When a planet is in the first two states,it attains a spherical structure due to cohesive force(force of attraction between the molecules of same element).Later the molten planet solidifies into a rigid planet like the earth.

Answer 4

It's most likely based on what the shape of the core of the planets and moons are. A pyramidal shaped core could probably produce a pyramidal world, as thats the most stable shape the world's gravity would probably maintain.

Though I'm probably just mistaken.

Keep in mind that none of them are truly round.

Answer 5

erosion. a spheroid shape has the least amount of surface area for any particular volume. it is also even all over. imagine an irregularly shaped rock flying through space really fast. collisions with other smaller rocks, dust, gases will eventually wear it down evenly (over lots of time) on all sides. it's own mass (which imparts its own gravity) depending on how massive the body is, will also keep its mass together.

Answer 6

since planets are composed of smaller clumps of matter the distribution of these materials are affected by gravity. wind, weather which tends to distribute them evenly over a large area.
gravity is why planets are round.

Answer 7

they aren't all round

there are craters and all stars are not round, they just appear that way on earth.