2007-02-02 19:23:51 · 11 answers · asked by saravanan 1 in Science & Mathematics ➔ Astronomy & Space
because that is the shape of the least resistance. the pull of gravity pulls all parts of the planet equally so it pulls it together as a sphere. it's the same reason when you blow bubbles they start out stretching from the wand then when they break free they turn into a sphere.
2007-02-02 19:28:53 · answer #1 · answered by smokesha 3 · 5⤊ 1⤋
It's a balance between gravity and inter-particle force. Gravity will try to pull all the particles towards the centre of mass, while the forces between particles will try to keep them apart. If the particles are very fluid, then they fill out a gravitational 'equipotential' which would be a sphere. The higher the gravitational force, the more likely the particle are to 'flow' to a stable state. In other words, particles will tend to move downhill. On the surface of a sphere there is no more 'downhill' to travel. Think what happens on earth - plate tectonics pushes up mountains, but gravity causes landslides and such so that the particles tend to travel downhill. If gravity is low enough, i.e. the planet very small, it won't necessarily be a sphere. Hence many minor planets (aka asteroids) have irregular non-spherical shapes.
2016-05-23 22:35:06 · answer #2 · answered by Anonymous · 0⤊ 0⤋
All the matter in the universe is composed of matter which are compounds of molecules of elements . the moleules are composed of atoms which are the smalles unit of any element.All masses hae a natural force of attraction. the strenght of this force dependson the size of the mass and the force exerted by that mass weakens over disances in proportion to the square of the distance .
now the atom being a smallest component of the massof any matter , has a tendency to attract mater in proportioin to its size . the proton of the atom is known to attract and pull the electrio to wards the center of the atom wher it is located .thios dot of he proton haveing adorce should exert it in all directions around it uniermly .so all the matter that is pulled towards the center of the protoon should get smeared around the proton evenly around . so the mass aound the proton gets built up around the cehter point uniformly.The same way the big masses having a force of atraction pulling all things around it to twards the center , should be exerting a force of attraction uniformly around it ain all direction. So the matter around the mass should experienxce an equal amount of force in all directions around the center .This should cause the matter around the center of the mass being spread unformly to a specific depth or height around h center .it is only in the case of a sphere all the points in the surface on all the sides are at equal distnces and is connected to the center in a straight line . The forceof attraction around the center acts around the center with equal force on all direction around the center .natully this shouyld result in the ,mass assuming a sherical shape only .; because in no other shape all th epoints on the surface will be located at equal distance from the center .of the body.
2007-02-05 05:26:11 · answer #3 · answered by Infinity 7 · 0⤊ 0⤋
Gravity pulls eveything together.
Each and every particle, rock, drop of water, and yes, you, pull towards each other.
It has been calculated that mountains on Earth can not be higher that 20km (Everest is 8km). If it is higher than that, it will collapse under its own weight.
The earth's crust underneath would give way and the whole mountain would sink a little.
So, any other shape than a sphere is not possible, because you would have bits sticking out that would cave in.
That goes for any shape - cube, triangle, cylinder - only a sphere does not have bits sticking out of it.
2007-02-02 19:48:14 · answer #4 · answered by mgerben 5 · 0⤊ 1⤋
They are spheres as long as they are big enough for gravity to pull then in that shape
Some asteroids as you may have noticed are potato shaped etc because they don't have enough gravity to overcome the strength of their rocky make up.
2007-02-03 03:08:25 · answer #5 · answered by Billy Butthead 7 · 0⤊ 0⤋
In this universe every particle tries to attain more stabilised position. When the matter from Sun was seperated, it packed up and became cool and spherical.
2007-02-03 16:19:10 · answer #6 · answered by ♥ ΛDIƬΥΛ ♥ ııllllııllıı 6 · 0⤊ 0⤋
stars are formed by the explosion of supernova and when they explode there is a spiral formation of dust and other gases are there. when the central mass is fullfilled then when other solid particles colide they form masses they turn out to be planet. due to presence of the stars gravity they get round further they get it from the rotation and revolution. but they are not perfect round but oblate spheroid.
2007-02-03 03:47:31 · answer #7 · answered by JAKE 3 · 0⤊ 1⤋
they are spherical in shape because they rotate on their axis at a very quick speed.therefore,a layer of the mass is formed around the axis.thus,they are spherical in shape.
2007-02-04 21:33:25 · answer #8 · answered by Heady 3 · 0⤊ 0⤋
gravitation, rotation and so on create the basic sphere. some of the smaller stuff isnt that round though
2007-02-02 19:27:01 · answer #9 · answered by Anonymous · 1⤊ 1⤋
It's God's favorite shape.
2007-02-03 14:48:41 · answer #10 · answered by seflack5 1 · 0⤊ 1⤋