why are planets spherical?

Question

is there a reason?

Answer 1

Planets are shaped like a sphere because gravity forces them to. Also, planets are not perfectly spherical but are a little bulging on the sides and long on the top and bottom.

Answer 2

Premi Shantini has it right, at least as far as earth is concerned.
centrifugal force (from the earths rotation_ makes it bulge slightly at the equator. this is about 43km greater at the equator than around the poles! Not very much at all. Because of the effects of gravity from the sun (and other nearby stars and large planetary bodies) the planets orbit is an elipse and this is part of the reason that earth is more or less spherical. A planet grows from a rather small accretion of matter in the beginning so I guess you could picture it like a pearl becoming beautiful and round over time though it starts with a rough piece of sand as its core!

Answer 3

Planets tend to be spherical (more or less) because the gravity pulling on its mass tends to pull everything into the least volume possible (a sphere). Although there are numerous theories on planetary formation, the bottom line is that if the gravity of the body in question is stronger than the structural material forming it, it will be spherical shaped. This is why smaller shaped bodies (like the asteroid Vesta or the martian moon Phobos) are shaped more like lumpy potatoes.

Answer 4

It's partly to do with gravity and partly to do with the strong magnetic field at the core, in fact the two may be intertwined. Basically, a planet is suffiently large to be spherical, that was one of the arguements last year when the powers that be decided to downgrade Pluto to a dwarf planet. They got hundreds of thousands of letters from schoolchildren asking why they thought Pluto wasn't a planet when it was round. Bit slimplistic, sorry.

Answer 5

All the planets of our solar system first began to form in an immense cloud of drifting gas and dust in space. Within this cloud (..called a 'nebula'..) there were regions more dense than others. These dense regions had more gravity and thus pulled in more material from all directions towards the center. The resultant shape was spherical.

Answer 6

Everything in this Universe of ours tries to get to the state of least energy.

The planets also follow the same rule ; When they are spherical they can expect to have a very small momentum about their axis and hence a small energy.

But the continous rotation of the planets also flattens them at the poles and hence they become elliptic in shape

Answer 7

Planets are not spherical. They all spin. The earth, for instance turns once in what we call 24 hours.All the others spin at different speeds. This makes them spead a bit around the equator. So they are slightly oval shaped, Further round the equator than round the poles. Trust me!

Answer 8

because the center of gravity of the mass that is the planet is in the center so it pulls almost the same from all sides forcing it is the a spherical shape. so basicly gravity makes planets the shape they are.

Answer 9

The force of gravity pulls them into that shape.
Some moons do not have enough gravity or mass to pull themselves into a spherical shape.

Answer 10

because they tried it with a square or a triangle, the other side NEVER gets any sunlight......so they started a petition but was ignore by the gods, the darker side of those square planets decided to run amok and blew themselves up thinking they're can get this msg to the god...it did....so the next couple of galaxy, god made it round....