Planets Shape?

Question

Why is every known planet a sphere?

Answer 1

Because even if the planet is made out of solid rock, the gravity exerted by this billions of tons of material deforms it into the most stable state, which is a sphere. If you had an irregular shape the size of a planet, it would simply collapse into a sphere under its own weight.

Answer 2

A solid body needs to be a certain size before it's gravity pulls it into a spherical shape.

The body does not have to be fluid or gaseous to be spherical. Gravity can shape solid bodies. For instance, even though we usually associate the moon's effect on us as ocean tides, it actually pulsates the solid crust of the Earth in a tidal motion, though small compared with ocean tides.

Asteroids are generally mishapen. I don;t think anybody knows the exact cutover, but a solid body will probably assume a spherical shape above say 1000 miles wide.

Mars moons are tiny and mishapen, whereas Jupiter has large moon's, like ours, that are spherical, as well as tiny ones that are not.

Perhaps we should define a planet as a body big enough to be spherical, but not big enough such that it's gravity squeezes its interior enough to start nuclear processes - that is when the body becomes a star. It is reckoned that a planet 60 times more massive than Jupiter would become a star.

Answer 3

Probably the most efficient use of the energy put into making the planet. Seems like spinning would be involved and spinning anything in a circle makes a sphere or near-spherical object. Like Earth there are probably many oblate spheroid bodies out there.

Answer 4

The large rocks in space are not spherical. when u have a many pieces they all have gravity for each other which pulls all together and the continual squeezing together is what shapes it all into a sphere that is what the earth is trying with the tectonic plates continually shifting to balance the spin of the earth Study hard u may need it

Answer 5

that's a stability between gravity and inter-particle stress. Gravity will attempt to pull each and all of the debris in direction of the centre of mass, whilst the forces between debris will attempt to maintain them aside. If the debris are very fluid, then they fill out a gravitational 'equipotential' which may well be a sphere. the better the gravitational stress, the lots greater in all probability the particle are to 'circulate' to a solid state. In different words, debris can tend to circulate downhill. on the floor of a sphere there is not greater 'downhill' to holiday. think of what occurs on the earth - plate tectonics pushes up mountains, yet gravity motives landslides and such so as that the debris tend to holiday downhill. If gravity is low sufficient, i.e. the planet very small, it won't unavoidably be a sphere. subsequently many minor planets (aka asteroids) have atypical non-around shapes.

Answer 6

It makes more sense. What would you think if you saw a planet in the shape of a triangle rotating around the sun?

Answer 7

planets are not at all a sphere they are all cuboids it just looks this way on tv. stupid

Answer 8

Because they start of as gas or hot liquid rock. Gravity is symmetric in 3D.

Answer 9

because the gravity of the large mass pulling in on itself while spinning

Answer 10

Spinning and gravity