2007-02-05 05:51:03 · 17 answers · asked by Torontonian 2 in Science & Mathematics ➔ Astronomy & Space
saves turning a corner
2007-02-05 05:59:11 · answer #1 · answered by traveller 7 · 3⤊ 1⤋
A sphere is the smallest 3 dimensional shape possible. If matter is attracted to other matter, it will unavoidably form the smallest shape possible. Now this is only true for planets that have had a long time to form. There are plenty of celestial bodies out there that are not round, but their creation were abrupt.
Its kind of the same reason that bubbles are round. The outer pressure pushing into the air wants to even out all the "bumps" on the outside.
2007-02-05 14:11:05 · answer #2 · answered by Anonymous · 0⤊ 0⤋
It is an example of "hydrostatic equilibrium", which is why rain drops are round. Basically, for very large objects the strength of rock is less than the force of gravity trying to smash it all into the center. There are some bumps, or mountains, but on a planet with high enough gravity, like Earth, a really tall mountain cannot support itself against its own weight.
2007-02-05 14:03:36 · answer #3 · answered by campbelp2002 7 · 3⤊ 0⤋
If you think about it, as the planets form from a dust cloud, gravity and erosion will force them to be round. Every particle is pulled toward the center of the planet.
2007-02-05 14:07:18 · answer #4 · answered by Gene 7 · 0⤊ 0⤋
Only when it's asked on here about 3 times a day....
It's because any other shape requires energy to counteract gravity. Gravity pulls towards the center of mass, that's why there are limits on how big a mountain can get on each planet (if it's rocky), it can't be square unless it is much smaller like an asteroid.
2007-02-05 14:04:30 · answer #5 · answered by Anonymous · 1⤊ 0⤋
I have wondered about this, and I decided it was round because it orbits and spins on it's axis.
Maybe all planets form a sphere as a result of all the spinning and orbiting.
2007-02-05 13:58:51 · answer #6 · answered by fizzents 4 · 0⤊ 0⤋
All planets have a rotation motion,and in time,became round.
2007-02-05 13:57:40 · answer #7 · answered by Leonard B 2 · 1⤊ 0⤋
Earth for example is round because of gravitation. Since everything attracts everything else, Earth had attracted itself together before it became solid. Any "corners" of Earth have been pulled in so that Earth is a giant sphere.
2007-02-05 14:04:58 · answer #8 · answered by hintzruby 1 · 0⤊ 0⤋
AJ's answer is correct.
In addition, surface tension and gravity made them round shape, when they were still in dusty stage.
Just like a bubble, surface force 'tension', smooths out all other shapes.
2007-02-08 14:08:24 · answer #9 · answered by chanljkk 7 · 0⤊ 0⤋
my theory, is because gravity is the same throughout every area of the planet, hence the ground settles at a similar "gravity rate", making it round.
Hope this helps, Peace.
2007-02-05 13:56:50 · answer #10 · answered by urbanvigilante 3 · 1⤊ 0⤋
Randomness. Make a rubberband ball. At first it won't look like a sphere, but if you keep adding the bands, eventually it will be a sphere.
2007-02-05 14:01:49 · answer #11 · answered by jjayferg 5 · 0⤊ 0⤋