2006-11-07 01:20:33 · 8 answers · asked by Syed 1 in Science & Mathematics ➔ Astronomy & Space
Most are actually more ellipsoid in shape (i.e. not perfect spheres).
I'm no astronomy/physics expeert, but I think it has something to do with gravity and rotational forces.
2006-11-07 01:22:53 · answer #1 · answered by Anonymous · 1⤊ 0⤋
Everything in the Universe with mass attracts every other thing in the universe with mass, and in time they accumulate into larger bodies. At first, the gravitational force that binds them to one another may not be the strongest force that binds them together, and they can grow into almost any shape.
After a certain point, however, the effect of gravity will attract particles closer to the centre of mass, and the sheer weight of the material will cause it to flow to reach that lower energy level. Objects will literally fall downhill until there is no downhill...
Unlike what we've seen in the movies, most asteroids may not be single ominous lumps of rock or metal, but collected aggregates of dust and boulders and fragments of other cosmic debris. Mining asteroids may be more a matter of sifting dust than drilling holes.
Somewhere around 100 kilometres in diameter, the gravitational force in a body is stronger than even the structural strength of the matter supporting it, so the object flows into a spherical shape. This shape might be affected by tides or rotation or density of local areas, but beyond a certain size, almost all the serious concentrations of matter you find will be an ellipsoid of some sort.
So, for once and for all, it's official - The World Is Not Flat. ( the big ones, at least. )
2006-11-07 02:37:47 · answer #2 · answered by quasar_1998A 2 · 1⤊ 0⤋
Once planets were formed, they were in hot molten form and with the affect of gravity it tried to take a shape with smallest surface area. A sphere is known to have the smallest surface area compared to other shapes for the same volume. hence the shape.
2006-11-07 01:28:56 · answer #3 · answered by 6 · 0⤊ 0⤋
The sphere is the object with the smallest surface area for the volume.
That is not to say there are not any disc shaped planets, or toriodal worlds, or any other shape; we haven't seem them all.
2006-11-07 01:24:00 · answer #4 · answered by credo quia est absurdum 7 · 0⤊ 0⤋
Gravity.
2006-11-07 01:21:48 · answer #5 · answered by The Nutmeg Master 1 · 0⤊ 0⤋
Check "Best of Answers". Someone already answered this question with a very good answer.
2006-11-07 02:23:39 · answer #6 · answered by Randy G 7 · 0⤊ 0⤋
because of the gravity and pressure exerted on it
2006-11-07 01:24:53 · answer #7 · answered by genius sonia 3 · 0⤊ 0⤋
because of gravity
2006-11-07 02:44:16 · answer #8 · answered by bprice215 5 · 0⤊ 0⤋