why are all the plannets in the solar system round in shape??
483817
Because they started as gas/liquid, and round is the lowest energy state for a liquid.\n\nLike a raindrop.
884425
well the path of the planets is different for each due to the size but the are similar to a oval type shape, gravity hold the planets in orbit and as far as the asteroids they are freely moving until caught by a gravitational pull of a larger object
711289
Actually, those circles are NOT perfect.  They're slighly elliptical.  This is called the excentricity of the orbit.  \n\nBut, yeah, they are more or less on circles, and that's because they want to go straight forward (inertia) but the pull of the Sun's gravity stops them from goind away.\n\nIt like tieing a ball on a rope and turning it around.  It makes a circle.  Let go of the rope, and it will go on a straigt line.  The rope is the Sun's gravity.
66192
It is due to the slight orbital eccentricity of Earth rotation around the Sun. Since the orbit is not perfectly circular the distance between the two bodies varies.
12606
Our world, Earth, is a planet, and planets are round because their gravitational field acts as though it originates from the center of the body and pulls everything toward it. With its large body and internal heating from radioactive elements, a planet behaves like a fluid, and over long periods of time succumbs to the gravitational pull from its center of gravity. The only way to get all the mass as close to planet's center of gravity as possible is to form a sphere. The technical name for this process is "isostatic adjustment."\n\nIf the shape of the Earth were due solely to gravity it would be a perfect sphere (round in 3 dimensions) but it's not, the Earth is shaped like what is called an oblate spheroid. As the Earth spins on it's axis, it produces a centrifugal force that pulls away from the Earth (in opposition to gravity)  at 90 degrees from the spin axis, this corresponds to the equatorial regions. So the Earth bulges out a little around it's middle.
457404
All the planets in our solar system rotate in the same direction with the exception of Venus which rotates *very* slowly in the opposite direction.  It was theorised that it once suffered a glancing blow from a very large object that reversed its spin.\n\nHmm - by rotate I mean on their own axis - not around the sun, in which case all planets go the same direction.
69949
The earth is round because matter attracts other matter, and when they get close they compact together to form spherical objects.\n\nPeople created computers because they kept asking why.\n\nEinstein created an atom bomb because he kept asking why.\n\npeople believe in god because they couldn't figure out why any other way.\n\nThere is music becuase people created it.\n\nPeople have brain because our genetic makeup conducts brain building and reconstruction for our entire lives.\n\nHope that answered your questions
1123910
Only "large" celestial objects are round. Small ones, like asteroids, can be any shape.\n\nIt is the high gravity of large objects that makes them round. As they accumulated from smaller pieces, any piece that was out of round was pulled by gravity "downhill" so the overall shape of the body is round.
623455
The most basic stable physical shapes of revolving and rotating masses is spherical-note not a perfect sphere, because the shape tends to be flatted on the ends. Hence even the sun bulges along its equator and is flattened at the poles, as is the earth-this happens because of centrifugal forces caused due to rotation which throw material outwards, while gravity holds it and pulls it inwards.\n   \nThere must also be enough  mass too to generate enough gravitational force so that a spherical shape is formed. Astronomical bodies which are only a few kilometres across are irregularly shaped-eg. Ceres, an asteroid
457528
It is not just round or oval. It is elliptical. One side is close to the sun and one side is closer to the Oort Cloud, or Kuiper Belt, or maybe the heliosphere, the end of the sun's influence to the galaxy.
32921
Um... what are you asking here?  I think an answer would be that the planets revolve around the sun because the sun it so massive that it makes a small 'dent' in space-time, and the planets 'fall' towards the depression.  There are 9 planets in the solar system, and Earth is the third from the sun and the largest of the inner rocky - planets.  Many of the planets have satellites, called moons.  Earth's moon is called Luna which is (relative to the size of its planet) particularly large.  The planets also rotate on their axises (which is why we have, among other things, night and day).  Nearly all planets also have an atmosphere, a layer of gas that exists above the planet's surface, though only Earth has an atmosphere suitable for breathing.   Beyond Pluto, the last official planet, is a very large void followed by a large collection of planetary fragements (meteors), then another large void.  The solar system ends at a boundry called the heliopause, the outtermost reaches of the sun's solar winds (think of it as a wind made of radiation).  If you travel through the heliopause, you would experience an arguably extreme 'termination shock' as you enter an even larger void into intersteller space.  Okay, that's all I got.
1102975
Because gravity pulls equally in all directions.\nAs soon as the materials that the earth is made of began to gather together under self-gravity, the center pulled equally in all directions.  As heat from friction and radioactivity made much of the early earth molten, gravity pulled it into the most efficient shape -- a sphere.  Because of the earth's rotation and centrifugal force, it's not quite a perfect sphere -- it bulges a bit at the equator and is slightly flattened at the poles -- but it's simply gravity doing what it does naturally.  It's why all large bodies are in the shape of a sphere.
605515
It is not exactly round, just looks that way.\n\nSee webpage below for the correct shape.
266634
yeap, the gravity force and centrifugal force on liquid or molten object (early planets) and gasous objects.\n\nNotice many asteroids are not spherical. They were chunks formed from a solid state already\n\nP.S. I'm afraid I gave a wrong account why many asteriods are oddly shaped. Sorry! Here's the explanation:\n\n"Derek Sears, professor of cosmochemistry at the University of Arkansas and editor of the journal Meteoritics and Planetary Science, provides the following explanation: \n\nPlanets are round because their gravitational field acts as though it originates from the center of the body and pulls everything toward it. With its large body and internal heating from radioactive elements, a planet behaves like a fluid, and over long periods of time succumbs to the gravitational pull from its center of gravity. The only way to get all the mass as close to planet's center of gravity as possible is to form a sphere. The technical name for this process is "isostatic adjustment." \n\nWith much smaller bodies, such as the 20-kilometer asteroids we have seen in recent spacecraft images, the gravitational pull is too weak to overcome the asteroid's mechanical strength. As a result, these bodies do not form spheres. Rather they maintain irregular, fragmentary shapes."
285187
The are round, in short, because it takes the least enegry to do it.\n\nGravity pulls the matter that will make up the planets/sun/... together.  All the forces are pointed towards to the objects center of mass, everything is being pulled inward toward the center.  With everything trying to get as close as possible to the same center of mass, the object develops a round/sphereical shape.  This shape minimizes the amount of potential energy the matter has above the center of mass.\n\nThe reason why some objects (like the Earth for example) as not totally sphereical is because they are roating around an axis.  Since the Earth is rotating on its axis (causing our days and nights), there is a bulge around the equator as the matter located there is rotating faster [tangential speed] than the matter located at the poles.  This faster tangential speed requires more centripetal force [not to be confused with the fictional "centrifugal" force] or order to keep it rotating.  In order to lessen the required force, the matter bulges out a little bid, increasing its radius away from the axis.\nCentripetal force = m(v^2/r),\nyou can see that a larger radius (r) away from the center means a smaller centripetal force is needed.
455949
everything in this universe moves. stars are parts of galaxies. for example our sun is a part of the milky way galaxy. we are in the sagittarius arm of our galaxy which rotates about its centre and as we are in one of the outer arms as the galaxy seems to rotate the sun along with its nine planets revolves around the centre of the galaxy. this is exactly what happens in other stars and star systems. secondly  all stars are round not to mention, every heavenly body is round because gravity makes them round. and the shape we concieve is just because of the phenomenon of scattering of light as the light from the stars passes through various layers of the atmospheres of different densities
993320
Planets are not "round" but in fact "spherical".  Planets are spherical because gravity acts upon each part of the planet, pulling it closer to the center.  A sphere is the most efficient shape to contain the greatest volume with the smallest dimensions.  In the case of a sphere, the radius is a smaller distance from the center of the planet than any other shape could manage, thus, matter naturally forms this shape in the absence of other factors.\n\nIt is important to note that the planets were not always as cool and ridged as they are now.  When the planets were born, they were made of molten elements, and did not solidify until their shape had already taken.  In some other cases, where planets were formed through the collision of multiple bodies, the heat generated by the impact liquified sufficient amounts of the bodies for a spherical shape to form.