Why are all celestial bodies oval or round?
550230
spinning of a steller body creates gravity in equal directions. however not all steller bodies are round or oval. The moons of Mars are not. They are irregularly shaped because their gravity is far less than that of our moon.
425798
Our planet earth and for that matter all planets, moons and stars are generally spheres, not cubes or cylinders or odd shapes. Some small galactic bodies such as asteroids comets do have odd shapes, but planets, suns and stars and even moons look like spheres. That's because, when they were formed millions of years ago, they were essentially molten liquid. Gravity and meniscus forces (surface tension) cause the object to take on a rounded shape--and it cools in that position. Do you remember seeing astronauts squeezing out juice or other liquids, they immediately become round in space.  It is the nature of gravity too pull uniformily toward the center--as the distance from the center increases, so does the gravitational force. You can think of gravity as a force that points inward toward the center of all things that have mass-- so that every part of the surface (especially liquids)is pulled evenly toward the center, resulting in a spherical shape.\n\nPlanets are not perfect spheres because there are other forces acting on the planets too which are trying to stretch them--rotational forces, etc. Because they were once hot moltent liquid, they buldge in the middle for these secondary centrifigal forces. Earth and the moon reflect this phenomina. Although gravity keeps planets close to spherical, there are other forces that cause deviations from the basic spherical shape. For example, the rotation of the earth once every 24 hours, causes an apparent centrifugal force which creates a bulge at the equator. In fact the earth's diameter at the equator is 7,926 miles while the diameter between the poles is only 7,900. \n\nNote that planets and moons had to be a liquid or they would not have been able to escape the gravitational force of the nearest larger body. Remember that liquid will seek the path of least resistance as it moves. In otherwords, an impact on the earth would cause a splash of moltent material that could escape the earth's atmosphere at the exact angle (path of least resistance) to be able to exit the planet's atmosphere without burning up. Once it exits into space, the gravitational pull of the larger body will pull it into orbit. It will stay in orbit until it is acted upon by a larger force. Fortunately, we haven't seen any larger forces since the earth was created and therefore, the conditions will remain for millions of years into the future.
422854
The moon although is a sphere, but it is so far away that it appear a flat round disk. there is nothing strange about this and if people are not educated that moon is a spherical rock, they'd probably think it's a round flat disk.\n\nBut for me, I see it as a hole in the ceiling.
805592
first: by world, do you mean earth? \nIf so, think about all things spinning, are they not always more or less round or oval shaped? Actually so is the earth. \nOn the other way,I think that by spinning, a lot of things get that shape. Especially as like the stars and planets, they tend not to be in a fully finish state. Ok, that is my answer but I am no astronom only a nurse... MC
811234
Because the Earth is round, the widest point could be from top to bottom.... it all depends on which way you are looking at it.
80
Largely because of the massive amounts of gravitational force involved.  A sphere is the only sustainable shape when talking about forces of that magnitude.  Stars are incredibly dense towards their core, and over billions of years the matter will coalesce in a sphere like shape.
370
The Earth is round because it is a large body, and gravity tends to make large bodies round because that is the gravitational efficient configuration for the matter to be in.\n\nThere are a few reasons you can encounter non-round bodies in space:\n\n1) the object is small (for example asteroids), so it's gravity has less say proportionally on the shape\n\n2) It has experienced a catastrophic collision with a large body\n\n3) It is under very strong rotational or tidal forces\n\n4) It is expelling matter/energy in the form of cosmic jets, nova ejecta, etc.
157120
This goes along with the question of why don't we fall off the earth if it is round. The answer is because gravity is holding us (and the water) down.
943945
Round seems to be our perception of the future, and of higher technology.  Look ar all our movies, the cars are always rounder than those of today.  WE think aliens are futuristic, so I guess that means they should be round.
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.
1069514
By Newton's law of graitation any mass is attracted by another mass. Since the planets are matter like our Earth, the pull of gravity in all directrion make the planet spherical.\n\nThe spin of the planets about their axes actually make them close to  ellipsoid of revolution and not spherical. Our earth is also  close to ellipsoid of revolution.
288737
The ellipse is a result of the mutual gravitation of two massive bodies. The center of mass of each sun-planet system is somewhere between the center of mass of the two bodies (it's still inside the sun, though), and each body revolves around the center of mass. Since both masses are moving, they orbit around each other, resulting in elliptical orbits for both (however, since the sun is always orbiting a point within the sun, it's not as noticeable. Unless you're an astronomer.
530735
two reasons, gravity and angular momentum.  Gravity tends to pull matter into one centralized spot, but angular momentum must be conserved.  That mass that escaped being part of the sun attracted mass to centralized locations, what became the planets, flattening things out to a disk shape
868944
Bodies beyond a certain mass are spherical due to the nature of gravity which pulls them together. But there are many asteroids and comets that are small and irregularly shaped because gravity can not overcom the strength of the material.
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
605515
It is not exactly round, just looks that way.\n\nSee webpage below for the correct shape.
483817
Because they started as gas/liquid, and round is the lowest energy state for a liquid.\n\nLike a raindrop.