Planets are uniform bodies that moves around the stars in orbits.By moving in orbits,they conform to a regular,repeating path or pattern in space.They do not release visible lights,as is found in Moon or the Sun.Hence,they occur as dark spacial bodies,depending on other stars for illumination.Mercury,Venus,Earth,Mars,Jupiter,Saturn,Uranus,Neptune,and Pluto are all members of the solar system of planets.The universe is even a bigger chunk ,containing many
more stars,both known and the yet-to-be discovered.
In order to discuss this topic effectively,it would be decent if one could create a new conception in space,as is being perceived by Japan’s Maruyama Shigenori,a leader in world’s geophysics.Accepting that the planets are living super-human will help,as one can devise a taxonomy(or method of classification) suitable for the solar system.All the planets are of the species called planetea,because they have several common features,and each will have a genus equivalent to its common name.For example,Mercury is Mercuria planetea,Venus is Venusia planetea,Earth is Earthie planetea,Mars is Maris planetea,Jupiter is Jupiteria planetea,
Saturn is Saturnia planetea,Uranus is Uranusia planetea,Neptune is Neptunea planetea,and Pluto is Plutoea planetea.Therefore,the following are the reason,both major and minor,why the planets are round :
1.GRAVITY PULL
What is gravity?Gravity is a force which attract a static or moving body to a common center.The configuration you achieve when you pull a moving mass,such as the planets to a common center, is a round.One can demonstrate this process on Earth with a football tied to a long rope,and swung round and round ,the observer holding it standing at a point or center.This is also another variation of what children do call merry-go-round.Whenever everything gets pulled down to a particular center,as this demonstration shows,you generate a round or sphere.Again,large objects such as planets are known to have stronger gravitational fields.Hence,isostatic adjustment requires that the only way to get all of the mass as close as possible to a planet’s center of gravity,as much as possible,is to form a sphere.Strictly speaking,a cube,pyramid,cone,tetrahedron or frustum will not work.In a cube,for example,one reason is that the edges are on higher levels far more than other points on its body from its center.
2.HEREDITARY COSMIC DUST FEATURE
According to the concept of solar nebular,the planets are known to be produced from particles and dusts.Space dusts or particle dusts consist of dust grains and aggregates of dust dust grains.Whether cometary dust,asteroidal dust or interstellar grains,they all have the spherical round shape.If the Earth,representative of the planets has been produced from a combination of particles and dusts,which have round micro shapes,then it justified to say ,by invoking heredity into the game,that the product resulting from this amalgamation would also be a round macro object.This situation may be compared to the children emerging from a parent,with a lot of hereditary traits and similar physical features.
3.THE ORBITING PROFILE
The regular,repeating path which an object in space take around another one is described as an orbit.Orbit may also be perceived to be the result of a perfect balance between the forward motion of a body in space,such as moon,and the pull of gravity on it from another body in space,such as a star.In an orbit,there is a steady tug-of-war between an object trying to go forward and away and another trying to pull it in.The Earth orbits the Sun,as do the other eight planets,traversing the imaginary,circular,disk-shaped,or elliptical loop called orbit.If the planets were not round,then,maintaining the orbiting profile would create so much problem in the solar system.
4.THE LAW OF SIMILARITY
According to the law of similarity,two bodies are considered similar if they have one or more look-alike features between them.Dusts and particles are now known to be the molding blocks of all the planets in the solar system.Both dusts and particles are round in shape.If the Earth or another planet is just another particle in space,then,according to the law of similarity,it is only justified that the Earth or the other planet should be round too.
Extending the law of similarity to all the planets is only right justified.Again,the Sun
presents a round profile to all the bodies around it,which are expected to orbit it.Once again,the law of similarity suggests each of those bodies should have a round shape like the Sun.
5.PERFECT AS A SHOCK ABSORBER
The planets are not the only body orbiting the Sun.Asteroids,meteorites,comet,and other stars also have their own orbits too.And their orbit,pathway,or trajectory could intersect with that of the planets in the solar system,once in a while.Recent comets that passes over the Earth’s atmosphere are good examples.While the Earth completes its own orbit in about 365 days,most other bodies are not that lucky.Their orbiting process may take hundred to
thousands to even millions of years.One of the last comet observed by scientists on Earth was reputed to traverse our planet once every hundred years.If an orbiting asteroid should in error collide with a planet,for example,the Earth, the round shape will offer some protection from falling out of its own orbit.However,in such situations,the accident may leave holes and craters on the surface of the planet or Earth.Guess what would happen if the shape had been a cube,with straight sides and pointed edges.Your guess is as good as mine.Crumbles that would
capsize the process may be the lot in such a situation.
Moreover,while the roundness of the planets is adorable,one should also not forget that none of them approximates a perfect sphere.One is reminded of the shape of the Earth,an oblate
spheroid,also called geoid,because it bulges out at the center or equator.Again,Newton’s first
law of motion,also called the law of inertia,says that a stationary body continues to be at rest or if under uniform motion,continues to move unless compelled by some external
forces to do otherwise.This law serves to justify the bulge at the center of the Earth,caused
by the speed of the planets mass at the equator.
Our solar system has come along way.Emerging from the postulated solar nebular,over time,a collection of nine planets result.A close look at these planets,including Mercury,Venus,Earth,
Mars,Jupiter,Saturn,Uranus,Neptune,and Pluto shows they all have round shapes,though not a
perfect sphere.And these roundness could be traced to the effect of gravity pull,hereditary cosmic dust features,the orbiting profile,the law of similarity,and the shock-absorbing feature of the spherical masses.
Sources
http://en.wikipedia.org/wiki/Planets
http://www.pa.msu.edu/sciencet/ask_st/031198.html
http://www.sciam.com/article.cfm?id=why-are-planets-round&topicID=2
http://wiki.answers.com/Q/Why_are_planets_round
http://en.wikipedia.org/wiki/Newton’s_laws_of_motion
