why are all the planets and the moon and sun neally all round?
409220
big bang didnt produced planets. it produced gases and small particles. when the gases started concentrating at a point in space, they experienced huge forces of gravity. and thus got molded in a shape which offers minimum volume(SPHERE).
1027284
because the sun's gravitational pull is much greater than the earth's...same reason the moon goes around the earth and not the other way around
562236
Its earth and venus...the reason behind it is due to their some what similar size, mass of planet, rotation and revolution time and gases in some cases. hope so u satisfied with my answer.
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
48080
coz it is move together with other planets in constant maner around the sun
1058600
both are always in the sky. sun goes round the earth and the earth goes round the moon. depends on the time of year moon cycles etc etc
582912
The sun, moon, planets, I guess this is about all I can think of!
59556
It's due to the formation of the planets themselves.  the gases and the dust spun around the sun as the star formed itself, and congealed into the planets we know.  And since they spun as they formed, they started the spinning on their axis as well.  \n\nBesides, we'd be either cooked or frozen if the Earth didn't revolve!\n\nHarley's wrong.  The moon DOES spin on an axis.  However, its spinning is on par with the Earth's spinning, thus you only see the one side of the moon.
534368
the satelites of the sun are planets \nthe satelites of the earth are moons\nthe satelites of the moon are asteroids
1116527
The Moon rotates at just the right speed so that it always keeps one face pointed toward the Earth. Almost all moons in the Solar System keep one face pointed toward their planet. \n\nThe moon rises in the east, and sets in the west. It moves from east to west, right? If you think about it, you should realize that much of the moon's apparent motion is due to the spin of the earth. The moon appears to go around the earth about once a day. And, you probably know that the moon actually takes about a month to go around the earth. That's where we get the word "month."\n\nWhy don't you perform a simple observation. Look at the moon, some night, and see where it is with respect to the stars (or with respect to the sun). You don't need to know the stars very well, but you probably want to ignore the planets (Venus, Jupiter, and Mars, mainly, as their motion complicates this observation). Night after night, the moon moves against the background of stars. See if you can tell which way the moon is moving, against the background of stars.\n\nAnother simple observation would be to keep track of when the moon rises (roughly) or sets from night to night. Does it rise later each night, or earlier, or what?\n\nYou will see that the moon moves west to east, fairly rapidly. \nWhich way does the earth spin? Well, the stars, sun, moon, and planets all seem to be moving east to west. So the earth is spinning in the opposite direction, west to east. Hey, the moon is also moving west to east, coincidence? Well, the earth is moving around the sun from west to east. In fact all nine of the planets are moving around the sun from west to east. And, all of the planets, except Uranus (which is lying on its side) and Venus (which is spinning slowly backward), are rotating from west to east. And most of the moons, of the various planets, are orbiting their planets from west to east. And most of the asteroids are orbiting the sun from west to east.\n\nIt's not a coincidence. The Solar System started out as a cloud of dust and gas, and it was rotating from west to east. That's why most of its parts are still rotating and orbiting from west to east.
20941
Consider that the Earth moves around the Sun because of gravity, like a ball on a rope moves around your hand when you swing it.\n\nNow, consider some of the laws of gravity (in english):\nCloser objects = more gravity to eachother\nBIGGER objects = more gravity to them\n\nThe Earth is 1/100000(lots of 0's, maybe more) the size of the Sun, so we really don't affect it much, but it keeps us going around it like nuts! (once a year, right?)\n\nThe Moon, however, is not sooooo different from the size of the Earth (yes it's smaller, but not 1/10000etc(like the Earth vs. Sun thing), AND it's CLOSER to the Earth than the Sun is (WAY CLOSER)!\n\nSo because it's kindda nearer to our size, and it's kindda close, it's got 2 big check-marks for LOTS-O-Gravity!
9937
It's because the world in question is ruled by unicorns and merry elves. In "that" world it's only natural that everything is either square or circle. Here of course we have irregular shapes and other geometrical figures like triangles, trapezoids and such. Must sound very strange to you I believe.\n\nUs earthlings, we have strange ways.
368925
Other planets since all nine planets revolve around the sun so when you're on one side of the sun,other planets are probably on the other side!
464601
Earth revolves around the sun because the giant nebula out of which the solar system formed was spinning and the angular momentum is conserved, and earth spins because of the initial config. Why it revolves in an ellipse, see this\nexplanation at http://www.mathsnet.net/cabri/feynman.html
712687
If you imagine a solar system that includes the sun and the Earth,and no other bodies, the Earth would travel about the sun in an ellipse (strictly speaking, the Earth and the sun would travel around their common center of gravity in ellipses).  An ellipse has two foci, which are points that define the ellipse in the same way that a point defines the center location of a circle.  Because the sun is so large and the orbit is so nearly circular, both of the foci lie near the center of the sun  So it is not correct to say that one of the foci is the sun -- both foci are in the sun, but they're really just mathematical points that define the shape of the orbit.\n\nWhen you add more planets to the mix, things get much more complicated, but one can think of each approximately elliptical orbit separately, and then there is a different set of foci for each pair of bodies if one neglects the influence of the other bodies.
833064
All the planetary objects in the solar system revolves round the Sun. Then how can the earth be the centre. The center of the Solar system must be at the Sun. The Sun is relatively stationary in the solar system.
543004
Technically, the general rotation direction of the Sun and most planets is a leftover from the original solar nebula from which the Solar System formed.  As the planets and Sun coalesced, they retained the rotation direction of the original nebula.\n\nDuring the coalescence phase, asteroid-size chunks collided and stuck together.  As more and more of these chunks collected, the planets grew in size.  However, these chunks not only brought mass to the mix, they also brought momentum.  Since most of the materials were probably all travelling in more or less the same direction, the general rotation direction of the growing planets remained the same.\n\nIn the case of Venus and Uranus, it is suspected that a major collision between the planet and another body literally tipped the planets over due to an off-center orientation of the collision.  Uranus tipped over on its side, probably due to its size relative to the other body.  Venus, being smaller, tipped so far over that its rotation was reversed.