Thread: Why does everything with gravity attract objects to orbit it in a disk shape?

Its kind of hard to work the question. For example though, why are all solar systems "flat" and all the planets rotate on a plane instead of on different planes around the sun. The same is true for galaxies (at least it seems). So what I am saying is, why do all objects that orbit around something orbit on the same "axis".

The reason that everything always becomes flat or "disk-shape" is due to the rotation of said celestial objects. If you have a large floating object and it starts to rotate you can imagine that it will bulge at the middle. This is due to the outward centripetal force (centrifugal force) starting to exceed the gravitational attraction of said celestial object. As it spins faster and faster, pieces can fly off and form other orbiting bodies etc.

When two or more bodies orbit in different planes, gravitational interactions between them will alter those planes over time. This process will continue until the probablity of an orbital plane-altering interaction is minimized -- that is, when all bodies are approximately in the same plane.

It's not true. Artificial satellites we've put around the earth are in all sorts of orbits.

But where it is true, it has to do with the formation of those objects. If they all started from a gas cloud with the same rotation, then they're going to keep that general orbital motion as they condense. So it is implying a common origin.

An act of GOD

Not all solar systems are "flat". There are many planets out there which orbit on different planes around our Sun. Take Mars, for example. Its orbital plane is at a different angle than Earth's. Same for Pluto and other planets beyond the Kuiper belt.

http://www.astro.virginia.edu/class/oconnell/astr121/im/orbital-inclinations-FB.gif
http://infinitewell.files.wordpress.com/2008/09/orbital-plane-1.jpg

The answer is centered on fractals at the surface of the Sun and the resultant curve created in local space around each segment. Moving outward from the Sun places you in regions where the discharge of these fractals moderates and blends.
Believe me, to get from where I talk about these fractals in Chapter Eight to the answer to your question will take quite a bit of your contemplation, but there it is.
Interestingly, my thoughts recently have been working on a "Chicken or Egg" question about where the planets are in the Solar System: does the planet's mass and composition set itself around the Sun or does Sol call the tune? It is a complex question of viewpoint.

Orbits of system in the universe are almost circular and lie within a nearly flat disc called the ecliptic plane. Kepler's laws give a description of the motion, including the orbit of every planet in our solar system.

Refer to the link.

This has to do with what is known as the Conservation of Angular Momentum. What this means is that, once you start spinning something about a central point or axis, it will continue to spin in that same orientation until you do something to change it. This is why gyroscopes keep spinning in one direction, and why bicycle wheels tend to be stable once you start moving.

The planets in the solar system, and the stars in the galaxies (the spiral galaxies anyway) formed or were gathered from an original source that was spinning in one direction. In the case of a solar system, it was a cloud of dust and gas that formed around a spinning star. In the case of galaxies, it was probably a star cluster that formed around a spinning black hole.

In any case, the material gets dragged along by gravity to spin in the same direction as the central object. It will keep spinning that way until something comes along to change it. Since it is all spinning around the same axis, it will form a disk shape oriented perpendicular to that axis. In the case of the solar system, the planets formed as this dust cloud condensed, but it still kept spinning along that same axis. It is - as mentioned by another responder - a clear indication that all of the major planets formed from that same rotating disk cloud.

There are exceptions. Pluto's orbit is quite eccentric to the ecliptic plane, indicating that it was probably an object that was trapped from the Kuiper Belt after the initial formation of the other planets. But in general, the reason is that once things start to spin in one direction, they don't want to change - unless we do something to change them.

As mentioned elsewhere, any slight initial spin increases as the system shrinks, due to conservation of angular momentum. This spin has an axis and a plane. Stuff in the plane has a centrifugal force outward, stuff along the axis can just fall to the centre. The result for most stuff is that it ends up in or near the plane.