Why are solar systems and galaxies flat?
Question:
Answer:
Some galaxies are spherical, but many are flat because they are spinning. Centrifugal force wants to throw everything outward, but gravity wants to keep everything in. Gravity acts kinda like a retaining sphere, whereas the centripetal force has an axis. Imagine taking a metal globe and randomely sticking magnets all over it, now spin the globe on its axis, the magnets will tend to move to the equator.
This is most likely because of the gravitational waves. I would assume they are at a maximum at that point in space and that is why the planets stay in such an arrangement. However not all are in one plane.
It looks like a ball
It has to do with the gravitional pull of whatever the system centers around.
Galaxies do not have to be flat! In fact, elliptical galaxies are, well, elliptical in shape. the ones that you think of as flat are the spiral galaxies, but even those do not have to be flat; our own galaxy is a spiral that is warped by the gravity of nearby galaxies. Also, it is only the main spiral part of spiral galaies that is (relatively) flat. All spiral galaies have large, spherical halos consisting of old stars and globular clusters. Finally, a number of galaxies are 'irregular'; with no easily describable shape at all.
As for the solar system, the main planets are very close to being in the same plane but it is not an exact thing. But the asteroids and comets are fairly evenly distributed around the sun. Also, the Kuiper objects (like Pluto) tend to have orbits that are quite far from the plane of the main planets.
A. as mass is pulled into a gravitational center, it begins to orbit the mass center. As galaxies were forming, they began spinning b/c of this. If you were to send a probe directly at the sun, as it approached, it would begin to move around the sun due to frame-dragging and other gravitational phenomena.
B. The stars have to keep moving or they would be sucked into the center. Now imagine a perfect sphere of stars around a galactic center. How will they spin? One axis will eventually be favored because as any stars try to spin on some other axis, they will eventually collide with other stars.
More Questions & Answers...