Why are galaxies often flat shapes such as elipses and spirals?

Question

I understand some galaxies are shaped as clusters but what accounts for flat galaxies when gravity makes grouped matter the size of stars and planets form spheres?

Answer 1

As matter in space begins to collect due to the force of gravity, it begins to form into increasingly larger clusters. This matter naturally spins very slowly, but as the matter draws itself together, then it begins to rotate faster and faster (like an ice skater, who draws their arms inwards to make themself spin faster on the spot. Try it on an office chair: spin round on it with your arms & legs outstretched, then draw them in). This spinning exerts an outward ("centrifugal") force on the matter, which tries to throw all the matter from the axis of spin. This force works against gravity, stopping the matter from shrinking into the centre. The only way peices of matter can now get closer to one another (without moving towars the centre point) is if they all align into a disc shape.

Also, planets are not perfect spheres. Earth is slightly flattened at the North & South poles due to it spinning about it's own axis. Many planets have rings of matter orbiting about them, which do not crash into the planet, but all lie along the same plane (like a disc too)

Answer 2

Here again is where dark matter and the effects of the 'pressure' of its enormous gravity could come into play during the formation of a galaxy, especially spiral galaxies like our Milky Way.
I have a theory that I'm currently working on that dark matter causes normal matter to be 'squeezed' flat in shape do to the tremendous effect of its gravity when the galaxies are forming! We do know that dark matter 'keep' the spiral galaxies from just simply flying apart and 'chunks' of its arms flying off into space! At least we theorize it is dark matter which holds the galaxies together . . .
Now why are stars and planets round and not flat, if that were the case? The answer being, that dark matter, even though it's gravity is extremely strong, can not effect such 'small' matter formations like stars and planets!!! Just galaxies and galaxy clusters!

Answer 3

There's really two answers; the first is because all the stars in a galaxy (or, planets & debris in a solar system) rotate around the center of gravity. Any clumps, or slightly more massive groups of stars/dust/ice tend to pull other clumps of stuff down to it's orbital plane. So, if you have a LOT of stuff in a big spherical glob, moving around a common center of gravity - eventually, it'll flatten out, and start to form a spiral shape. The spiral arms are actually attributed to a roaming 'gravitational wave', where clumps of matter (stars or dust) group together temporarily, then separate again.

Answer 4

Well, maybe that and the fact Gaint Gas planets all seem to have rings around the middle seems to be a common theme.

Generally due to spin the equator has more mass and expells material from the equator. Material from the poles move inward twoards the equator.

A fact of rotation.

One of Newton's laws.

Less momentum at the poles more at the equator.

If these spheres didn't rotate they'd probably stay spheres.

Another phenomenon is the A-Bomb.

There's quite often a ring of smoke or plume coming out from the Mushrom moves upwards.

The blast starts spherical, mvoes upwards, a plume or ring comes out the middle of the sphere and the smoke rising upwards makes the stem of the mushroom.

Maybe that's the way God designed it all to happen.

Answer 5

If a galaxy is rotating as it forms, it tends to evolve into a spiral galaxy. Galaxy formation is still a very young science and not well understood. And as you say, there are spherical galaxies and irregular galaxies, most likely caused by collision with another galaxy.

If we look at distant galaxies, or in other words, younger galaxies 12 billion light years away, we see no spiral galaxies whatsoever, but instead we see such exotic objects like quasars, which are spherical.

Answer 6

Galaxies are available 3 considerable instructions in demand by using their visual charm: spirals, like the Milky way, are formed like pinwheels; irregulars have no discernible shape in any respect; and ellipticals are around- or oval-formed gadgets. Spirals and irregulars tend to be web pages of ongoing movie star-formation and for this reason incorporate youthful stars. Ellipticals, having finished their supply of sparkling gasoline, won't be able to form stars any further and incorporate quite often very previous stars. Spiral galaxies are a composite of stars and gasoline in a disk surrounding a appropriate bulge, it is extremely reminiscent of an elliptical galaxy, merely smaller. Waves interior the disk form the spiral arms and reason the gasoline to break down and form new stars. for this reason, the disk is wealthy in youthful stars. Older stars tend to be got here upon interior the bulge. Elliptical galaxies and the bulges of spirals have been the problem of various many years of observational and theoretical artwork. for some years, astronomers thought that the rotation value of those around movie star systems desperate besides the fact that if or not they could be around or oval formed, with the extra right this moment rotating ellipticals being the flattest. precise analyze of hundreds of ellipticals over the years now advise an distinctive photograph. Ellipticals and bulges are supported against their self-gravity, which might cause them to decrease, by using the random velocities of the celebs, especially very like the action of molecules in a warm gasoline. The distribution of stellar action determines the ideal shape of the galaxy, it is, besides the fact that if that's around, oblate, or very flattened.

Answer 7

Angular momentum must be conserved. Rotation will flatten a spherical object. With more mass in the equator of a flattened rotating object, objects in orbit will tend to move towards the plane of the equator. Jupiter and the Galilean moons are a good example.

Answer 8

It's because of the spin of the group of matter that condensed to form the galaxy. It's similar to what happens to pizza dough when it gets tossed in the air and rotated.

Answer 9

well

they aren't really that flat. I mean the tremendous distance gives them a unique look. If you were closer, it wouldn't look as flat, but they do certainly have an eleptical shape... Elipses are kind of like the number 7.

They turn up everywhere....

Answer 10

Spinning galaxies are flat because of centrifugal force. The force is strongest perpendicular to the axis in which is spins.