Why did the solar nebula flatten into a disk?

Question

Why did the solar nebula flatten into a disk?
The interstellar cloud from which the solar nebula formed was originally somewhat flat.
As the nebula cooled, the gas and dust settled onto a disk.
It flattened as a natural consequence of collisions between particles in the nebula, changing random motions into more orderly ones.
The force of gravity pulled the material downward into a flat disk.

Answer 1

As the gas cloud coalesced particles were being pulled towards the center of gravity (what will become the star). The gas cloud is also rotating. Centripetal forces from rotation are then trying to throw material away from the center of gravity. The stable configuration for this is for the mass away from the center of gravity to settle into a plane perpendicular to the axis of rotation. So, the cloud flattens out into a plane perpendicular to the axis of the cloud's rotation.



EDIT: "none of those answered my question. this is a mutiple choice question. I just for got to mark the answers A, B, C, D."



Honestly none of your choices are correct.



"A" is right out.



"B" is right out.



"C" not right



"D" not close



Guess "D" is closest if you must but your teacher should be fired. The answers are very wrong.



Gravity in the initial cloud will not pull into a flattened disk. Matter will want to clump but it will clump randomly in different areas, not on a plane (except by some insanely remote chance).



Collisions will not randomly flatten it either. Collisions will be random and pushing in all directions.



Cooling gas is just less energetic gas...it won't flatten.



Gravity *will* pull towards the center however where the most stuff is (the yet-to-be-star). Angular momentum is conserved however and the whole system will spin. As it spins the stuff further out will want to fly away. Gravity keeps this from happening so it all settles into an orbit and the stable orbit is perpendicular to the axis of rotation.



Hell, we see this when a guy throws pizza dough in the air and spins it. The dough flattens out into a circle perpendicular to the axis of spin.

Answer 2

Says Who?

On the One Hand,

There is a similar relationship with our planets, residing mostly in the same orbital plane.

On the Other Hand,

There is no way the nebula started as a primordial disk with such resolution. It probably was manipulated later to form the disk.

On the Gripping Hand,

There is a lot of speculation here which you state as fact. There is no way we can be convinced the nebula was formed without a lot more thought. For instance, we are 'seeing' proto-planets around other stars which we have no ability to 'see' as defined by the astronomy we use, yet they are visible.

Answer 3

The last choice, "The force of gravity pulled the material downward into a flat disk." is the correct choice.

This is the event that reheated the disk.

Answer 4

its b, it flattened as a natural consequence of collisions between particles in the spinning nebula....



I took the same quiz in astronomy

Answer 5

The answer is actually C. The Best Answer told you D and that is completely wrong and you will get 0 points for that answer every time as it is the answer I have guessed on two quizzes in a row and got the answer wrong so I have learned by now.