- #36
DaveC426913
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Well, there are theories that posit a rotating universe...
Chronos said:the tiniest of imbalances [like the gravity of the nearest star] will impart a preferred direction of travel.
Nyxie said:This and an understanding of angular momentum sum it up based on textbooks/professors I know.
Also, think about why this spinning doesn't happen as much when you throw something on Earth. In space where we're far from strong gravitational influences (like stronger pull of gravity on Earth's surface) smaller gravitational forces have a greater effect since they aren't overpowered by larger ones.
An astronaut throwing a pencil won't give it a perfectly linear momentum in the first place anyway, since there's some curvature in the movement of the arm and it's reaaally unlikely they'll throw in a perfect straight line.
DaveC426913 said:As the dust and gas move under the influnece of their mutual gravity, they will fall toward each other. Their initial inertia will be preserved, so that, by the time they collect into clumps and solar systems, the clumps will have some of that spin, even while the whole system orbits.
Nyxie said:OK, that explains things. But what about the astronaut and the pencil? Its inertia after being released/thrown is primarily determined by how it's thrown, right? so what else is it determined by?