Final answer:
An excess of angular momentum might prevent a solar nebula from collapsing into a proper disk, hindering planet formation, while zero angular momentum would preclude the formation of a planetary disk altogether. The conservation of angular momentum played a crucial role in forming the rotational disk structure of our solar system from which the planets accreted.
Step-by-step explanation:
The possibility of planet formation in a solar nebula with much higher angular momentum would depend on several factors, including the distribution of that momentum and the efficiency of processes like friction and collisions within the nebula that can redistribute angular momentum. If angular momentum were too high, the centrifugal forces might prevent the collapse of material into a disk and inhibit planet formation. Conversely, with zero angular momentum, the nebula would lack the necessary rotational movement to form a disk, and material would likely fall directly into the central object, possibly preventing the formation of a planetary system.
The process of planet formation in our solar system and others is deeply rooted in the conservation of angular momentum, as seen with our own solar nebula, which contracted from an interstellar cloud of gas and dust. As the nebula collapsed, its rotation speed increased to conserve angular momentum, forming a disk-shaped structure from which the planets eventually accreted.
Therefore, an excess or complete lack of angular momentum would significantly alter the dynamics of the solar nebula and likely result in a very different kind of planetary system or even the absence of one.