Many of science fiction's greatest novels are written in third-person omniscient. And this should come as no surprise, because nothing lets you depict a complex situation full of people (and creatures) with their own points of view, like a narrator who can view the whole scene from outside.
But many, many writing teachers will tell you to avoid third-person omniscient at all costs. They'll break out the pain sticks. Why is this? Because third person omnisicent is so freaking easy to mess up. And if you crash and burn with an omniscient narrator, you leave an extra-large crater. How can you write an omniscient narrator without being omniscient yourself?