Soran needs to get to the Nexus. There is a planet that the Nexus will miss unless the sun is destroyed, in which case the Nexus will fly right through the planet. So Soran camps out on that planet and tries to destroy the sun. Before he blows up the sun, the nexus is seen flying through the sky BELOW the clouds! This is just not possible. On the enterprise, Picard and Data study holographic charts that clearly show how huge the Nexus is, and how far away from any clouds the Nexus will miss the planet by.