Filmmaker Werner Herzog and volcanologist Clive Oppenheimer team up again for Fireball: Visitors from Darker Worlds, which stands as something of a companion piece to their previous collaboration, 2016’s Into the Inferno. Where the earlier film followed them on a globetrotting game of hopscotch to gaze into the hellmouth abyss of active volcanoes (and obsess over them with a motley crew of visionary scientists), their latest finds them looking to the skies for trailblazers of a completely different sort.