A series in which scientists theorize about how the end of the world may occur begins with speculation about a rogue planet crashing into Earth.
Gamma-ray bursts are considered as an end-of-the-world scenario.
Scientists theorize about how volcanoes may decimate the planet.
The possibility of a global killer asteroid is examined.
A study of how methane explosions that took place underwater might have been responsible for the extinction of the dinosaurs.
A study of a possible mega-tsunami that could be triggered by a volcanic eruption.