Exploring the real-life Death Stars in the cosmos that could snuff out Earth without much effort; the science of the destructive power behind six of the deadliest stars; vampire stars; supernovas; rogue stars.

Life once existed on Mars, but a series of devastating mass extinctions have made present-day life nearly impossible. The latest science shows how Martian life keeps bouncing back as it transforms from a watery world like Earth into a desert planet.