Scott Manley's video does a nice job trying to make some sense of the planet destroying creations in the
Star Wars movies, from the destruction of Alderaan to the latest film (Spoiler Alert!) that destroys multiple planets. His video,
How Much Power Do You Need to Destroy a Planet?, tosses in plenty of equations along the way discussing the destruction of Earth and Jupiter, but the bottom line is that the necessary energy and resulting destruction would fall outside of what Lucas and Disney have served up. Of course, no one can be surprised, but it is interesting to speculate.
However, the bottom line here is that you do not need a spectacular exploding planet to kill off a civilization. All you need to destroy is the outer 1 percent and nothing will survive. Why the overkill? But more to the point, we already have the ability to do to ourselves what the Empire did to others. That is a scary thought.
