It is a big universe after all

Light and Matter has some sage observations about the lack of proper magnitudes in SF movies and television.

the sad truth is that most people — even many highly educated people — never really develop a gut feeling for the wildly varying magnitudes of numbers, or an ability to reason about them.

A good example is the way some science fiction writers try to compress cosmic scales of time, space, and energy to make them conform to the human experience. The basic motivation seems to be a lack of creativity. We’re all familiar with the earthbound tropes represented by Horatio Hornblower, Captain Hook, or Stanley and Livingstone, so why not just translate all those tired old storylines into outer space?

Well, there are a lot of good reasons why not. Let’s start with energy scales. The U.S.S. Enterprise of Star Trek fame is about the same size and tonnage as the Queen Elizabeth 2, so if it was moving at half the speed of light, its kinetic energy would be something like 1024 joules. That’s equivalent to about a hundred billion Saturn V rockets, or about a thousand times the total megatonnage of the world’s nuclear arsenals. In other words, the Enterprise is the ultimate weapon of mass destruction. If you accidentally crash it into a planet (didn’t that happen in one of the movies?), it’s more than enough to destroy everything alive.

If only science fiction movie makers would pay more attention to respectable astronomers, they would grasp the scale of the universe …. or to Yakko!