How possible is Star Wars Part II: Galactic empires aren’t built in a day

Star Wars and Star Trek are often compared to each other. After all, they both center on largely human characters who travel from planet to planet, each one surprisingly livable and often full of plants and animals, not unlike those on Earth.

The big difference is that in Star Trek, the civilizations are often solar-system or planetary based, each with their own form of government. In Star Wars, there’s a single entity — the Empire — that acts as the government over the entire galaxy.

Lots of planets, relatively few good options

A conservative estimate of the number of planets in the Milky Way is about 100 billion. That’s a lot, but think about this: There’s 100 billion galaxies in the observable universe which means there’s potentially 1e22 or 10,000,000,000,000,000,000,000 planets out there! I’m not even sure what -illion that is. I’m sure that didn’t bother Han Solo, though.

This means there’s almost unlimited potential homes for life out there. It also means that Star Wars might not be too far off when it comes to the whole idea of a galactic empire full of humans and intelligent nonhumans.

It seems that we’re discovering new exoplanets (planets outside of our solar system) every day now. Of those planets found, the majority are gas giants and would never house Earth-like life. There are also some rocky planets out there, but many of them are much bigger than Earth. Bigger often, but not always, means greater mass. Greater mass means more gravity. A planet twice the size of Earth, for example, would be 2g (twice that of Earth’s gravity). That might not sound like a big deal; you’d essentially weigh twice as much as you do now. A 200-pound man would suddenly weigh 400, a heck of an adjustment. You’d also see your body age faster as exposure to heavier gravity causes your features to droop. Now imagine 3g or 4g … which would be fatal within a few days.

Then there are rocky planets on the other end of the spectrum, which are smaller than Earth with less than 1g. Mars is a prime…