I've been watching a quite a bit of Star Trek (The Original Series) recently on Netflix and I've noticed something. The USS Enterprise sure does visit a lot of planets that are "just like Earth". The producers of the show did this for a number of reasons but mainly because it was cheap. Why spend a ton of money creating an alien landscape or city when you can just film on the studio backlot or on a location in sunny southern California? All you have to do is throw in some lines where the crew marvels at finding a planet that's just like Earth. Something like this scene from The Paradise Syndrome...
MCCOY: Look at those pine trees.
KIRK: And that lake.
MCCOY: I swear that's honeysuckle I smell.
KIRK: I swear that's a little orange blossom thrown in. It's unbelievable. Growth exactly like that of Earth on a planet half a galaxy away. What are the odds on such duplication?
SPOCK: Astronomical, Captain. The relative size, age and composition of this planet makes it highly improbable that it would evolve similarly to Earth in any way.
And there you have it. We can then film our alien planet scenes near the Franklin Reservoir just north of Los Angeles. Just hope you don't bump into Andy and Opie going fishing. That reservoir also served as the filming location for the lake near Mayberry in the Andy Griffith show. The episodes Miri & City of the Edge of Forever were actually shot on the same backlot as the Andy Griffith show! You can see Kirk and crew walk right past Andy's courthouse, Floyd's Barber Shop, etc. Here's a whole web site dedicated to this fact.
Convenience isn't the only reason the writer's used Earth like planets in Star Trek. Roddenberry wanted to use Star Trek to tell morality stories. He felt that science fiction is at its best when it holds a mirror up to society and teaches us a lesson. So whenever he wanted to make a political statement about the world we live in-- the Enterprise would just go visit a world like ours to tell the story.
But it seems silly to think that there could be so many other Earth like planets in the universe, right? Apparently not! According to a recent article on io9.com, There might be 2 million planets similar to Earth in our galaxy alone! Here is a quick excerpt from the article:
Based on the data from [NASA's Kepler probe], the JPL scientists estimated that 1.4 to 2.7 percent of all stars with the same basic properties as our Sun are home to Earth-like planets. That means a planet between 0.8 and two times the mass of Earth that lies within the habitable zone of its star. When you total up the amount of sun-like stars in the galaxy, that gives you two billion stars. And, of the hundred or so sun-like stars within a few dozen light-years of Earth, at least two of them should be home to habitable worlds.
JPL researcher Joseph Catanzarite points out just how many Earth-like planets there might really be:
"This means there are a lot of Earth analogs out there - two billion in the Milky Way galaxy. With that large a number, there's a good chance life and maybe even intelligent life might exist on some of those planets. And that's just our galaxy alone - there are 50 billion other galaxies."
So there! The fact that the Enterprise bumps into Earth like planets all the time is suddenly not so far fetched! As Spock would say, that's fascinating. :)
