What’s the Most Likely Source for Interstellar Travel?

I’m currently reading an exceptional sci-fi book that I’ll discuss in a day or two. For now, I want to focus on a question raised by the book: What is the most likely source for interstellar travel?

Various sci-fi books and movies have suggested these sources:

  • Humans figure it out
  • Artificial intelligence cracks the code
  • Aliens teach us the way

And, of course, there’s the least exciting option: We never figure it out, and we’re stuck slowly traveling within our solar system.

If interstellar travel ever happens, I lean slightly towards the AI theory. We’ve done a pretty good job of getting computers to think independently, but we’re much farther behind when it comes to far-space travel. We’re still figuring out propulsion–we’re going to need a lot more than a few rockets to transport humans across the great expanse.

The alien theory is fun and easy…almost too easy. Though it does echo certain elements of Earth’s history, wherein a vastly advanced culture discovers an much older, indigenous culture, and their level of technology instantly advances by hundreds of years.

What do you think is the most likely source?