Five refugees from an alien planet are traveling to escape some cataclysmic event (not important here). I need them to land on Earth, 65 million years ago. (At this point in time, their technology is, say, 10 millennia ahead of modern human technology.)

The problem is, 65 million years ago, there are only dinosaurs. (The landing of the refugees caused the extinction. It's complicated.) The aliens don't have the technology to see 65 million years into the future (or really, any time into the future). They also do not have the technology allowing them to predict that any sentient life will evolve at any time past their landing.

We want them to land on a planet that will evolve sentient life (or already has it. The reason is not important.) I need them to be on Earth, because the main characters are, well, humans on Earth. However, there are other planets (and probably closer ones than Earth, since the planet of origin is quite far from Earth) which already have developed known sentient life.

What's a plausible reason for them to land on Earth? (Chance is a cheap answer, so I'm not accepting that as an answer.)

  • $\begingroup$ Hi Ian Ng, welcome to Woldbuilding! Do aliens want to land on already occupied planet, or otherwise nice planet with dinosaurs would suit them just fine? $\endgroup$ – Alexander Jul 18 '18 at 0:30
  • $\begingroup$ @Alexander Any nice planet that can sustain life (main evidence of this is if the planet already does) works. However, for obvious writing reasons, I need this to be on Earth. $\endgroup$ – Ian Ng Jul 18 '18 at 0:32
  • $\begingroup$ So, perhaps your aliens really liked Earth's climate 65 million years ago and didn't want any other sentient species to spoil this paradise. $\endgroup$ – Alexander Jul 18 '18 at 0:35
  • $\begingroup$ @Alexander So basically, we just assume no other planet has a climate that they see as favorable? Sounds good. $\endgroup$ – Ian Ng Jul 18 '18 at 0:37
  • $\begingroup$ They chose earth because they saw it as perfect for kicking off intelligent life that was different to theirs. Earths biodiversity at the time gave this the best chance for success overall as there were a lot of dna and species ready to be tampered with. Large biodiversity may even be required for intelligent life to evolve overall. $\endgroup$ – Seserous Jul 18 '18 at 0:58

While you say you won't accept chance as an answer, it really is as good as any. To quote an influential book (wherein another group of aliens ended up on prehistoric Earth),

Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space.

So if your aliens can traverse the distance between stars in their lifetimes, they're already bending or breaking some fairly major laws (as we understand physics), so the cataclysmic event destroying their home planet could cause a four-dimensional space wedgie that screws with their Zeta-drive, tossing them out of ptilospace right next to an insignificant little blue-green planet that happens to support life. Which is fortunate, as their Zeta-drive has failed.

(It can even fail in a way that produces a ghastly amount of radiation, neatly dealing with the majority of the dinosaur problem.)

  • $\begingroup$ Nice. I'm actually going to ignore time dilation and the like, so screw relativity, I guess. The refugees are also incredibly powerful (this has to do with why they were able to escape), like, survive-hundreds-of-millions-of-years powerful. But that's actually a really good explanation, I might use it. Thanks! $\endgroup$ – Ian Ng Jul 18 '18 at 0:55
  • $\begingroup$ A 4D space wedgie is oddly more terrifying than, say, a super nova going off in your face or being spaghettified by a blackhole. $\endgroup$ – ironduke97 Jul 18 '18 at 2:19

The fact that Earth is less interesting compared to the other planets could be part of the reason. A common source of calamity and refugees on Earth is war. These aliens might be looking for a place to hide, and by going to a more remote place, they make it harder to be found.

Alternatively, they may wish to avoid native sentient life. In a refugee situation, they may lack a lot of the technology they would need should the natives perceive them as a threat and try to kill them. They may have ethical reasons not to interfere with the natives. They may even just want to avoid potential competition in their new home.

Finally, the exact nature of the calamity may make Earth better. Maybe the nitrogen in its atmosphere kills a plague, or its location in the galaxy makes it impossible (or unlikely) for the threat to spread to it millions of years later. You'd have to come up with this type of answer, naturally.


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