Socotra Island has been called the most alien-looking place on Earth, and with good reason. Sitting off the coast of Yemen in the Arabian Sea, it’s home to plants and landscapes found nowhere else.

In space, no one can hear you scream, but they can sure hear you scratching your head as you try to make sense of the sprawling “Alien” universe. While Ridley Scott’s 1979 haunted-house-in-the-cosmos ...