That’s because all sci-fi alien species are monocultures
And all sci-fi planets have exactly one type of terrain/biome.
You got desert planets, swamp planets, forest planets, ice planets, hell – even city planets … but you never see any planet that has similar diversity to Earth … or even similar diversity to California. In sci-fi, every planet looks the same across its entire surface.
Desert planets and, to a lesser extent, ice planets, are actually pretty realistic. We have more desert planets in our own star system than Earth-like planets. Of course, they’re not habitable like sci-fi desert planets.
And all sci-fi planets have exactly one type of terrain/biome.
You got desert planets, swamp planets, forest planets, ice planets, hell – even city planets … but you never see any planet that has similar diversity to Earth … or even similar diversity to California. In sci-fi, every planet looks the same across its entire surface.
Desert planets and, to a lesser extent, ice planets, are actually pretty realistic. We have more desert planets in our own star system than Earth-like planets. Of course, they’re not habitable like sci-fi desert planets.