What if the Aztec Empire had survived into the space age? They would rule many planets! Different colors of blood would run down the great temple at Tenochtitlan. All the major temples would be in space because this is as close to the gods as one could get.
What an exciting scenario! Hope you all like it.
There are several challenges involved in getting the Aztecs into space, as cool as the idea sounds. You have to keep the Europeans, or at least their diseases out. Discovery of the Americas could only be delayed so long with economic pressures in Europe and advancing naval technology such as caravels. The Aztecs also had powerful rivals in Mexico to deal with such as Tlaxcala, which Cortez used to his advantage in real life. That said, Cortez was extremely lucky to get as far as he did, so perhaps the Aztecs could survive an initial disease outbreak and develop resistances in the future. And of course, there's the issue of developing interstellar flight to make the green blood spill in Tenochtitlán. . .
If the Aztecs were extremely lucky and could hold out for long enough, I can see them making technological strides. They were known for having universal education, better sanitation than Europe, and producing much as much literature as the ancient Greeks.
EDIT: I would look at the Before 1900, After 1900, and Future History as more of "How do I get this to happen?" approaches, and Alien Space Bats as "What happens after this?" People seem to use Alien Space Bats as a criticism here, but it can make for good fantasy and science fiction scenarios, which is what you're going for here. Just take care not to have your topic drowned out by the fanfiction in the ASB forum.
