What is the connection between eureka seven and eureka seven ao?

Answer 1

Fact: ao is the son of eureka (and probably Renton.. but this is not yet shown/confirmed in the series).

Watch out, some "spoilers" up to episode 12, and speculation ahead:

it seems the story of ao is on a different planet/reality than the original eureka seven series. In Eureka seven AO there is the planet earth almost as we know it in real life today. With Amerika, Japan, etc. All these country's don't exist in the first eureka seven series.

In episode 12 especially there are a few hints that the 2 worlds are linked.

There are a few people on the internet that are speculating that ao is in the world/other dimension that is mentioned at the end of de eureka seven series. At the end of the first series Nirvash tells Eureka and Renton that a part of the scub coral and all the humans that have combined with the scubcoral (or something like that) will go to another world/dimension to live there. This is because of the theorie called limit of questions(as it is called in the English version) or called limit of life (in japanese). This is the theory that too much sentient life in a given space will collapse reality. When the scubcoral woke up and exceded the limit of life/limit of questions they saw this other wordl/reality.