According to Eureka Seven, to end existence, all you have to do is make too many things think at once... thus reaching the limit of questions and causing the universe to overload. Dewey, the Big Bad almost succeeds, by waking up the dormant aliens that have covered the earth's crust.
Though this seems to happen only in the anime, where the thoughts have mass (the trapar is made of the dreams of the dormant Coralian crust). In the manga, the limit of questions is never mentioned. The motivations of the Coralians are very different, too.
Anime First: An original anime project; a manga adaptation started a few months before the anime ended.
Creator Backlash: It's become public knowledge among fans that the original director Tomoki Kyoda planned for a more depressing ending to the anime before fan and staff reception forced him to change it. This may help to explain why almost all Eureka Seven media since seems aimed to undo the happy ending of the anime, with Eureka Seven Hi-Evolution ultimately retconning it out of canon in leu of a more depressing take on the franchise.
Enhanced on DVD: It is very notable upon watching the final episode that a lot of major changes are implemented to the ending to help it pop out, such as changing the colorful energy around the world the story takes place on (the Earth) from a muddy orange to a minty blue, and more clearly depicting the terrain of the planet changing with the Scub Corals leaving to indicate its true identity as Earth all along. However, a change that some people find disconcerting is the fact the original TV broadcast had a special end card showing Renton and Eureka as a couple back on Earth, with their children, proving unquestionably that they made it back home.
The Other Darrin: Bob Papenbrook, Ken-Goh's English voice actor, died during the dub's production in 2006 due to chronic lung complications, and was replaced by Kyle Hebert for the remainder of the series. Papenbrook's last recorded role as Ken-Goh before his death was "Memento Mori".
Studio Hop: At first, the North American home media releases were handled by Bandai Entertainment. Funimation acquired the rights shortly after Bandai Entertainment closed its doors.
This ain't Yuko Sanpei (Renton) and Kaori Nazuka's (Eureka) first time voicing the main couple, the first instance would be in UFO Baby where they voiced Kanata and Miyu respectively, this also doubles as Retroactive Recognition.