CalicosineSo my theory that it's the White Whale may be partially correct. I couldn't have guessed that they would rebuild it with the Ma-non ship and have it be the White Whale 2 or that they'd leave Mira because of de-materialization, so my thought was that it was the original White Whale and the restored Earth was Mira, which means it's not fully correct but I like the way they handled it better. We know where the Conduit is, too.
My thinking was "a bright, blue light going that fast at that angle toward that planet can only be one thing we're aware of: the White Whale. KOS-MOS was only floating in space and was at the very least in power save mode, and however Elma arrived (can't remember if we knew she had the Ares at the time) would probably not be that bright from this distance."
I do wonder if the Logos Core was used to make Ares in combination with the Conduit, considering there's a purple Core shown at the end, Al keeps calling Ares "he", Aegis Cores can record lots of data, and there's an artificial intelligence system inside Ares that helped Al filter through the data in the void space.