Just asking, but, recently I have been thinking of making several addons for the past and future of the solar system, and I have a couple questions. First, is there a good data source to take notes from when looking into making the addons, and how do you make textures for earth? i've seen quarior's earth 150m years ago addon, but I think the original has water in it, i was thinking of using celestia's alternate earth textures for the addons, can anyone help me on how to make/do stuff like this?