I ain't got much time to figure it out, thus i won't be able to help you much in the understanding of how it is done. But i recommand to show only animated objects in the timeline and check independant timelines individually. Actually, there are many "undertimelines", that are checkboxed as independant timelines in a large tree of labels and key points, played via button events.
"Infant timelines" (such as planets rotations) are housed in individual layers and are ruled by "Parent timelines" (such as "Content Group"). Then, the buttons, images and others are hotspots that start and stop "undertimelines".
See the screenshot for further ideas about how it can be done. Don't forget to activate the right timeline to see how it works, ant then check out the "buttons" and see how they are used as switches to the independant timelines actions. Everything seems to start with the "Sun Location" group and the "Content Group" timeline (if you do not activate this timeline, you cannot navigate and see animations through the timeline).