here is the complete story on Starbucks Viper as i found on another website
Here is the story. The Viper being Cylon was able to jump, this jump is what Apollo thought was an explosion. Evedently when the Viper was deep in the Nebula Cloud it was forced to jump to avoid its own destruction. After a relatively short jump, the Viper limped to Earth badly damage with Starbuck in the cockpit unconscience. Starbuck was kept unconscience until she was revived in a new copy of the Viper which then returned to the fleet.
Unfortunatelyly the other Cylons tracked Starbucks Viper to Earth via the heavy raider which Starbuck originally went after in the cloud. The Raider being so close to the Viper was able to jump along with it. The Cylons, thinking Earth was inhabited by Humans, then blew the crap out of it. This happened between the time Starbuck visited Earth and the time the Galactica got there. Earth however was populated not by humans, but by copies of the final five who had been hiddin on Earth and were suppose to never be discovered. These final five had become pacifist and were unable to defend against the unexpected attack. Now millions of ultra advanced Centurians and the few thousand original five copies remaining are arming and creating weapons of incredible destruction. This all happening on a lesser damaged continent of Earth which will soon revolve to face the colonial fleet in Orbit.
These Cylons will capture Galactica and return to the Colonies in one jump. Then seeking revenge on the Cylons who destroyed Earth the Final five will end the rein of the originals. The centurians evetually destroy all human looking Cylons, including the final five, under the command of Baltar. They see Baltar as their true leader, as he is the only person who ever told a Centurian model that they were Gods creatures too. Baltar also turns out to be a clone of the original Baltar that died in the first nuclear attack. Six had rendered the first Baltar unconscience to insert a scanner into his brain, his thoughts could then be directly sent to a cloned replacement. Unfortunately when Six and Batar died in the Nuclear Attack their thought patterns merged while being transmitted to the resurrection ship. This is why Baltar hears Sixs' thoughts and vice versa. Baltar is not the only Human the Cylons were able to clone, and not the only one currently in the fleet. Speculation is that Adamas oldest son will make a return.
After all this,
The Colonials return to re-populate the colonies. The Centurians take Baltar and one copy of Caprica Six and head for a planet called Senganee. The Cylons will then re-evolve, the colonies will re-populate and after time has erased the story, the whole Cylon Human conflict, will happen again as it had happened before.
Starbuck as it turns out was the first Human/Cylon hybrid. She is the daughter of a Saul Tigh model and a woman named Zuzu Petals. Starbuck brought death to her people, both Cylon and Human, by bringing them together when they were meant to be forever apart.