How many galaxies and solar systems within each galaxy does conventional science believe exist?
And how many exist in the Stargate universe?
So far I think we have the Milky Way, the Pegasus, the Ida and the galaxy of the Ori. And if there are several thousand solar systems in each, of which say 10% have intelligent life (including of course Unas and Wraith and the like), that would account for what, about a couple of thousand inhabited worlds per galaxy?
If I remember correctly, Teal'c once said they had visited 150 some planets, so that could account for only about 25% of all inhabited planets in the Milky Way, correct?
Now these numbers would also have to take into account many planets who either did not have stargates from the Ancients or who had no contact with Earth, the goa'uld or each other. If I recall correctly the Aschen had never encountered the goa'uld.
Even in the Pegasus galaxy there must have been many planets who never encountered the Wraith (lucky them!) and same goes for the galaxy of the Ori before they were destroyed.
Speaking of Ancients, I can never get straight their story properly. Did they originate in their own galaxy and get forced to travel to the Milky Way because of the Wraith, and of all the possible planets they settled on Earth? Then they returned to their galaxy while leaving behind stargates on Earth and elsewhere as well as inhabitants? And did they establish their own human colonies throughout all the galaxies of the universe, or did humans develop independently in the universe without the Ancients? Who did the Ancients believe created themselves if they were the very first humanoids? Did they beleive in God as the Creator?