[His incredulity is greeted with a matter-of-fact tone that borders almost on nonchalance-- obviously, Sheryl recognizes that it was a harrowing moment for humanity, but it's in the history books for her. She knows that they survived and went on to spread through the galaxy.] It's pretty hard to believe, I know. The Zentradi orbital bombardment killed billions.

I'm not a hundred percent sure on the exact numbers, but by the end of the war, there were only a couple hundred million humans left on the planet.

So even after the Zentradi fleet turned on their masters and allied with us, we knew that we had to spread through the galaxy and find new home planets where we could live, just in case anything like that happened again-- with how close humanity came to extinction.

Makes sense to me, right?