evidence: Earth than today, loomed large in the night sky. This cosmic quest takes us back in time to within moments of the Big Bang itself and retraces the events that created us, this place we call home and perhaps life elsewhere in the cosmos. Coming up tonight: the beginnings of planet Earth. [...] NEIL deGRASSE TYSON: What started as a giant ball of debris floating in space turned into Earth, but four and a half billion years ago, it wasn't exactly home sweet home. [...] NEIL deGRASSE TYSON: In its infancy, Earth was a primeval hell, a lifeless planet bombarded by massive asteroids and comets. The moon, much closer to Earth, loomed large in the sky. Instead of water, red hot lava streamed across the surface of our planet. Volcanoes spewed noxious gases into the primitive atmosphere. Scorched and battered, Earth was a planet under siege. Yet somehow, the world we call home emerged from these violent origins.