(I live tweet Cosmos every Sunday @ 8pm CST. For all of my Cosmos recaps, please click here)

This week's episode of Cosmos covered scientists such as Marie Tharp, who successfully mapped the ocean floor and its ridges, showing that the continents have been shifting over eons, Earth's land mass transformed from one super continent known as Pangaea to the familiar continent outlay that we know today.

The shifting had a significant effect on dead trees that lay deep in the rock of the planet. Eruptions caused poisonous gas to cover the Earth, freezing and heating up the planet and killing 90% of life. .

For more, check out the Storify of the live tweet below!