Abby: Right. It's also one of the things that owes a bit of its success to the original Cosmos series. Like Tyson, Sagan had a few overarching themes that surfaced again and again.

Danielle: But before we delve more into the climate change stuff, I think we should spend some time on what Tyson discussed in the first half of the episode. Like those massive, alligator-sized, oxygen-fueled centipedes, and the subterranean forests that trapped carbon within the Earth. I love when Cosmos focuses on this planet, and the drastically different forms it has taken -- and will take.

Abby: It's about perspective. While there's an easy sense of wonder that comes from, say, watching Tyson's ship imagine what it will look like when our entire galaxy collides with a neighbor, our day-to-day perception of the cosmos is Earth. And we know it less than we assume, as is becoming more and more clear as the episodes continue. At one point, Tyson mentions that fewer humans have been down to the Marianas Trench on the ocean floor of our own planet than have been to the Moon.

Danielle: I’m so glad that another female scientist, Marie Tharp, was mentioned in this episode -- with just the right amount of acknowledgement that she’s a woman. Last week we took issue with how the “women’s” episode played out, but this time I think there was a pretty fair balance. Tyson talked about Tharp as an influential scientist who happens to be a woman, but also as one who should be recognized as a scientist who overcame sexism to contribute to her field.

Thanks to Marie Tharp, we were at last ready to read the autobiography of Earth itself. #WatchingCosmos #cosmos pic.twitter.com/G7RZpH3RGI — COSMOS (@COSMOSonTV) May 5, 2014

Abby: Yes agreed. It seems to me that Cosmos has been better about applying the social commentary it made on sexism and social bias in science than they were at articulating it last week. In this episode, Tyson made his point very clear when he briefly placed the scientific method in tension with the scientists who practice it, using Tharp as an example. The method, he said, is at its heart a way to reduce human error, blindness, and bias in scientific work as much as possible. But it's hardly instant or complete, which is why every single episode of this show has clearly featured (and sometimes criticized and commented upon) the social context in which discoveries that have propelled us closer to an understanding of the world were made. Often, that human propensity for error or willful ignorance has come from external, powerful institutions, like the Roman Catholic church at its peak of influence. But with Tharp, the call was coming from inside the house.

Danielle: Definitely. Speaking of challenges to female scientists and awkward segues, I find life in the deep sea to be totally fascinating. As crazy as it is to think about the depth and reach of the cosmos, it’s even crazier to think about how much of the earth is alien to us. We share a planet with animals that don’t need sunlight to live and survive off of bacteria spewing from hydrothermal vents.

The inhospitality of the deep sea is yet another reminder of how foolish it is for us to pump fossil fuels into our air -- not only is Earth the only place in the known universe that our kind could survive, but most of Earth is also hostile to human kind. When you think about, as Tyson instructed us to do throughout the episode, how unlikely it is for us to have survived thus far and how tiny our swathe of this planet practically is, our willingness to throw it all away seems even more stupid than usual. I hope the EPA was watching last night.