Venus is the hottest, scariest planet in the solar system, but billions of years ago it may have been a lot like Earth, complete with an ocean of water. So, what killed Venus? And could Earth be next?

For more, go to http://vox.com/unexplainable

It’s a great place to view show transcripts and read more about the topics on our show.

Also, email us! unexplainable@vox.com

We read every email.

Support Unexplainable by making a financial contribution to Vox! bit.ly/givepodcasts

Learn more about your ad choices. Visit podcastchoices.com/adchoices