Once upon a time, there were no anuses. These ingenious organs allowed our primordial ancestors to grow bigger and more complex, but scientists still don’t understand how they evolved. And they’re still grasping at a mystery that literally surrounds it: Why is the human butt so big?For more go to http://vox.com/unexplainableIt's a great place to sign up for our newsletter, view show transcripts, and read more about the topics on our show.Also email us! unexplainable@vox.comWe 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

This common chronic condition — where tissue similar to what grows inside the uterus grows elsewhere in the body — is barely understood. So why is a condition so prevalent and painful still so unknown? It has a lot to do with who gets to ask research questions.Correction, August 18: An earlier version of this episode implied that the tissue involved in endometriosis is the same as the endometrium, which lines the uterus. It is similar tissue, but not identical.For more, go to http://vox.com/unexplainableIt’s a great place to sign up for our newsletter, view show transcripts, and read more about the topics on our show.Also, email us! unexplainable@vox.comWe read every email.Support Unexplainable by making a financial contribution to bit.ly/givepodcasts Learn more about your ad choices. Visit podcastchoices.com/adchoices

Two scientists. A billion-dollar wager. One unanswered question: Is the first human who will live to 150 already alive? The technology to make that happen may already be in development. But if it works, there will be new, unsettling questions for humankind to answer.For more, go to http://vox.com/unexplainableIt’s a great place to sign up for our newsletter, view show transcripts, and read more about the topics on our show.Also, email us! unexplainable@vox.comWe 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

Earlier this year, Nicole Yamase explored the bottom of the Challenger Deep, the deepest place in the ocean, where few people have ever been. The rest of the seafloor is almost as mysterious — 80 percent remains unmapped — but the few glimpses scientists have gotten have completely revolutionized our understanding of the planet.For more, go to http://vox.com/unexplainableIt’s a great place to sign up for our newsletter, view show transcripts, and read more about the topics on our show.Also, email us! unexplainable@vox.comWe 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

8 minutes, 24 seconds. That’s the average amount of warning time people get before a tornado touches down. To do better, and to understand tornadoes, scientists need to confront more of these storms, head on.For a clean version of this episode and more, go to http://vox.com/unexplainableIt’s a great place to sign up for our newsletter, view show transcripts, and read more about the topics on our show.Also, email us! unexplainable@vox.comWe 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

Astronauts left something on the moon that could help unlock the origins of life itself.For more, go to http://vox.com/unexplainableIt’s a great place to sign up for our newsletter, view show transcripts, and read more about the topics on our show.Also, email us! unexplainable@vox.comWe read every email.We are conducting an audience survey to better serve you. It takes about five minutes, and it really helps out the show. Please take our survey here: vox.com/surveySupport Unexplainable by making a financial contribution to Vox! bit.ly/givepodcasts Learn more about your ad choices. Visit podcastchoices.com/adchoices

An accidental discovery on a nighttime walk led one scientist and his team to wonder: How many mammals glow under ultraviolet light? The list keeps growing, but scientists still aren’t sure why these furry creatures glow.For more, go to http://vox.com/unexplainableIt’s a great place to sign up for our newsletter, view show transcripts, and read more about the topics on our show.Email us at unexplainable@vox.com. We read every email!Also, we are conducting an audience survey to better serve you. It takes about five minutes, and it really helps out the show. Please take our survey here: vox.com/surveySupport Unexplainable by making a financial contribution to Vox! bit.ly/givepodcasts Learn more about your ad choices. Visit podcastchoices.com/adchoices

The podcast explores how Henrietta Leavitt's discovery revolutionized astronomers' understanding of the universe, from measuring star distances to the universe's impending end. It highlights the enigmatic life of Leavitt and the role of women in early astronomy, leading to revelations about the universe's expansion and dark energy.

As part of a massive new global tracking project, scientists are monitoring animals from a receiver on the International Space Station, mapping the incredible, previously unknown journeys that animals undertake. They’re beginning to tackle questions like how far do animals actually move? And how in the world do they know where they’re going? Learn more about your ad choices. Visit podcastchoices.com/adchoices

These worms are fast, they’re mysterious, and they’re quickly changing North American ecosystems. How worried should we be about global worming?For more, go to http://vox.com/unexplainableIt’s a great place to sign up for our newsletter, view show transcripts, and read more about the topics on our show.Also, email us! unexplainable@vox.comWe 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