outer space

The universe is so much bigger than what people can see. Visible matter — the ground, the Sun, the screen you're reading this on — makes up only about 4 or 5 percent of our known universe. Dark matter makes up much more of the universe. It's all around us even though we can't see it. So what is it? What's it made out of? How do we even know it exists? Host Emily Kwong and Rebecca Ramirez try to find out with the help of astrophysicist Priyamvada Natarajan.

This episode is part of our series Space Camp, all about the weird and mysterious depths of our universe. Check out the full series: https://www.npr.org/spacecamp.

Our team would love to hear your episode ideas. Email us at shortwave@npr.org.

Before the '3 Body Problem' became a bestselling book and a smash TV show ... it was a physics concept, with big implications for how we understand planetary orbits. In this episode, we learn about the science behind the screen. Plus, why it's plausible a nearby, mysterious planet could hold life.

This story is part of Short Wave's Space Camp series about all the weird, wonderful things happening in the universe —check out the full series.

Curious about other science behind the things you love? Email us at shortwave@npr.org.

Though Pluto has formally been considered a dwarf planet for almost two decades, it still has many lessons left for planetary scientists — including hints about how the solar system formed.

Pluto hasn't been a planet for almost 20 years. In the early 2000s, scientists discovered several objects of a similar size to Pluto. So, during the summer of 2006, members of the International Astronomical Union convened in Prague to reconsider what counts as a planet in our solar system. IAU members decided that there were three criteria to be a planet — and Pluto did meet all of them.

But planetary scientist Wladymir Lyra says that even though it was downgraded to a dwarf planet, Pluto still has much to teach us about planet formation. This episode, he also lays out his case for Pluto — and many other objects in the solar system — to be considered a planet.

This episode is part of Short Wave's space camp series about all the weird, wonderful things happening in the universe. Check out the full series.

Questions about the state of our universe or smaller happenings here on planet Earth? Email us at shortwave@npr.org — we'd love to consider it for a future episode!