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.Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy