Physicist Marius Millot investigates the intimate atomic worlds of elements in order to understand the inner secrets of the largest planets in our solar system. Jupiter and its fellow gas giants Uranus, Neptune and Saturn are comprised mostly of the lightest element, hydrogen, with a dab of helium, heavier elements, and more complex molecules. But researchers want to know what lurks at the planet’s core, under all that cloud. It isn’t clear that Jupiter has a surface to stand on that is at all like Earth’s—assuming anything could stand up under pressure approaching 100 million Earth atmospheres. That pressure may turn the depths into a hot, dense soup.

Millot can’t visit the Jupiter’s interior, but he can simulate some of its conditions here on Earth. As a researcher at Lawrence Livermore National Laboratory in California, he gets to play with giant lasers designed to explore atomic fusion. When the 192 lasers of at the National Ignition Facility focus on a single point, they can reproduce the unimaginably intense pressures in the interiors of planets, or even stars.

With diamond as an anvil, Millot and his colleagues have used the lasers to squeeze liquid hydrogen so tightly that it turns shiny, hinting that hydrogen near the center of the big planets may be a flowing metallic liquid, and perhaps the source of Jupiter’s mighty magnetic field. Millot explains how the center of Jupiter might just be a mushy blob in this episode of Third Pod from the Sun.

This episode was produced by Liza Lester and mixed by Kayla Surrey.