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# Earth’s Core Should Be Impossible. A New State of Matter Explains It.
- URL: https://www.cascadepbs.org/show/pbs-space-time/episode/earths-core-should-be-impossible-a-new-state-of-matter-explains-it-hypcnq/
- Published: 2026-04-21T22:15:27.000Z
- Updated: 2026-04-21T23:01:04.000Z
- Description: Earth's core: solid or liquid? Yes — we know more about distant galaxies than our own interior.
- Author: Cascade PBS Staff
- Tags: PBS Space Time, Season 11, Episode 26, #ZZZ_Episode_08d9b92b-647d-495d-a777-cc38568f243a, #episode, #ZZZ_Show_ae70f836-13b6-4c9d-b61f-99f7b8bc29eb, #v1.16

Is Earth's core solid or liquid? Yes. Our planet's interior has been harder to study than the cosmos. We can send probes to the solar system's edge, and telescopes can see the most distant galaxies—but the 6,400km to Earth's center are opaque to light and beyond any drill. Our best tool is listening to distant earthquakes and piecing together how seismic waves bounce through the interior.