How do scientists know what the core of the Earth is made of, even though we’ve never drilled anywhere near that deep?

Question

How do scientists know what the core of the Earth is made of, even though we’ve never drilled anywhere near that deep?

In: Planetary Science

Answer 1

Big earthquakes create what’s basically a massive sonar shock.

Scientists have placed sensors all around the place, and by listening in to these vibrations and applying a lot of math they can figure out where the earthquake originated, how the shockwaves bounced afterwards (shockwaves tend to partially bounce when material density changes) and how dense the materials were that the shockwaves transmitted through.