how do scientists know the Earth’s core is liquid if no one has ever seen it or extracted a sample?

Question

how do scientists know the Earth’s core is liquid if no one has ever seen it or extracted a sample?

In: Earth Science

Answer 1

Earthquakes generate different kinds of seismic waves that behave differently when passing through different materials. Notable, one of the types of waves (S waves) don’t pass through liquids. This creates a kind of “shadow” that tells us that part of the core is liquid. But the behavior of the other kind of waves (P waves) also tells us that there is something solid inside that liquid.

Here is a picture for reference:

[https://akm-img-a-in.tosshub.com/indiatoday/images/story/201602/seismic-waves-650_042715041742.jpg](https://akm-img-a-in.tosshub.com/indiatoday/images/story/201602/seismic-waves-650_042715041742.jpg)