Chapter 26, Problem 8RQ

What is the evidence that Earth’s outer core is liquid?

To determine

The evidence that Earth’s outer core is liquid.

Answer to Problem 8RQ

S-waves cannot travel through liquid and thus they cannot travel through the outer core, which makes it evident that Earth’s outer core is liquid.

Explanation of Solution

PWhen P-waves reach the core-mantle boundary, they get reflected and refracted. While traveling from the outer core to the inner core, P-waves gain speed suddenly when it reaches the inner core. The P-waves properties are similar to sound waves. Sound waves travel faster in the solid materials whereas slower in the liquid material. Therefore, the outer core is evidently to be liquid.

S-waves cannot travel through liquids and thus, they cast a pronounced shadow. And they are only reflected at the core-mantle boundary. Therefore, the reflection of these seismic S-waves implies that outer core is liquid.

Conclusion:

Therefore, S-waves cannot travel through liquid and thus they cannot travel through the outer core, which makes it evident that Earth’s outer core is liquid.