1. Seismic Waves: These are vibrations that travel through the Earth, generated by earthquakes or man-made explosions. Geologists study the way these waves travel through different layers of the Earth, how they are reflected or refracted, and their speeds. This data allows them to map the different layers of the Earth and their composition. For example, the discovery of the Earth's core was made through analyzing seismic wave patterns.
2. Rock Samples: Although directly accessing the Earth's mantle and core is impossible, geologists can study rocks from deep within the Earth that have been brought to the surface through volcanic eruptions or tectonic activity. These rocks provide insights into the composition and conditions of the deeper layers. For example, studying the composition of mantle rocks helps us understand what the mantle is made of and how it behaves.
These two types of evidence complement each other, providing a comprehensive picture of the Earth's interior structure and composition.
