The discovery and understanding of Earth’s core did not come from physically reaching the bottom of the ocean. Instead, scientists have gained knowledge about the Earth’s core through a combination of seismology, laboratory experiments, and theoretical models.

Seismology, the study of earthquakes and seismic waves, played a crucial role in understanding the Earth’s interior. When an earthquake occurs, it generates seismic waves that travel through the Earth. By measuring and analyzing these waves, scientists can infer the properties of the Earth’s interior, including the existence of the core.

Seismic waves travel at different speeds depending on the density and composition of the materials they pass through. By observing the behavior of seismic waves, scientists noticed that certain types of waves, known as primary waves (P-waves), undergo a distinct change in velocity and path when they reach the Earth’s core. This change, known as the P-wave shadow zone, led scientists to conclude that the Earth must have a core.

In addition to seismic data, laboratory experiments have been conducted to simulate the extreme pressures and temperatures found in the Earth’s interior. By subjecting materials to high pressures and temperatures and studying their behavior, scientists gained insights into the properties of materials under such conditions and how they relate to the Earth’s core.

Furthermore, theoretical models and computer simulations have been developed to explain the observations from seismic data and laboratory experiments. These models incorporate knowledge of material properties, heat flow, and the behavior of Earth’s interior over time. By combining all these pieces of information, scientists have developed a comprehensive understanding of the Earth’s core.

It’s important to note that while we haven’t physically reached the Earth’s core, our knowledge about it is based on extensive scientific research and a combination of different lines of evidence.