Science Olympiad Dynamic Planet Practice Test

What is the name of the layer surrounding the solid sphere at the center of the Earth?

1. Asthenosphere

2. Outer core

3. Lithosphere

4. Crust

The correct answer is: Outer core

The layer surrounding the solid sphere at the center of the Earth is known as the outer core. This layer is composed mainly of liquid iron and nickel and lies above the inner core, which is the solid center of the Earth. The outer core plays a critical role in generating the Earth's magnetic field through the movement of these molten metals. The other layers mentioned, such as the asthenosphere, lithosphere, and crust, are situated above the outer core. The asthenosphere is part of the upper mantle and is semi-fluid, allowing tectonic plates to move over it. The lithosphere includes both the crust and the uppermost mantle and is rigid. The crust itself is the outermost layer of the Earth, consisting of solid rock, and is significantly less dense than the layers beneath it. Understanding the Earth's structure and the composition of each layer is fundamental to studying geology and planetary science.