Chapter 5, Problem 1QQ

Choose the best answer to each of the following. Explain your reasoning.

What is the name of the rigid outer layer of a planet?

1. crust
2. mantle
3. lithosphere

To determine

The outermost rigid layer of planet

Answer to Problem 1QQ

The rigid outermost layer of a planet is the Lithosphere.

Explanation of Solution

Introduction:

Based on physical and mechanical properties and composition, a planet is divided into five layers. Lithosphere, Asthenosphere, Mesosphere, outer and inner core.

The outermost rigid layer of planetis Lithosphere which is made up of rigid part of mantle and crust. By mechanical properties, lithosphere is composed of brittle rock portion of the surface of thickness around $\text{100}\text{km}$ .This layer of surface of planet is subdivided into 7 major tectonic plates. Some major events, like earthquakes and volcanoes occur in this outermost layer. In terms of temperature, this lithosphere is the coolest layer among all the layers.

Conclusion:

Lithosphere is the outermost rigid layer of a planet.