Earth Science

Introduction

The classification of science is not limited to the umbrella branches of Physics, Chemistry, and Biology. Instead, even under these branches, we have hundreds of subbranches based on various factors like areas of application, concepts concerned, concepts studied, etc.

Classification is important since it makes advanced studies easier. For example, up till high school, you study the umbrella branches of Physics, Chemistry, and Biology. But the concepts taught at this level are simple and limited. When you go to the graduate or postgraduate level, your syllabus is advanced, and therefore, you cannot study two branches at once. Instead, you choose one branch and study major portions of it for three to four years. But beyond the postgraduate level, the concepts are even more advanced and their applications are even more focused. Thus, it becomes essential and useful to classify the topics under the branches of science.

In this tutorial, we will discuss a branch of natural science known as Earth Science. Note that natural science is the study of natural phenomena.

What is Earth Science?

Earth science is also known as geoscience. It is the study of all phenomena, theories, effects, etc. which are related to the planet Earth. The most interesting part about Earth science is that it is not just limited to Physics. Instead, geoscientists study the physical, chemical, as well as biological phenomena related to Earth.

Another topic that is of immense importance in Earth science is the relations between the various “spheres” of the Earth (the biosphere, the hydrosphere, the atmosphere, and the geosphere). While most scientists focus on planet Earth, some also use their knowledge of Earth science to study its neighboring planets.

Other topics of study under Earth science include environmental impact and factors. You must have heard about some action plans or schemes put into place to protect flood plains or forests in certain areas. The approach involved in such action plans is developed by Earth scientists.

Basic Area of Earth Science

The areas studied under Earth science can be broadly classified into various major topics. Here is a quick summary.

Geology

The geological study is the study of the rocky part of the Earth. The study of minerals, fossils, rocks, etc. falls under the purview of geology.

Physical Geography

Physical geography studies climates, seasons, atmosphere, oceans, landforms, etc. It is further classified into climatology, meteorology, ecology, etc.

Atmospheric Sciences

As the name implies, atmospheric science studies the atmosphere of the Earth. The atmosphere extends from the surface of the Earth to about 1000 km to the exosphere.

Soil Science

Scientists studying soil science focus on Earth’s soil and its formation and composition. Soil scientists also study the upper layer of Earth’s crust where the soil is formed.

Earth Interior

The interior portion of the Earth can be thought of as concentric layers. These layers are centered on the center of our planet and differ from each other in terms of composition and temperature. Roughly, we can classify them as follows

Core

The core is the innermost part of the Earth and can be thought of as a solid sphere of about a 1216km radius. Since it lies embedded deep within the Earth, it is subject to massive pressures and thus, the hottest part of our planet. Scientists believe the temperature of the core is similar to that of the surface of the sun, i.e., about 5778 K.

Mantle

A major part of our Earth’s volume (approximately 84%) is taken up by the mantle. It is mostly solid and has a thickness of approximately 2900km. The heat and pressure inside the mantle increase as we go deeper and while the surface is only about 1273K, the deepest part of the mantle can get as hot as 3973 K. This is still much colder than the core.

Crust

Finally, the crust is the outermost part of the Earth and it forms the surface on which we live and breathe. It is the thinnest part of the Earth and only makes up 1% of the planet’s total volume. The crust is made up of a large number of elements of which, oxides and oxygen are the most abundant.

Earth Atmosphere

The atmosphere of the earth is also known as air, and it refers to a giant envelope of gases that surrounds the planet from its surface to about a thousand kilometers to the top. It is made up of various layers. Here is a quick summary

Troposphere

This layer extends up to an average height of 12 km. This is the part of the atmosphere where weather phenomena take place. Further, almost 80% of the mass of the atmosphere is concentrated in this region.

Stratosphere

The stratosphere extends to an average height of 55 km and is the part of the atmosphere containing the Ozone layer. There are no weather phenomena in this layer and airplanes fly in this region.

Mesosphere

The mesosphere is the third-lowest layer of the atmosphere and goes up to a height of 80-85 km. The top of the mesosphere is the coldest region on Earth and has average temperatures of around $\mathrm{-85^{\circ}C}$.

Thermosphere

The second last layer of the atmosphere is the thermosphere, which extends to a height of almost a thousand kilometers. However, its height varies a lot whenever there is solar activity. This layer is incredibly rare, i.e., the density of the thermosphere is extremely low. Even though the temperature here is almost $\mathrm{1500^{\circ}C}$, you wouldn’t feel anything over there since the molecules of air are too far apart to conduct any heat.

Exosphere

The outermost layer is known as the exosphere, and it goes into space up to a height of 10,000 km above the Earth’s surface. While there are molecules of gases in this layer, they are so far apart that the exosphere is not consistent, and its molecules consistently escape into space.

Importance of Earth Science

One of the biggest factors that make the study of Earth sciences essential is our environment. Currently, mankind is consumed with a passion for environmental destruction and industries are of no help. The study of how to reduce a negative impact on the environment can significantly aid in making sure the Earth does not become uninhabitable.

Another factor that makes Earth science important is that it encompasses the study of minerals and resources, which are essential for society’s survival. Further, studying volcanoes and volcanic eruptions comes under Earth science and can aid in the timely evacuation of areas that might be in danger. The study of natural disasters also helps us in disaster management and prevention.

In a nutshell, Earth science is inseparable from the survival of our species and there are a plethora of factors that make its studies not only important but also necessary.

Conclusion

Earth science is a branch of natural science that deals with the physical, chemical, and biological phenomena related to the planet Earth. Earth science is further divided into a large number of fields, chief among which are geology, geography, atmospheric sciences, soil sciences, etc.

The interior of Earth is composed of three main layers: the crust, the mantle, and the core. The crust is the innermost and the hottest part, while the mantle forms about 84% of the Earth’s total volume and lies above the core. Above it is the crust, which is the thinnest layer. We live on the crust. Earth’s atmosphere is an envelope of gases that surrounds the planet, and it is also known as air. It regulates heat on Earth, and all weather-related phenomena take place in the lowest layer of the atmosphere, known as the troposphere.

FAQs

Q1. Is Earth science a branch of physics?

Ans. The division of branches of science is difficult to summarize in a few words. However, Earth science is not a branch of Physics. Rather, it is a branch of natural science, which includes physical as well as biological sciences. Thus, Earth science encompasses portions of physical, chemical, and biological sciences.

Q2. Are the oceans a part of the Earth’s crust?

Ans. No. Oceans exist on top of the crust itself. The crust is the solid part of the land beneath us. Thus, inside the oceans, the ocean bed is the crust, not the ocean itself.

Q3. How significant is Earth science in terms of the environment?

Ans. Environmental studies aren’t entirely about Earth sciences. There are other portions to it as well. However, Earth science forms a major component of environmental studies. For instance, the sustainable development goals set by the United Nations are seventeen in number, nine of which include Earth sciences components.

Q4. If Earth science includes the study of fossil fuels, what happens once we run out of these fuels?

Ans. Changes and updates in theories occur every day. The future of renewable energy like solar, wind and geothermal energies also fall under the purview of Earth sciences.

Q5. Which part of the atmosphere do planes fly in?

Ans. Most commercial airlines fly in the stratosphere. The Mesosphere above it is only accessible to rocket-powered aircraft.