The Earth is the third planet from the Sun and the only astronomical body known to harbor life. Although there are large amounts of water present throughout the Solar System, Earth has the distinction of having liquid surface water, namely the ocean. With seventy-one percent of its surface covered by water, the ocean dwarfs the ice caps, polar regions, lakes, and rivers. So, how does water get to Earth? Well, as we’ll see, water is abundant on Earth.
The structure of the Earth is essentially made of layers and regions. The interior is the core. The outer layers are the mantle, the crust, and the hydrosphere. These layers make up the oceans, which are found in low parts of the Earth’s crust. The atmosphere is divided into spherical zones including the troposphere (where the weather occurs), the stratosphere, and the magnetosphere, an enormous region of space that reflects the Earth’s magnetic field.
The study of Earth’s atmosphere and oceans is considered “Earth system science.” Researchers at NASA study Earth’s various components to learn about how the planet changes. Some changes are natural, while others are caused by human activity. Understanding the history of Earth’s processes helps scientists predict changes that may affect Earth in the future. For example, in the study of the hydrologic cycle, scientists study the impact of water on the atmosphere, climate change, and ocean acidification.
Scientists refer to different parts of the Earth system as “spheres.” These components include the atmosphere, hydrosphere, biosphere, cryosphere, and geosphere. However, these spheres can’t be considered in isolation – each part of Earth interacts with the others. A deconstructed view of the Earth system is more harmful than helpful. So, in the end, the Earth is a complete system and our efforts to save it should be more focused on integrating the parts.
Scientists have measured the size and shape of the Earth using geodesy. Satellites can measure Earth’s size to centimeter accuracy. Pictures taken from space show that the Earth is round, like the moon. But, it’s not a perfect sphere, and the South Pole is flat. And, as the planet is rotating, it is changing shape slowly. The melting glaciers may also be contributing to the uneven shape of Earth. Therefore, scientists need to consider the effects of climate change when studying the shape of Earth.
While it is difficult to measure the heat produced in the Earth’s interior, scientists know that the temperature is increasing. Temperatures on the surface of the earth are 1,800 degrees Fahrenheit, while the temperature in its interior rises by 3 degrees Fahrenheit per mile or one degree Celsius every km. Geologists think that the inner core is hotter than the surface of the sun. Nonetheless, these temperatures are not enough to support life on Earth.
Scientists study Earth using a full set of modern instruments. This detailed knowledge enables scientists to understand the inner structure and composition of Earth. Scientists can determine the age of objects by the amount of radioactive elements trapped in minerals. The separation of lighter elements from heavier ones releases additional energy for geologic processes. It also alters the composition of the crust. So, how do scientists study Earth? What are the benefits of studying the inner structure of the Earth?