The Science Behind Geologic Hazards and the Environment

On July 19 of 2013, thousands of people gathered to celebrate as our planet ‘took a selfie’ for the third time in its history. The camera traveled on NASA’s Cassini spacecraft, which photographed the Earth at a distance of approximately 898 million miles (1.45 billion kilometers) from Earth. The image showed our home as a dot, not distinguishable from other bright spots in the dark cosmic background. It was a sobering reminder that our Grand planet is but a speck of dust in the immense universe. As Carl Sagan’s best said it: “the Earth is a very small stage in the vast cosmic arena” (Sagan, 1994).

The Day the Earth Smiled.jpg
Figure 1.1 The Day the Earth Smiled. The arrow shows planet Earth and the moon as seen from Saturn.


Yet, our “Pale Blue Dot” is everything to us. It is all that we have. We depend on our planet and we will continue to do so, at least in the near future. This may be the reason why many cultures refer to our planet as Mother Earth maintaining relationships of reciprocity and gratitude. We have a responsibility to learn about our home. If we are to survive and thrive on this planet for millions of years to come, or at least until we can migrate to another planet, then we must take care of our home, our planetary body. To use Carl Sagan’s words again:

“To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the Pale Blue Dot, the only home we’ve ever known.”

Our lives are so intertwined with our Earth that even modest changes to the Earth’s systems have shaped the course of civilization. Understanding Earth’s systems and how they interact with us is vital for our survival and for a resilient future. The Geosciences study our planet’s dynamics and materials. An understanding of the basic pillars of the Geosciences will allow you to understand the Earth’s influence on you and of your influence on Earth, and this will be the focus of our first chapter. We can only preserve our world if we know something about it.

Welcome to this journey!

Learning Objectives

By the end of this chapter, you will be able to:

  • Explain how Earth scientists apply the scientific method to study geologic hazards and the environment.
  • List the Earth spheres of the Earth system and define the main relationships among them.
  • Recognize the difference between science denial and science skepticism.


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Dynamic Planet: Exploring Geological Disasters and Environmental Change Copyright © 2021 by Charlene Estrada, Carolina Michele Londono, Merry Wilson is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.

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