Module 5

The FOSS Planetary Science Course focuses on the anchor phenomenon of Earth as an object in space. The driving question for the course is what is my cosmic address? Astronomy is the study of everything we can observe and imagine beyond Earth—the Moon, the Sun, the solar system, the Milky Way, and the vastness of the cosmos. Astronomers ask fundamental questions: When and where did the universe start? Why is it expanding? What is its destiny? Astronomers endeavor to answer these questions by determining the kinds and numbers of objects in the cosmos, their composition, their motions, and their interactions with one another. Because Earth is part of this ultimate system, the science of astronomy includes the study of our own planet.

Astronomers are the pioneers who travel back in time along paths of light reaching out to Earth from stars millions of light-years away. These celestial census takers and cartographers are creating an increasingly coherent picture of a universe abuzz with stars, many hosting families of orbiting planets.

And here we now stand on a small, rocky planet orbiting a typical star, in a typical galaxy, peering into the night sky with a sense of anticipation. There is a growing sense that we are probably not alone. Will we detect life in the universe in our lifetimes? When it does happen, those who share in the discovery will witness the opening of the next chapter in the amazing story of life.