Module 4: Radiation and the Electromagnetic Spectrum

The basic building blocks of all objects in the universe are atoms. By studying the atomic structure of stars, you can understand why they differ in color, temperature, and brightness. How, though, can an astronomer study the atomic structure of stars that exist so far away from earth? By observing the light that stars emit and the patterns in stellar spectra, astronomers study how atoms interact with light to produce spectral lines. These spectral lines are important to astronomers because every element has its own specific spectral signature. The spectrum contains information about the chemical composition of the star and the star’s motion relative to Earth. In this module, you will explore atoms, which are the basic building blocks of everything. Then, you will examine the electromagnetic spectrum, and how astronomers use their knowledge of this spectrum to determine the temperature of a star. Finally, you will learn about the Doppler effect and its presence in everyday life and across the universe.

Getting Started

How much do you already know about stars, the energy they emit, and how they are studied from here on Earth? In this non-graded activity, read each statement and decide whether it is True or False. Then, click SUBMIT to check your answer. Click the interactivity thumbnail, and then click NEXT to get started.

Key Vocabulary

To view the definitions for these key vocabulary terms, visit the course glossary.