Lesson: Redshift Physics • 9th Grade
In this lesson, we will learn how to calculate the radial velocity of a star or galaxy using the amount by which absorption lines in the spectrum of light from it are shifted.
Sample Question Videos
The diagram shows the spectral lines in the light from two galaxies, as well as the same spectral lines in the light from a laboratory source.
How is Galaxy A moving relative to Earth?
How is Galaxy B moving relative to Earth?
Which galaxy is moving faster relative to Earth?
The diagram shows the absorption lines in a spectrum from a distant star compared to those in a spectrum from a laboratory sample. How is the star moving relative to Earth?
An astronomer looks at the absorption lines in the spectrum of light coming from a distant galaxy. He identifies the absorption lines of hydrogen, which makes up most of the galaxy. He then compares these lines to the same absorption lines from a laboratory sample. His results are shown in the diagram.
How is the galaxy moving in relation to Earth?