Hubble's Law: An Introductory Astronomy Lab


E.P.Hubble at Palomar

Edwin Hubble Discovers the Universe is Expanding

Credit: Mt. Wilson Archive, Carnegie Institution of Washington Explanation: No person in history has had greater impact in determining the extent of our universe than Edwin Hubble. From proving that other galaxies existed to proving that galaxies move apart from one another, Hubble's work defined our place in the cosmos. Hubble lived from 1889 to 1953 and is shown above posing with the 48-inch telescope on Palomar Mountain and his famous pipe. In memory of his great work, the Orbiting Space Telescope was named after him. Today a great controversy rages on the rate of the universe's expansion, parameterized by a quantity known as Hubble's constant.

Picture and caption from Astronomy Picture of the Day, February 17, 1996. Corner animation adapted from an illustration at STScI public information site.
The measurement techniques for this lab have had to be changed to a server-independent method. There WILL be places within these instructions where the directions do not correspond to the new method. We are working on updating all parts of the lab, but completion is in the future. In the meantime, if users would refer to the shortened version that uses pre-selected galaxies, they would find updated instructions as well as spread sheets and other useful tools. ENJOY!

Table of Contents

All of these instruction sheets and the student answer sheets are available for downloading:
Hubble Law instruction sheets and student answer sheets.

Steps 1 and 2

Steps 3 and 4

Measuring the Velocities and the Distances
Data Table Sheet (PDF)

Steps 5 and 6

Graphing, Data Analysis, and Questions
Table of Results and Questions Sheet (PDF)

Link to the Clickable Images and Spectra [real data]

The lab was originally designed by Luis Mendoza and Bruce Margon with lots of technical support from Eric Deutsch, Toby Smith, and Brooke Skelton, as well as present and past members of the University of Washington Astronomy Department.

The galaxy spectra were obtained by Robert C. Kennicutt Jr. of the University of Arizona, and are published in The Astrophysical Journal Supplement Series, volume 79, pages 255-284, 1992, and are also available on the WWW. The digital images of the galaxies have been extracted from the CD-ROM version of the Palomar Observatory Sky Survey, which was produced under NASA contract by the Space Telescope Science Institute, operated by AURA, Inc. We gratefully acknowledge the various copyrights for that work.

This lab represents modifications (especially to the measuring methods) and additions made by Ana M. Larson to the original Hubble Law Lab. The real credit goes to the people involved in the original package.

The Hubble Law Lab has gone international: Legea Hubble: un laborator de Astronomie introductivă (thanks to Alexander Ovsov)

© 2011 University of Washington
U.W. Astronomy Department Homepage