Name: ________________________ DUE 11/24 ID number: ________________________

Homework 13. Testing Hubble's Law

How would you test Hubble's law? Answer this question in stages. As always, be sure to use your own words in your answers. The goal of this exercise is understanding, and using your own words proves that you understand.

First, how would you test any proposed law of nature? (HINT: it may help to review Homework 7, where you tested Kepler's 3rd law.)

Second, what is Hubble's law? Give a brief definition. (HINT: Hubble's law is a simple mathematical relationship between any galaxy's ____________ and its ____________; what goes in the blanks, and what is the relationship between them?)

Third, how do you go about measuring the two properties of a galaxy which are related by Hubble's law? (HINT: at least two different kinds of observations are required. What are they?)

Fourth, how do you use the results of your measurements to actually test Hubble's law?

Continue on the back.

Joshua E. Barnes (
Last modified: November 17, 1999