Laurie A. Lewis

SLM-521 Green Group 2

Dropin #5

For Science Classes Grs. 8-12

 

 

How Are Celestial Distances Measured?                                                            

 

 

 

     The distances between the objects in the Universe are so great that it is difficult to get a feel for how large these distances are.  Today we are going to look at how the distances between celestial bodies are measured.  In order to do so, we are first going to visit a page of NASA’s StarChild web site that explains the various units of measure scientists use to describe these distances.

 

              Please click on the picture

                                                                                                                    to begin your visit.

 

During your visit, please read the text, define the following terms, and answer the questions on the paper provided: 

 

Please define:

 

1.      light-year                                                                       

2.      parsec

3.      astronomical unit

 

Questions: 

 

     1.  Why do astronomers use the light-year as a unit of measure?

     2.  Why do you think astronomers use the parsec as a unit of measure?

     3.  Why do you think astronomers use the astronomical unit as a unit of measure?

 

                      

     Now we are going to look at the distances between the planets in our own Solar System and the Sun using the BBC’s Science & Nature site online.  Click on each planet’s name to visit the page devoted to that planet.      Once you reach the web page for each planet, please navigate to the section entitled Facts and Figures that is located to the left, below the picture of each planet, in order to find the information you seek.  Read all the information, and then record the planet’s distance from the Sun.  Once you have written down these distances in kilometers, please convert the distances into astronomical units using the definition that you recorded earlier.  You may use the graphing calculators provided.   Then, please make a bar graph showing the distance of each planet from the Sun in astronomical units (AU’s).  Please use increments of 1 AU for your Y-axis, and estimate the height of the bars for those planets having values of less than 1 AU.

                                                               

 

 

 

       Mercury     Venus   Earth

 

                                                                   Mars    Jupiter        Saturn

 

                                                                   Uranus    Neptune    Pluto