# The Redshift, Hubble’s Law and the Expansion of the Universe.

Paper for 8 points.

The Redshift, Hubble’s Law and the Expansion of the Universe.

A- Briefly discuss the concept of “redshift” and its application to determine the speed of resection of stars and galaxies.

As an example determine the speed of resection of the galaxy whose emission spectrum is shown below.

B- Discuss the work done by Edwin Hubble. ( observations, and the law that he discovered)

C- The following table gives the distance and the recession speed of some galaxies.

 Speed of Recession Km/s Distance( Mpc) 2500 35 5000 72 8000 118 10000 142 13000 180 17000 254 22000 312 30000 426 35000 485 39000 550 45000 652
1-Graph the data given in the table using two perpendicular axis. Horizontal axis:  distance  in Mpc Vertical axis:  Speed of recession in Km/s.

2- Calculate the slope of the graph plotted in C1. [This slope is known as the Hubble constant H0]

D- The graph given below shows the relationship between the speed of recession and distance of  supernova Type Ia found in other galaxies.

Use the graph to calculate the value of Hubble’s constant. Compare this value with the value you obtained in C2. (COMMENT YOUR RESULTS)

D- Hubble’s constant is used to estimate the age of the universe. Use the value of H0 that you found C2 to estimate the age of the universe.

F. Why is it important to know the true value of the Hubble’s constant?

Rubric.

-Format and Length of Work.

MLS or APS .  Eight  pages (minimum) double space .(Times New Roman font 11.)

Excellent or 8 points : The different points outlined above are clearly stated. The calculated values are accurate.

Acceptable  (4 points)

The different points outlined above are clearly stated but some basic information is missing. The calculated values are not accurate.

Poor: (2 points).

The different points outlined above are confused and basic information is missing. The calculated values are not correct.

Note . You can use the text book as one of the references.

Due Date: November 15. Top