short astonomy paper
brodwa
hubbles_law_disl_2.docxThe 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.
Emission spectrum of Galaxy NGC 5548.
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)
The Hubble diagram for type Ia supernovae. From the compilation of well observed type Ia supernovae by Jha (29). The scatter about the line corresponds to statistical distance errors of <10% per object. The small red region in the lower left marks the span of Hubble's original Hubble diagram from 1929. Taken from http://www.pnas.org/content/101/1/8.full
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.)
Grading.
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.
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
H
0]
Emission spectrum of Galaxy NGC 5548.
