A Universe of Galaxies

Edwin Hubble’s observations of the Andromeda “nebula” in 1924, using the then new 100 inch telescope at Mount Wilson Observatory, lead to the understanding that the Milky Way was not the only galaxy, but one of a countless large groups of stars in our Universe. Within this new field of astronomy, Hubble devised a classification system for galaxies based on their observed shape and structure. In this laboratory exercise, you will use Stellarium to observe a number of galaxies and attempt to classify them using Hubble’s system.

Background Question – Describe the major Hubble galaxy classifications and how they are organized on Hubble’s “turning fork”.

Object: Explain the purpose of this laboratory assignment in your own words. What do you think you will accomplish or learn from this exercise?

Hypothesis: Write a simple hypothesis connected to observed properties of galaxies that you will be able to test using the Stellarium software (for example, most galaxies are spiral in shape like our Milky Way).

Procedure

1) Open the Stellarium software. Open the Sky and Viewing options window (F4). Under the “Sky” tab, uncheck the Atmosphere.

2) Select the Landscape tab and uncheck “Show ground”.

3) Open the Search window (F3) and enter Andromeda Galaxy. The view should shift to center on the Andromeda Galaxy. Scroll your mouse wheel forward to zoom in until you can see the Andromeda Galaxy in detail.

4) Based on the Andromeda Galaxy’s shape and appearance, record on the lab data table which major type of galaxy you think it is (Spiral, Elliptical, Irregular). Make a note if you see any particular interesting features (color, if spiral is there a bar, if a galaxy is interacting with another galaxy)

5) Repeat steps 3 and 4 for each galaxy listed on the data table. You make need to zoom in or out to see the selected in detail.

Q1: From the list of galaxies given, did you find more of classification group then the other?

Q2: Did you observe any spiral galaxies with a bar structure?

Q3: Where all the elliptical galaxies all the same exact shape?

Q3: Did you notice a difference in general color between elliptical and spiral galaxies?

Q4: Which classification group showed evidence of ongoing star formation (visible new O and B blue stars)?

6) Continue using Stellarium if you need further information to test your individual hypothesis. If you need further direction, please ask your instructor.

Conclusion: In 1-2 paragraphs, explain if your observations and data support or conflict with your hypothesis and if you have met your assignment objective. Was there any portion of the assignment that was particularly interesting or difficult?

Galaxy

Classification Type

Interesting Features

Andromeda

M33

LMC

SMC

M51

M58

M60

M63

M81

M82

M86

M87

M88

M90

M91

M94

M99

M100

M102

M106

M109