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The Hidden Lives of Galaxies - Answer Key for Activities

Answer Key for Activities

Activity #1 - How Big is the Universe
1. What is the total size of the Milky Way Galaxy? 100,000 light years
2. The visible universe will be a sphere approximately 12 km in radius.

Activity #2 — Identifying Galaxies
1.Titles will vary, but may be, e.g. "The Galaxy Types", or "Five Types of Galaxies"

A. Spiral — galaxy with tightly wound spiral arms
B. Elliptical — slightly elliptical to nearly circular
C. Barred Spiral — spiral with a bright bar of gas through the center
D. Peculiar — fits none of the descriptions
E. Irregular — small, patchy, irregularly shaped galaxy

2. Identify the types of the ten galaxies labeled on the Deep Survey Image.

A. IrregularF. Barred spiral
B. SpiralG. Elliptical
C. SpiralH. Spiral
D. EllipticalI. Irregular (or Peculiar)
E. Barred spiralJ. Elliptical

Assessment

Inferences that can be made from observing the Hubble Deep Survey Image should include that the objects are galaxies and not stars. These galaxies are of different sizes, shapes, brightnesses, distances, and color.

Activity #3 — Classifying Galaxies Using Hubble’s Fork Diagram
Galaxy Classification Chart

Galaxy

Scheme

Classification

Andromeda

Spiral

Sb

M84, NGC4374

Elliptical

E1

NGC 2997

Spiral

Sb

NGC5383

Barred Spiral

SBb

Large Magellanic

Irregular

Ir

NGC4622

Spiral

Sb

M83

Spiral

Sc

Centaurus A

Peculiar

P

M59, NGC4621

Elliptical

E5

NGC1365

Barred Spiral

SBc

Assessment

1. Examples of how to classify objects in everyday life may include organizing a CD collection, sorting clothes, organizing magazines.

2. An example of how classifying helps organize one’s life may be that an organized CD collection makes it easier to locate music by artist name or music type.




 

A service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA/GSFC

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