Galaxy Basics

Gathering Online Data

Go to http://www.galaxyzoo.org/classify and start looking at the galaxies. As you go through each galaxy, draw it's basic shape. Follow the prompts, but don't limiti your observations to the questions being asked. Take about 5 minutes. When you get done, and have seen at least 15 galaxies, and have 10 or more observations, try to define a galaxy in your own words. Conside what you have seen,

Now, go back to GalaxyZoo and go through the tutorial. As you do this, write down another 10 observations.
Partner with some one else and compare your observations. One good way to do this is a t-chart, or Venn diagram. This can tell us what a galaxy is and what a galaxy isn't. Share at least two questions you still have below your diagram for when your class is discussing your findings.

Classifying Galaxies

Go to http://btc.montana.edu/ceres/html/Galaxy/galunknsheet.html and sort the galaxies into at least 4 categories. Explain what each category has for characteristics. The parts of a galaxy might be helpful.


Compare your classification system to those of others. How are they similar? Different?
Why do people pick one system for classifying over another? Can you think of classifying systems in some of these categories:

* Biology
* Sports
* Medicine
* English
* Other…

Share examples of classification in the world. What makes one system ‘right?’

Misconceptions In Action
Edwin Hubble's misconceptions were reflected in his ideas about the evolution of galaxies and the diagram you see at the top of this lesson. Read the article (but don't do the Exercise) before posting to the forum on galaxy selections and explain what you think is happening.


Our Own Misconceptions

Take the time to create your own pictures of the Milky Way from a top view and a side view using the data found in The Galaxy Song by Eric Idle. Your teacher may play the accompanying song:





Just remember that you're standing on a planet that's evolving
And revolving at nine hundred miles an hour,
That's orbiting at nineteen miles a second, so it's reckoned,
A sun that is the source of all our power.
The sun and you and me and all the stars that we can see
Are moving at a million miles a day
In an outer spiral arm, at forty thousand miles an hour,
Of the galaxy we call the 'Milky Way'.
Our galaxy itself contains a hundred billion stars.
It's a hundred thousand light years side to side.
It bulges in the middle, sixteen thousand light years thick,
But out by us, it's just three thousand light years wide.
We're thirty thousand light years from galactic central point.
We go 'round every two hundred million years,
And our galaxy is only one of millions of billions
In this amazing and expanding universe.

The universe itself keeps on expanding and expanding
In all of the directions it can whizz
As fast as it can go, at the speed of light, you know,
Twelve million miles a minute, and that's the fastest speed there is.
So remember, when you're feeling very small and insecure,
How amazingly unlikely is your birth,
And pray that there's intelligent life somewhere up in space,
'Cause there's bugger all down here on Earth.


Compare your picture to known data of the Milky Way, and to an analysis of the song. Why are galaxies difficult to visualize?