SME
Grade 12 Science · Problem type
Kinds of galaxies
Use this for “What do all galaxies have in common?” and for sorting galaxies by shape.
Sort
What type of galaxy is it?
Tap a card, then tap its group.
Assumptions
•
Every galaxy holds a great many stars, from thousands to trillions, bound by gravity.
•
Galaxies are sorted by shape: spiral, elliptical or irregular.
Topic check
See what you know: 5 questions on this topic
New questions each time. Pass to mark it complete.
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Related lessons
The Milky Way, galaxies, the Big Bang and the expanding universe
Main lesson
A galaxy’s redshift and distance
Use this for “A galaxy’s light is shifted to longer wavelengths, z = 0.03. How fast is it moving away, and how far is it?”
Space stretching: every galaxy moves apart
Use this for “Space doubles in size. How far does a galaxy 100 million light-years away move?”
The history of the universe
Use this for “Put the events since the Big Bang in order. What is the microwave background?”