How many galaxies are there?
Focus on: grouping galaxies
What is an elliptical galaxy?
What is an irregular galaxy?
Focus on: peculiar galaxies
Do galaxies usually exist in groups?
Which is the most distant galaxy?
Focus on: the galaxy we live in
What is the nearest galaxy to ours?
How fast does a galaxy move?
Focus on: colossal collisions
Who discovered that galaxies exist?
How do astronomers use light to study galaxies?
How do astronomers count galaxies?
When did galaxies start to form?
Are new stars forming in galaxies?
Are galaxies forming now?
Focus on: gravity: a galactic glue
What are some remaining mysteries about galaxies?
