2. What is a galaxy?
A galaxy is a massive, gravitationally bound system consisting
of stars, stellar remnants, an interstellar medium of gas and dust, and dark
matter
3. How many are there?
Estimated that there are 170 billion different galaxies
Space in between galaxies is known as “intergalactic space”
4. Type and Classification
There are 3 main types of galaxies, though subtypes are not uncommon
1.
Spiral galaxies
2.
Elliptical galaxies
3.
Irregular galaxies
7. Elliptical galaxies
Shaped like an elongated sphere
Sometimes look almost football shaped
Classified based on elongation from a perfect circle
• Scale from E0 to E7