Professor Dave Explains
Star Systems and Types of Galaxies
We've learned a lot about stars! We know how they form, and we know that most of them exist in galaxies. But how are they arranged within galaxies? And are there different types of galaxies or are they all the same? There is a lot to...
Crash Course
Crash Course Astronomy #38: Galaxies, Part 1
The Milky Way is our neighborhood in the universe. It's a galaxy and there are many others out there. Galaxies contain gas, dust, and billions of stars or more. They come in four main shapes: elliptical, spiral, peculiar, and irregular....