About This Chapter
1. Galaxy: Definition & Explanation
Galaxies are collections of stars, dust, and gas rotating around super massive black holes. This lesson will cover the structures and types of galaxies, including spiral, elliptical, and irregular galaxies.
2. Proto-Galaxies: Definition & Explanation
A proto-galaxy is a cloud of dust and gas, primarily hydrogen and helium, that is forming into a galaxy from the force of gravity. This lesson will define and go over the processes of a proto-galaxy.
3. The Big Dipper Constellation: Facts & North Star
The Big Dipper is one of the most famous constellations in the sky. . . or is it? This lesson will explore these seven easy-to-locate stars and their relation to Polaris, the North Star.
4. Planetary Nebula: Definition & Facts
Planetary nebulas are perhaps one of the most spectacular sights in the night sky. Learn the definition of a planetary nebula and take a look at some of the most famous ones in the universe in this lesson.
5. Quasar: Definition & Overview
In this lesson we will explain what quasars are, why they were so puzzling when discovered, and how they can look quite different when observed from different angles. A short quiz will follow.
6. Irregular Galaxy: Definition, Facts & Names
Galaxies come in many forms and shapes, and irregular galaxies are those that have no form or structure to them. Making up roughly 25% of all galaxies in the universe, they are important in understanding the evolution of galaxies. After this lesson, there will be a quiz to test your knowledge.
7. Nebula: Definition & Theory
A nebula is a large cloud of gas and dust particles. Nebulae are known as nurseries for stars, while at the same time most are created by the death of stars. This lesson will define and explain nebulae.
8. Spiral Galaxy: Definition & Facts
Spiral galaxies are one of the classifications of galaxies designated by the Hubble Classification System. Our own galaxy, the Milky Way, is considered a Spiral Galaxy. This lesson will define Spiral Galaxies and provide facts about them.
9. The Milky Way Galaxy: Stars, Center & Pictures
Our galaxy, the Milky Way, is home to our sun, along with around 250 billion other stars. This lesson will cover the features of our galaxy and provide a quiz at the end to test your knowledge.
10. Cosmic Microwave Background Radiation: Definition & Overview
This lesson defines cosmic microwave background radiation, including the history behind its discovery and what this tells us about the universe as a whole. A short quiz will follow.
11. Elliptical Galaxy: Definition, Examples & Facts
Elliptical galaxies are one of the galaxy classifications in the Hubble Classification System. These galaxies are older than most other galaxies and only make up a small part of all galaxies. This lesson will cover the classification methods and facts about elliptical galaxies.
12. Orion Constellation: Stars & Belt
In this lesson, we will focus on the constellation Orion. Soon you can impress your friends with your keen ability to locate this stellar hunter while you amaze them with a touch of both mythology and astronomy.
Earning College Credit
Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.
To learn more, visit our Earning Credit Page
Transferring credit to the school of your choice
Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.
Other chapters within the General Studies Earth & Space Science: Help & Review course