In the universe, stars are not distributed evenly. Instead these stars clump together to form large clusters called galaxies. Thus, a galaxy is a large group of billions of stars. Galaxies also contain large clouds of hydrogen gas and dust particles. From these gas clouds new stars are born. The number of galaxies present in the universe is about 100 billion (1011). Also, the average number of stars present in a galaxy is about 100 billion (1011). So, the total number of stars present in the universe is about 1022.
Galaxies in the Universe
Milky way galaxy and andromeda galaxy are the two important galaxies present in the universe. Out of these two galaxies we will discuss only about milky way galaxy because our solar system is present in milky way galaxy.
Milky Way Galaxy
Milky way is our galaxy. It consists of about 200 billion stars and is spiral in shape. Its Indian name is akash ganga. Looking up from the earth, it appears as a river of light running from one corner of sky to the other. That is why, it is called milky way or akash ganga. Our galaxy keeps on rotating slowly around its centre.
Types of Galaxies in the universe
The galaxies are classified into three types based on their shapes.
- Spiral Galaxies
It is believed that about 30% galaxies in the universe are spiral in shape.
- Elliptical Galaxies
Most of the galaxies in the universe are elliptical in shape.
- Irregular Galaxies
Many galaxies in the universe do not have a definite shape, so these galaxies are called irregular galaxies.
Test Your Understanding and Answer These Questions:
- What is milkyway?
- How many galaxies are there in the universe?
- How many stars are present in a galaxy?
- What are types of galaxies?