The Milky Way
There are about 100 billion galaxies in the universe and an average of 100 billion stars in each galaxy. That is, the total number of stars in the universe is 10²². In addition to the stars in each galaxy, there are also gases and dust. 98% of Milky Way is made up of stars and 2% is made up of gas and dust. Due to the vastness of the Milky way, it is also called the peninsula universe.
Classification of Galaxy
Galaxies are often divided into three classes based on their shape.
The galaxies known so far are 80% spiral, 17% elliptical, and 3% irregular. Our galaxy is the Milky Way and its nearest Milky way Andromeda is a spiral-shaped galaxy. Spiral galaxies are much larger than other galaxies.
Our own galaxy The Milky way
Our solar system is a member of the Galaxy or Milky Way. Its diameter is about 10⁵ light years and it is revolving at a churning speed.
The Milky way is slowly moving around its center and the stars revolve slowly around its center. The Sun also revolves around its center (including the Solar System). It takes about 250 million years to complete a circuit. On Earth, people are able to see the oriental view of the Milky way, as the Earth itself is part of this galaxy.
In our galaxy, the stars are covered in a flat circular structure that extends up to 10⁵ light years inside the space. The disk of stars is quite thick at the center, indicating a relatively high concentration of stars at the center of the galaxy.
Our sun is quite far from the center of the galaxy. If the sky is clear, the Milky Way appears as a broad strip of light white stars stretching from north to south in the dark night, consisting of billions of twinkling stars.
When seen from the earth in the dark night, it appears like a flowing river of the sky, this sky is called Ganga.