The milky way
The milky way is a huge body of billions of stars. The stars remain bound to the galaxies, for this the gravitational force is responsible among the four fundamental forces: gravitational force, electromagnetic force, strong force and strong force.
There are approximately 100 billion galaxies in the universe and each galaxy contains an average of 100 billion stars. That means the total number of stars in the universe is 10²².
In addition to stars, every galaxy also contains gas and dust. 98% of the galaxy is made up of stars and 2% is made up of gas and dust.
Due to the vastness of the galaxy, it is also called the peninsula universe.
Classification of the milky way
Galaxies are generally divided into three classes on the basis of their shape.
- Spiral
- Elliptical
- Irregular
Of the galaxies known so far, 80% are spiral, 17% elliptical and 3% irregularly shaped.
Our galaxy is the Milky Way or Milky Way and its nearest galaxy is Andromeda, 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 a galaxy called the Milky Way. Its diameter is approximately 10⁵ light years and it is rotating at a churning speed.
The milky belt galaxy slowly rotates around its center and the stars rotate slowly around its center. The Sun (along with the Solar System) also rotates around its center. It takes approximately 250 crore years to complete one revolution. People on Earth are able to see the front view of the Milky Way Galaxy because Earth itself is part of this galaxy.
The stars in our galaxy are contained in a flat disk-like structure which extends up to 10⁵ light years in space. The ring of stars is quite thick at the center, indicating the relatively high concentration of stars at the center of the galaxy.
Our Sun is far away from the center of the Milky Way Galaxy. If the sky is clear, then on a dark night the Milky Way appears as a broad band of light white stars stretching from north to south, made up of millions of twinkling stars. When seen from the earth in the dark night, it appears like a flowing river in the sky, it is called milkyway.