The milky way is our galaxy with over 400 billion stars, two trillion planets, interstellar dust and gases. Our solar system is a part of the milky way galaxy. It spans about 1,00,000 light years in diameter which means light takes 1,00,000 years for light to travel from one end of the milky way to the other. All the stars, dust and planets including our earth in the milky way are held together with gravity. Let’s explore some more interesting facts about the milky way galaxy, its formation, evolution, structure and location of earth in it.

What is Milky Way Galaxy
Formation and Evolution of Milky Way Galaxy
Structure of Milky Way Galaxy
Center of the Milky Way Galaxy
Our Earth in the Milky Way Galaxy

What is Milky Way Galaxy

The milky way galaxy is a barred spiral galaxy surrounded by a spherical cloud of stars. The center of the galaxy is known as halo. These stars, including our sun, revolve around the core or halo of the galaxy in a galactic disk. It is difficult to see the center of the galaxy and many scientists believe that there is a super massive black hole at the center of it called Sagittarius A. The core is surrounded by stars revolving around it in a galactic disk made of cold hydrogen, nebulous and cosmic dust. The objects outside the galactic disk also revolve around the halo but not in the organized way as the stars in the galactic disk do.

Formation and Evolution of Milky Way Galaxy

Our galaxy formed 13.6 billion years ago, which is very close to when the universe formed.

The whole event of the formation of our milky way galaxy can be divided into two parts: the halo or core and the disk.The formation of these two parts is separated from each other by around eight billion years. The core or halo of the galaxy formed as a result of the inward implosion of primordial gas clouds to form oldest stars and violent collision between smaller galaxies over billions of years.

The younger part of the galaxy is the galactic disk with its spiral arm. This region was formed when the surrounding gas clouds revolved around the core due to gravity. They whirled more quickly as it shrank due to gravity and the spherical clouds flattened into a pancake-like disc, settling into the plane of rotation.

Structure of Milky Way Galaxy

At the nucleus of the milky way galaxy is believed to be a super massive black hole called Sagittarius A. It is covered with over 10 millions stars tightly packed together. The galactic bulge is a central region around the nucleus of the galaxy that acts as a gravitational anchor for the rotating disk. This is a flat layer consisting of stars, cosmic gas, interstellar dust and spiral arms. This is part of the milky wave where most of the stars are located, including our sun.

Center of the Milky Way Galaxy

It is difficult to see the center of the galaxy due to millions of closely packed stars surrounding it along with interstellar dust and cold gases. The scientists believe that there is a massive black hole in the nucleus of the milky way galaxy. It is named as Sagittarius A.

Our Earth in the Milky Way Galaxy

Our earth is located about 26,000 light-years away from the centre of the milky way. We are present in the orion arm which is one of the spiral arms of the milky way galaxy. It is located between the other two primary spiral arms of the milky way galaxy called sagittarius arm and perseus arm. From earth the milky way appears as a faint and hazy luminous band in the night sky.

Andromeda is another galaxy located around 2.5 billion light years away from the milky way and hurtling towards it. It also has a central supermassive black hole that is expected to eventually spiral with the milky way to form a new galaxy. This event will take over millions of years to happen and before that the sun will already be nearing its end.