The Milky Way is a Spiral Galaxy and is the galaxy where our Solar System is
located. No one knows exactly what the Milky
Way Galaxy looks like from the outside. It is a spiral-shaped galaxy, with arms
that resemble the shape of a spinning firework.
The most visible part of our
own Milky Way Galaxy is part of the sky that looks like a misty cloud. It is
really a band of millions of stars. The part that we can actually see is called the Milky Way. When we look at it, we are looking at the centre of our
Galaxy where most stars are. We cannot actually see the centre because
we are situated a long way from the centre of the Orion arm, an outer arm of the
Galaxy. When we look at the region where the famous Orion constellation is
situated, there seem to be fewer stars. This is because we are looking towards
the edge of the Galaxy.
If we could look at it from the side, the Milky Way Galaxy would be rather thin
disc with a dense, bulging centre surrounded by a halo. This halo is a mass of
older stars surrounding the central mass, which contains the most stars. The
thinner edges of the disc are the outer arms of the Galaxy.
In addition to the millions of stars in the Milky Way Galaxy, there are also
many nebulae, which are regions where stars are being born.
About our Galaxy
The Milky Way Galaxy is about 2000 light years thick (tall) but 100,000 light
years across. It contains an estimated 100,000 million stars. There is a bulge
in the center of it. The Milky Way also has a halo that has a radius of 50,000
light years, which is above the nucleus. The halo is made up of very old stars
called globular clusters.
Age
The Milky Way is believed to be more than 13 billion years old.
Location of our Sun
Our Sun, which is one of those stars in the Milky Way Galaxy and is about
30,000 light years from the centre. It orbits the centre of the Galaxy at a
speed of 274 kilometres per second.
*
The speed of light: Light from our Sun takes just 8 minutes.
* The Greek philosopher Democritus (450–370 BC) was the first known person to
propose that the Milky Way might consist of distant stars.
* A galaxy is made up of billions or trillions of stars bound together by their
own gravity and there are millions of galaxies in the universe. Our Solar System
is in the Milky Way Galaxy and is more on the west side of the Milky Way.
* Harlow Shapley, an American astronomer (November 2, 1885- October 20,
1972 was the first person to estimate the size of the Milky Way Galaxy, as
well as our position of the Earth in the galaxy.
