Viru's Babble: Milky Way Galaxy

Milky Way Galaxy

Till now, we read about two beautiful galaxies, Andromeda and Whirlpool; now let’s know some interesting things about our home galaxy - Milky Way (MW).

One funny aspect is that the thing got named long before knowing what it was. As you may already know, during a dark night, mostly away from urban lights, a white band is seen across the sky. Earlier, till end of 19th century, even scientists used to think all that we see is universe and every things (stars/clusters) is contained within our structure, later to be proven otherwise.

That milky band is actually part of the disk of our galaxy, it is mostly obscured by dust. We can NOT see our own galaxy completely for obvious reasons, though we know that it is a “Barred Spiral Galaxy”.

Apart from being our home, there is nothing special about MW, in terms of size, it has about ‘just’ 100 to 400 billion stars (compared to about 1 Trillion in Andromeda) and a diameter of only of about 1,00,000 (1 Lakh) light years (ly) compared to about 2.2 ly of Andromeda. I have given a comparison picture to show where MW actually stands and how tiny we are in the whole scheme of things.

MW will be merging with Andromeda in about 4 billion years to form a much larger elliptical galaxy.

While most of our galaxy is invisible to us, the Fermi Gamma-ray Space Telescope mission for detected a beautiful, awe inspiring phenomenon. It discovered two extremely large Gamma ray emission bulges/bubbles ‘above’ and ‘below’ the galactic center. These are formed due the super-massive black hole at the MW center that is devouring nearby stars at a high rate; while mass is eaten by the black hole, some radiation escapes to form these structures.