Hello and this is
Maanvinder and I’m back with another episode. Today I I will tell you about a
fascinating group of galaxies, our galaxy is part of. But before I move
forward, I want you to imagine no of galaxies in our universe. 1, 2 or 5
million or 1 billion or 200 billion. If your answer is more than 200 billion,
then you are correct. There are between 200-300 billion galaxies in our
observable universe. And these galaxies are not just scattered through the
universe, in fact they are part of a large group of galaxies due to their
mutual gravity, just like the star clusters I told you about in the previous
episode but in this case its on a large scale, we are talking millions of light
years and they are galaxies and not individual stars in a galaxy. Such kind of
group of galaxy is “Local Group”. Local Group is dumb-ball shaped like group of
galaxies. Our own Milky Way galaxy is part of this group. When I said
dumb-ball, I meant it looks like that with Andromeda, our neighbor galaxy at
one lobe and Milky Way at the other. The Local Group was first recognized by
the American astronomer Edwin Hubble.
The Local Group has around 80 galaxies and most of them
are either dwarf galaxies or satellite galaxies. The three largest members of
the Local Group are: Andromeda or M31; the biggest, Milky Way; the second-
biggest and Trapezium Galaxy; third biggest. The two biggest galaxies in the
group are spiral galaxies and accounts for most of the mass in the group. Each
of these two galaxies has their own system of satellite galaxies which revolves
around them. Another interesting thing about these two galaxies is that they
are on a collision course with each other and in about 5 billion years they
will completely merge into each other forming a new galaxy and who knows maybe
will be called as ‘milkomeda’. Local Group has roughly a diameter of 10 million
light years and is part of a very large cluster of galaxy groups called Virgo
Supercluster which is located 70 million light years from the centre of Local
Group. There’s still debate over the centre of Local Group but it is believed
to lie between Andromeda and Milky Way.
The current computer models has predicted the future of
Local Group to be a large single elliptical galaxy. Tens of billions of years
into the future all galaxies in the system will merge into each other. After
Andromeda and Milky Way will merge into each other along with their satellite
galaxies, then the third biggest member of this system, the Trapezium galaxy
will merge into the newly formed “milkomeda”. And this merger will continue
until all the galaxies merge into each other. As you know the universe is
expanding so all the galaxies are moving away from ours except those who are
part of the Local Group, so in the future there will be just one galaxy as all
the other galaxies will pass the horizon and we will never be able to see them,
what will be left is that large single elliptical galaxy. So its time to know
about some galaxies other than the big three I told you about.
So at number one we have Magellanic Clouds. These are two
satellite galaxies of the Milky Way. Large Magellanic and Small Magellanic
Cloud are their names. What is more interesting about these two that there is a
bridge called “Magellanic Bridge” between them which is a stream of hydrogen
connecting these two galaxies where stars from SMC are being pulled towards
LMC. SMC is located some 197,000 light years while LMC is located approximately
163,000 light-years from the Earth and
is on the collision course with the Milky way. It will merge in about 2.5
billion years.
So this was from me for this episode. I hope you love it
and let me know about it in the comments, polls or review section of the
platform you are listening this podcast on.
