This PowerPoint is an educational material to study The Depths of the Inner Galaxy. This would be helpful for young people.

1. The Depths of
Inner Galaxy
Krishnaraj Ramakrishnan

2. The Galaxy
• What is a Galaxy? A galaxy is according to
astronomy theory is all existing matter and space
is considered as a whole; the cosmos. The
universe is believed to be at least 10 billion light-
years in diameter and contains a vast number of
galaxies; it has been expanding since its creation
in the Big Bang event about 13 billion years ago.
• It is said that at the moment, there are 100 billion
galaxies in this universe though it might be so
that telescopes will improve in coming years,
Scientists state 200 billion galaxies are in this
universe.
This Photo by Unknown Author is licensed under CC BY

3. How was the
Universe made?
• Well, the universe began with an explosion of
space itself - the Big Banging from extremely
high density and temperature, space expanded,
the universe cooled, and the simplest elements
formed. Gravity gradually drew matter together to
form the first stars and the first galaxies.
• What did the Universe contain as chemical
compounds? The chemical compounds of the
Universe are dominated by the hydrogen and
helium produced in the Big Bang. The remaining
90 or so chemical elements are produced in stars
and constitute only a few percent of the overall
mass.
This Photo by Unknown Author is licensed under CC BY-SA-NC

4. Who invented the
theory of the Big Bang?
• Georges Lemaître, was part of the Cosmic
Horizons Curriculum Collection. According
to the Big Bang theory, the expansion of
the observable universe began with the
explosion of a single particle at a definite
point in time. Georges Lemaître, (1894-
1966), Belgian cosmologist, Catholic
priest, and father of the Big Bang theory.
• Why did Georges Lemaître invent the Big
Bang theory? Well, The universe began,
scientists believe, with every speck of its
energy jammed into a very tiny point. This
extremely dense point exploded with
unimaginable force, creating matter and
propelling it outward to make the billions of
galaxies of our vast universe.
Astrophysicists dubbed this titanic
explosion the Big Bang.
This Photo by Unknown Author is licensed under CC BY-NC-ND

5. Have they launched detailed
missions for the Big Bang
theory?
• Yes, NASA has launched two missions
to study the cosmic background
radiation, taking "baby pictures" of the
Universe only 400,000 years after it was
born. The first of these was the Cosmic
Background Explorer (COBE).
This Photo by Unknown Author is licensed under CC BY-SA-NC

6. What did scientists propose
would have happened in
the Big-Bang?
• According to the Big Bang theory, the
expansion of the observable universe began
with the explosion of a single particle at a
definite point in time. Georges Lemaître,
(1894-1966), Belgian cosmologist, Catholic
priest, and father of the Big Bang theory.
This Photo by Unknown Author is licensed under CC BY

7. Missions to discover the
depths of the Universe
• There have been missions by NASA to
discover the universe. Voyager 1 is a space
probe launched by NASA on September 5,
1977, as part of the Voyager program to study
the outer Solar System and interstellar space
beyond the Sun's heliosphere. Voyager 2 is a
space probe launched by NASA on August 20,
1977, to study the outer planets and
interstellar space beyond the Sun's
heliosphere.
This Photo by Unknown Author is licensed under CC BY

8. Thank You for
Watching.
• Don’t forget to like and subscribe to this
Channel for more videos. Please press the
bell icon. Thank You!
This Photo by Unknown Author is licensed under CC BY