PPT on Science Day Description of observed Observable universe.pdf

Presentation on The Description of the observable Universe . The Presentation on the Indian National Science Day 2026.

1. GOVT. COLLEGE DHALIARA
NATIONAL SCIENCE DAY, CELEBRATED ANNUALLY ON
FEBRUARY 28, HONORS THE DISCOVERY OF THE
RAMAN EFFECT BY C.V. RAMAN. THE 2025 THEME
EMPHASIZESYOUTH EMPOWERMENT IN SCIENCE AND
INNOVATION, ALIGNING WITH INDIA’S VISION FOR
DEVELOPMENT.

2. Introduction
We live on a planet the earth whose radius is
6400km and mean density approximately
5gm/cm^3. The earth to sun distance is just
adequate for earth temperature to be
compatible with the maintenance of animated
life.

3. SUN
MASS = 2*10^33 g i.e3.3*10^5 times more then the earth .
AVERAGE RADIUS = 7*10^10 cm i.e. 100 times more than the earth.
EXTERNAL TEMPERATURE = ~5700 k (Sun is yellow star)
MEAN DENSITY= 1.5 g/cm^3

4. ❖The solar photos which are seen from the EARTH are
emitted by the external zones of the SUN.
❖Inside the SUN, there is a source of energy able to
provide a luminosity of 4*10^33 erg/s and this since
4.6*10^9 year.
❖The radiation is mainly transferred from the central
region to the external layers by a succession of photon
emission and absorption. Therefore, we have no direct
information on what occurs in the central region of the
SUN. the only way to obtain direct information on the
central regions of the SUN, is to measure the neutrinos
which may be produced there.
❖The SUN is also an emitter of radio waves.
❖The Sun is a slow rotator (it rotates with a period of 28
days)
❖All the mass of the solar system is in the Sun , the angular
momentum of this system is in the planets.
❖The Sun is surrounded by a hot corona (very rarefied gas
as hot as 10^6k)
❖The Sun is an ordinary star among the about 10^11 stars
which constitute our galaxy.
]

5. DIFFERENT CLASSES OF PLANETS
Close to sun
 Mercury :- Closest to sun , does not have atmosphere.
Venus :- It is hottest planet of the solar system .It does not have moon also
known as evening and morning star.
Earth :- It is known as blue planet( 71% of earth is covered with water and
remaining 29% is land).
Mars:- It is known as red planet because of its reddish appearance which is
caused by iron oxide, its diameter is half of the size of earth.
 These four planets are closest to sun and are called telluric
planet or inner planets, they are solid bodies of rather small radius but large
density surrounded by gaseous atmosphere.

7. Far away from sun
Jupiter :- It is largest planet in our solar system ,made up mostly of
hydrogen and helium .It has 95 confirmed known moons.
Saturn :- Second largest planet after Jupiter , least dense planet so
that it would float in water . It has 146 confirmed moons.
Uranus :- It is ice giant with a blue green color. It has 28 moons.
Neptune :- Farthest planet from the sun . It is blue in color. It has 16
moons with short day and long year.
 These plantes are called outer plantes or
major planets . They are much larger but less dense . They are in
liquid form .

8. STARS
The stars are massive bodies, produce light and heat.
Nuclear fusion – H atoms fuse to form He atoms, releasing large
amounts of energy.
Stars vary in size, temperature and brightness.
Hotter stars are blue or white, while cooler stars are red or orange.
Stars form patterns in the night sky known as CONSTELLATIONS.
Stars are far away from Earth, with distances measured in light-years.
Stars are essential to the formation of elements and the overall
structure of the universe.

10. GALAXY
Galaxy is a large system of stars,gas,dust and dark matter bound together
by Gravity. Galaxies are fundamental building blocks of the Universe
Structure:- contain billions or trillions of stars and other celestial
bodies, elliptical shape.
Size:- range from 1000 to 100000 light-years in diameter.
Movement:- Galaxies are not stationary but move through
space.They can collide and merge, which may lead to the
formation of new stars.
Dark Matter:- Galaxies contain large amounts of dark matter
that doesn’t light but exerts gravitational effects. Dark matter
consist most of Galaxy’s mass.
Redshift:- The light from galaxies moving away from us is
redshifted.
Galaxy Clusters:- Galaxies are found in groups called
CLUSTERS. These clusters can contain hundreds or thousands of
Galaxies bound by gravity.
Life cycle of a Galaxy:- Over billions of years, galaxies evolve.
Observation:- Galaxies are observed using Telescope.

11. MILKY WAY GALAXY
Our home galaxy is the Milky Way. It contains over 100 billions stars
and has a supermassive black hole at its center. It is a vast, complex
galaxy and studying it helps us learn more about the universe’s
structure, history and future.
Size and Shape:- Diameter of about 100000 light-
years and contains 100 billion stars.
Location :- Our solar system is located in one of the
spiral arms, called the Orion Arms.
Supermassive Black Hole:- At the center of the Milky
Way is a supermassive black hole, with a mass
about 4 million times that of the Sun.
Rotation:- The milky Way rotates around its center. It
takes the Solar System about 230 million years to
complete one full orbit around the galactic cente,
a period known as a Galactic Year.
Visibility:- The Milky Way is visible as a bright band
across the night sky. It represents the disk of the
galaxy as seen from earth.

12. THANK YOU