The universe is made up of all matter and space, including astronomical objects like stars, planets, satellites, comets, and asteroids. Originally, all matter was in one place and exploded in an event called the Big Bang, spreading matter outwards to form the astronomical objects seen today. Galaxies contain billions of stars and objects, including the Milky Way galaxy which contains our solar system orbiting the Sun along with eight planets. The document goes on to define stars, planets, satellites, asteroids, comets, and meteors. It also describes geocentric and heliocentric models of the solar system and provides details about the Earth, its rotation, revolution, and the cause of seasons and the moon's phases.

1. UNIT 1

2.  The UNIVERSE is all the matter and space
that exists.
 It is made up of astronomical objects:
- stars
- planets
- satellites
- comets
- asteroids
- meteors

3. Where did the Universe come from?
All the matter in the Universe was once all in
one place.Then, there was an enormous
explosion (The Big Bang). Pieces of matter
expanded in different directions and they are
the different astronomical objects in the
Universe.

4. Galaxys are enormous clouds which contain
billions of stars and other astronomical objects.
Our galaxy is called the Milky Way.

5. The Solar System is part of the MilkyWay
galaxy.
The Sun is the star at the centre of the Solar
System.There are eight planets.
-Mercury -Jupiter
-Venus - Saturn
-The Earth - Uranus
- Mars - Neptune

6.  STARS:They are enormous balls made up of
hydrogen and helium.They produce their own
energy.
 PLANETS:They are smaller than stars and they
don`t produce their own energy.
 SATELLITES:They orbit planets. EX.The Moon.
 ASTEROIDS:They are rocks that orbit the Sun.
 COMETS:They are burning bodies of rock and dust
which orbit the Sun.
 METEORS:They are fragments of comets.

7. THE SUN
- The sun is the star at the centre of our Solar
System.
- It is a small star, but we see it bigger than
other stars because it`s the closest to the
Earth.

8. GEOCENTRISM AND HELIOCENTRISM
Geocentrism: many years ago people believed
that the Sun and the planets orbited the
Earth.
Heliocentrism:The idea that the Sun was the
centre of the Universe and the Earth and
other planets orbited the Sun (Copernicus
and Galileo).

9. THE EARTH
The Earth has various internal layers and an
atmosphere which has different layers too:

10. The Earth moves in two different ways.
- It rotates on its axis: ROTATION
- It orbits the Sun: REVOLUTION

11. - This movement produces day and night in
different parts of the world.
- One rotation of the Earth takes 24 hours.

12.  This movement produces the different
seasons .
 The Earth takes 365 days to complete one
revolution.

13.  The Moon orbits the Sun. It takes 28 days to
complete one revolution.
 During this days we see the moon in different
shapes.This shapes are called Moon`s lunar
phases.

15. The Earth goes between
the Sun and the Moon and
blocks the Sun`s light to
the Moon.
The Moon blocks the Sun`s
light to the Earth.