Our Universe for Class 3

Our Universe

a) Our Universe is a vast and incredible expanse filled with many things like dust, gas, galaxies, planets, stars, rocks, clouds, and living creatures like us.
b) Stars and galaxies make up a small part of the entire universe. Galaxies are enormous systems of stars, gas, and dust held together by gravity.
c) Our solar system, which includes eight planets, their moons, asteroids, comets, and meteoroids, orbits around the sun.
d) We are part of the Milky Way Galaxy, which contains millions of planetary systems like ours, and the universe itself has millions of galaxies.
e) The planets in our solar system, their moons, stars, and other celestial bodies are like our neighbours in this vast universe.

Planet Earth

a) Earth is our home in the vast universe. It is the third planet from the sun and receives enough sunlight for life to exist.
b) Earth is surrounded by a layer of air called the atmosphere, which contains gases like nitrogen, oxygen, and carbon dioxide that are important for life.
c) Three-fourths of Earth's surface is covered in water, which is why it is sometimes called the "blue planet."
d) Earth has both land and water on its surface. Its shape is called an oblate spheroid, meaning it is a bit bulged at the equator and flatter at the poles.

Our Solar System

a) In the middle of our solar system, we have the sun.
b) The solar system is made up of the sun, planets, their moons, dwarf planets, comets, meteors, and some rocks and gases.
c) If we look at the shape of the solar system, it's like a stretched-out oval. We call this shape an "ellipse." It's kind of like a squashed circle.

Planets

a) Each planet has its own special path, kind of like a road or a track. We call these paths "orbits." The planets follow these orbits and go around the sun in a fixed path.
b) We can group them into two types: the inner planets and the outer planets.

Planets in Our Solar System

Each planet of the solar system is special and unique in its own way, with different sizes, colours, and moons.

1. Mercury

a) It's the smallest planet and the one closest to the Sun.
b) It takes 88 days for Mercury to go around the Sun.
c) Mercury doesn't have any moons.

2. Venus

a) Venus is the second planet from the Sun.
b) It's known as the hottest planet and often called Earth's "sister planet" because they are similar in size.
c) People sometimes call it the morning or evening star because you can see it in the sky at dawn and dusk
d) Venus also doesn't have any moons.

3. Earth

a) Earth is the third planet from the Sun.
b) It's also called the blue planet because it has lots of water. We have air to breathe, which is very important for living things.
c) Earth has one moon.

4. Mars

a) Mars is the fourth planet from the Sun.
b) It's often called the red planet because it has a rusty colour. Mars has really tall mountains and deep canyons.
c) Mars has two moons.

5. Jupiter

a) Jupiter is the fifth planet from the Sun, and it's the biggest planet in our solar system.
b) It's so big that it has 95 moons.

6. Saturn

a) Saturn is the sixth planet from the Sun.
b) It's the second-largest planet.
c) Saturn is famous for its beautiful rings made of ice and dust.
d) Saturn has 146 moons.

7. Uranus

a) Uranus is the seventh planet from the Sun.
b) It's the third largest planet.
c) Uranus is a bit different because it spins on its side.
d) Uranus has 27 moons.

8. Neptune

a) Neptune is the eighth planet, and it's the farthest one from the Sun.
b) It's really cold and windy on Neptune.
c) Neptune looks blue because of something called methane.
d) Neptune has 14 moons.

Frequently Asked Questions

1. What causes day and night on Earth?

Earth spins on its axis once every 24 hours. When your part of Earth faces the Sun, it's day. When it faces away, it's night.

2. How are planets different from stars?

Planets are smaller, do not produce their own light, and orbit stars. Stars are huge, hot balls of gas that make their own light.

3. What is the Milky Way?

The Milky Way is the galaxy in which we reside. It is home to billions of stars, including the Sun.

4. What are the layers of Earth?

Earth has three main layers: the crust (where we live), the mantle (hot, semi-solid rock), and the core (made of very hot metal).

5. What is Earth made of?

Earth is made up of layers, including the crust, mantle, outer core, and inner core. The surface has land, oceans, and air (the atmosphere).

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