In this chapter we will see the earth as a planet in the solar system. Besides, we will also see the size of the earth, the moon, other stars and the planets in the solar system. It is a good chapter, fully informative, for the class 6 students. We are sure you will enjoy the information given here. Let’s prepare this lesson with questions and answers.
- What are called celestial bodies?
The sun, the moon and all those stars, planets, satellites, asteroids, meteoroids and the rest of the objects with or without their fixed orbits in the sky are called celestial bodies.
- What are stars?
Some celestial bodies are very big and hot. They are made up of gases. They have their own heat and light, which they emit in large amounts. These celestial bodies are called stars. The sun is a star.
- Why do stars look smaller than the Sun?
Stars look smaller than the Sun because they are very far from us.
- What are constellations?
Constellations are groups of stars that make a pattern in the sky. Ursa Major or Big Bear is one such constellation. One of the most easily recognisable constellation is the small bear or Saptarishi.
- What is the specialty of the North Star?
The North Star or Pole Star remains to the North of the Earth. Locating the North Star, people used to determine the direction in the ancient times.
- How did people determine the direction with the help of North Star?
In ancient times, people used to determine directions during the night with the help of the North Star. Because the North Star indicates the north direction, people located the North Star and determined the North direction and the other directions.
- What is full moon? How many times do we see the full moon in a month?
It is full moon when the Moon is fully visible. We can see the full moon only once in about a month’s time so the night in which the Moon is fully visible is called the full moon night or Poornima.
- What is new moon?
It is a New moon night or Amavasya. On this day, you can watch the night sky best, provided it is a clear night.
- Why can’t we see the moon and all those bright tiny objects during day time?
We cannot see the moon and all the bright stars during day because the very bright light of the sun does not allow us to see all these bright celestial bodies.
- How does the Earth and the Moon shine although they do not shine by themselves?
The earth is a planet so it doesn’t shine by itself. When we see the earth from another planet or from the Moon, the Earth is found shining. This is because the Earth gets all its heat and light from the sun.
- What do you know about the Moon?
Moon is Earth’s only natural satellite. Moon has a diameter of only one-fourth that of the earth. The moon moves around the earth in about 27 days. It takes exactly the same time to complete one spin. As a result, only one side of the moon is visible to us on the earth. The moon does not have conditions favourable for life. It has neither water nor air.
- What are the two movements of the Moon?
The moon moves around the earth in about 27 days. While the Moon moves around the Earth, it also makes a spinning movement at the same speed, taking the same time.
- Why does the Moon appear almost as big as the Sun?
The Moon appears so big because it is nearer to the earth than other celestial bodies, especially the Sun. It is only about 3,84,400 km away from the Earth while the Sun is 150 million km away from the Earth.
- Why do we see shapes on the Moon?
The Moon has mountains, plains and depressions on its surface. These cast shadows on the moon’s surface so the Moon appears like a planet with shapes.
- Who was the first human to land on the Moon?
Neil Armstrong was the first man to step on the surface of the moon on 29 July 1969.
Planets in the Solar System
- What are planets?
Celestial bodies that do not have their own heat and light are called planets. The Earth and the Mars are planets.
- How did the word ‘planet’ originate?
The word planet originated from Greek word “Planetai” which means ‘wanderers’.
- Greek is a language used by the people of Greece, Europe.
- Planets move around the sun and similar stars so they are wanderers.
- Define solar system.
The sun, nine planets, satellites and some other celestial bodies known as asteroids and meteoroids form the solar system. We often call it a solar family, with the sun as its Head.
- What is the Sun’s position in the Solar System?
The sun is in the centre of the solar system. It is huge and made up of extremely hot gases. It provides the pulling force that binds the solar system. The sun is the ultimate source of heat and light for the solar system.
- Why don’t we feel the extreme heat of the Sun?
The Sun’s tremendous heat is not felt so much by us because despite being our nearest star, it is far away from us. The sun is about 150 million km away from the earth.
- Name the eight planets in the Solar System.
There are eight planets in our solar system. In the order of their distance from the sun, they are – Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
- What is the origin of the word Solar System?
‘Sol’ in Roman mythology is the ‘Sungod’. ‘Solar’ means ‘related to the sun’. The family of the sun is, therefore, called the solar system.
- What are orbits?
The planets of the solar system move around the sun in fixed and elongated paths. These paths are called orbits.
- What do you know about Mercury?
Mercury is nearest to the Sun. It takes only about 88 days to complete one round along its orbit.
- Why is Venus said to be Earth’s twin?
Venus is considered as ‘Earth’s-twin’ because its size and shape are very much similar to that of the earth.
- What is planet 2003 UB313?
Planet 2003 UB313 has been discovered recently in our solar system. It is bigger than Pluto and farthest from the Sun.
- What do you know about the Earth?
The earth is the third planet nearest to the Sun. In size, it is the fifth largest planet in the Solar System. It is slightly flattened at the poles.
- Why is the earth’s shape described as Geoid?
Because the Earth is slightly flattened at the poles, its shape is described as a Geoid. Geoid means an earth-like shape.
- What makes the earth a unique planet in the Solar System?
Only the earth has several conditions favourable to support life. The earth is neither too hot nor too cold. It has water and air, which are very essential for the survival of life. The air has life-supporting gases like oxygen.
- Why is the Earth called a blue planet?
From the outer space, the earth appears blue because two-thirds of the surface of the earth is covered by water.
- What are asteroids?
Asteroids are tiny celestial bodies which also move around the sun. They are too small in size in comparison with stars, planets and satellites. Scientists are of the view that asteroids are parts of a planet which exploded many years back. Asteroids are found between the orbits of Mars and Jupiter.
- Which is the largest asteroid?
The largest asteroid is the Ceres.
- What are meteoroids?
Meteoroids are small pieces of rocks which move around the sun. Sometimes these meteoroids come near the earth and tend to drop upon it. During this process due to friction with the air they get heated up and burn causing a flash of light.
- How do meteoroids fall on the Earth?
Most meteoroids do not reach the earth’s atmosphere because they burn out before entering the earth’s atmosphere. Very rarely, some meteoroids without being completely burnt, fall on the earth. It leaves a hollow in the place.
- What is the Milky Way Galaxy?
The Milky Way Galaxy is a cluster of millions of stars. It looks like a whitish broad band, like a white glowing path across the sky. Our solar system is a part of this galaxy.
- Why did ancient Indians name the Milky Way galaxy as Akash Ganga?
The ancient Indian astronomers imagined the Milky Way galaxy to be a river of light flowing in the sky. Because it was a celestial (Akash) river (Ganga), the ancient Indians named it Akash Ganga.
- What is the Universe?
It is very difficult to imagine the Universe. The Universe is the total of millions of galaxies like the Milky Way.
- What are satellites?
Satellites are celestial bodies that move around the planets in the same way as the planets move around the sun. The Moon is the only natural planet of the Earth.
- What are human-made satellites?
Human-made Satellites are electronic devices designed by scientists to gather information about the universe or for communication. Such satellites are launched off to the space by rockets and placed in the orbit around the earth.
- Name some of the satellites launched by India.
Some of the Indian satellites in space are INSAT, IRS, EDUSAT, etc.
- Who are astronomers?
Those who study the celestial bodies and their movements are called astronomers.
- Name an India astronomer of ancient India.
Aryabhatta was a famous astronomer of ancient India.
- What are the rings found around Jupiter, Uranus and Saturn?
The rings found around Jupiter, Saturn and Uranus are belts of debris.