If you look at the sky above you, during the night time, you’ll notice that it is full of tiny shining objects. Some of these objects are bright while others are dim. Most of them, seem to be twinkling. The reality is not all of the objects in the sky can be seen with the naked eye. It is our solar system which is full of these objects. So let’s study the solar system in detail.
The sun, the moon, and all the objects, shining in the night sky are known as the Celestial Bodies. This includes every natural object that is located outside the Earth’s atmosphere, such as the Moon, the Sun, an asteroid, planet, or star. The Kuiper belt contains many celestial bodies. Even an asteroid in space is a celestial body.
Features of a Celestial Body
Some of the celestial bodies are very big and hot. They are composed of gas and have their own light and heat. These emit heat in large amounts. Such celestial bodies are known as stars. The sun is also a star.
Further, when you look at the night sky, you’ll see different patterns formed by the different groups of stars. These are called constellations. Ursa Major is one such constellation. In archaic times, people used stars to determine directions during the night. The North Star known as the Pole Star indicates the north direction.
A pole star is a visible star. It is approximately aligned with the Earth’s axis of rotation. This means, that the apparent position of Pole Star is close to one of the celestial poles, and it lies approximately directly overhead when viewed from the Earth’s North Pole or South Pole.
The Pole Star always remains in the same position in the Sky. You can locate it with the help of the Saptarishi. On the other hand, there are some celestial bodies that do not have their own heat and light. They are lit by the light of the stars. Such bodies are called planets.
The Solar System
The sun, eight planets, satellites, stars and some other celestial bodies known as asteroids and meteoroids form the solar system.
Stars are the celestial bodies having their own heat and light, which they emit in large amounts. Example: The Sun is a Star.
The sun is the centre of solar system. It is huge and is made up of extremely hot gases. The sun is the primary source of light and heat for the entire solar system.
The word planet is acquired from the Greek word, ‘Planetai’ that means wanderers. Our solar system has eight planets. These are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. All of these eight planets of our solar system move around the sun in fixed paths. These paths are elongated. They are called orbits.
Until August 2006, Pluto was also a planet. But now it is called only a celestial body (dwarf planet).
The Earth is our home and the third nearest planet to the Sun. The shape of the earth is called Geoid since it is slightly flattened at the poles. Certain conditions which are necessary to support life are found only on earth. This is also the reason, why life is existing only on Earth at the moment.
If one looks from the outer space, the earth appears blue. This is because, a 2/3rds surface of the earth, is covered by water. Therefore, Earth is also known as the blue planet.
Our planet Earth only has one natural satellite which is the moon. The moon appears to be extremely big to us. This is because it is nearer to our planet in comparison to the other celestial bodies. The moon moves around the earth in about 27 days and 8 hours. On the moon, the atmospheric conditions are not favourable to support life.
The moon always moves in a synchronous rotation with Earth. This means that the same side is always facing the Earth. Every once a month, you’ll see a full moon night. It is known as Poornima. A fortnight later, you’ll not be able to see any moon at all. It is a new moon night also known as new moon night or ‘Amavasya’.
There are several tiny bodies which also move around the sun. These bodies are known as the asteroids. Asteroids can be seen between the orbit of Mars and Jupiter.
There are several tiny pieces of rocks that orbit around the sun. These are known as meteoroids. Our galaxy is a huge system of billions of stars, and clouds of dust and gases. There are several millions of such galaxies that make the universe.
A Solved Question for You
Q: Which planet is known as ‘Earth’s Twin?
Ans: Venus is known as Earth’s twin because it’s shape and size are similar to that of Earth.