Science Question Answer (2 Marks)

1. Ursa Major can be seen during summer time in the early part of the night. It has seven prominent stars.
2. Cassiopeia is another prominent constellation in the northern sky. It is visible during winter in the early part of the night. It looks like a distorted letter W or M.

Asteroids and Comets are the two objects other than planets which are members of the Solar System.

Meteor is seen as a bright streak of light coming down the night sky. A meteor is usually a small object that occasionally enters the Earth's atmosphere.

Comets are the member of the Solar System. They revolve around the Sun in highly elliptical orbits. Comets appear periodically. Comets are visible to us in the sky like a bright ball of light with a long glowing tail. The length of the tail grows in size as it approaches the sun. The tail of a comet is always directed away from the sun.

1. Mercury is the planet nearest to the Sun. It is the smallest planet of our Solar System.
2. Neptune is the farthest planet from the Sun. It is the fourth largest planet in the Solar System.

The constellation Orion is visible during winter in the late evenings. It also has seven or eight bright stars. It is also called the Hunter. The three middle stars represent the belt of the hunter. The four bright stars appear to be arranged in the form of a quadrilateral.

Light year is the unit used to express distance between the various celestial bodies. Light year is the distance travelled by light in one year. The speed of light is 300,000 km per second. For example, the Sun is nearly 150,000,000 Km i.e. 150 million Km away from the Earth. The distance of the Sun from the Earth may be said to be about 8 light minutes

Meteor is seen as a bright streak of light coming down the night sky. A meteor is usually a small object that occasionally enters the Earth's atmosphere with very high speed. The friction due to the atmosphere heats it up and it glows and evaporates quickly. As a result, the bright streak lasts for a very short time. These are commonly known as shooting stars.

The Sun is the nearest star which is continuously emitting huge amount of heat and light. Hence, the Sun appears to be bigger and brighter than all the planets. The Sun is the source of almost all the energy on the Earth.

Ursa Major is the constellation which reminds us of a large ladle or a question mark in the night sky. It is also known as the Big Dipper, the Great Bear or the Saptarshi. There are seven prominent stars in this constellation. It appears like a big ladle or a question mark. There are three stars in the handle of the ladle and four in its bowl.

Mars is known as the red planet. It appears slightly reddish in colour due to the presence of iron oxide on its surface.

There is a large gap in between the orbits of Mars and Jupiter. This gap is occupied by a large number of small objects that revolve around the Sun. These are called asteroids. Asteroids are the celestial objects which are also called minor planets. Asteroids can only be seen through large telescopes.

Meteorites are the large meteors which can reach the Earth before they evaporate completely. Meteorites help scientists in investigating the nature of the material from which the solar system was formed.

The Sun is the nearest star which is continuously emitting huge amount of heat and light. The Sun is the source of almost all the energy on the Earth.

The next nearest star to Earth is 'Proxima Centauri'. It is 4.24 light years from the Sun. Its light will take 4.24 years to reach us.

Moon is the natural satellite of the Earth. Aryabhatta was the first Indian artificial satellite of the Earth.

Uranus and Neptune have been discovered with the help of telescope. These are the outermost planets of the solar system. They can be seen only with the help of large telescopes.

ISRO also known as Indian Space Research Organisation is the agency responsible for the development of space science programs in India.

The distance between the Earth and stars and the distance between the stars is very large. It is inconvenient to express these distances in kilometres. Therefore, these large distances are expressed in light years.
1 light year = 9.46 × 1012Km. Now, a star is 8 light years away from the Earth. It means the distance between the star and the Earth is equal to the distance travelled by light in eight years.
Therefore, the star is located 8 × 9.46 × 1012Km = 75.68 × 1012Km away from the Earth.

Comets are the member of the Solar System. They revolve around the Sun in highly elliptical orbits. The period of revolution of comets around the Sun is usually very long. Comets appear periodically. Comets are visible to us in the sky like a bright ball of light with a long glowing tail. The length of the tail grows in size as it approaches the sun. The tail of a comet is always directed away from the sun.

Ursa Major constellation is also known as the Big Dipper, the Great Bear or the Saptarshi. There are seven prominent stars in this constellation. It appears like a big ladle or a question mark.

The stars appear to move in the sky. It appears because of the motion of the Earth. Earth is spinning around its own axis and also moves around the Sun. As a result, the stars also appear to move from east to west. A star which rises in the east in the evening, sets in the west in the early morning. All the stars do not appear to move. For example, pole star does not appear to move because it is situated in the direction of earth’s axis.

Saturn is the planet having a well-developed system of rings around it. These rings are not visible with the naked eye. They can be observed with a small telescope.

Artificial satellites are used for forecasting weather, transmitting television and radio signals. They are also used for telecommunication and remote sensing.

When seen from a space-ship or Moon, the Earth appears blue-green in colour. It is due to the reflection of light from the water and landmass on its surface.

Comets are the member of the Solar System which appears in the sky like a bright ball of light with a long glowing tail. The length of the tail grows in size as it approaches the sun.

Artificial satellites are manmade and are launched from the Earth. They revolve around the Earth much closer than earth’s natural satellite, the moon. They have many practical applications. They are used for forecasting weather, transmitting television and radio signals. They are also used for telecommunication and remote sensing. INSAT, IRS, Kalpana-1, EDUSAT are artificial satellites.

Planets are the members of the Solar System. They look like stars but they do not have light of their own. They reflect the sunlight that fall on them. Whereas the stars emit light of their own. The Sun is also a star.

Sirius is the brightest star in the sky. It is located close to the Orion constellation. An imaginary line is drawn passing through the three middle stars of Orion. By looking along this line towards the east, will lead to a very bright star. This bright star is Sirius.

Earth is the only planet of the Solar System having life on it. The special environment conditions are responsible for the existence and the continuation of life on the Earth. These conditions include the right distance from the Sun, so it has the right temperature, the presence of water, suitable atmosphere and a blanket of ozone.

Mars and Jupiter have asteroids between them. These planets have a large gap between the orbits. This gap is occupied by a large number of small objects that revolve around the Sun called the asteroids.

The Sun and the celestial bodies which revolve around it form the solar system. It consists of large number of bodies such as planets, comets, asteroids and meteors. The Gravitational force keeps the members of the Solar System bound to the Sun.

Venus is the hottest planet of the solar system. It is the second planet from the Sun and has a temperature that is maintained at 462º Celsius.

Ursa Major can be seen during summer time in the early part of the night. It has seven prominent stars.

Any celestial body revolving around another celestial body is called its satellite. The Earth is the satellite of the Sun because it revolves around the Sun. The bodies revolving around the planets are considered as satellites of the planet. Moon is the natural satellite of Earth.

Mars appears slightly reddish in colour and is also called the red planet. It has two small natural satellites.

The Sun is the star having a system of planets with one planet called Earth with life on it. The Earth is the only planet on the solar system on which the life is known to exist.

Ursa Major has seven prominent stars. Pole star can be located with the help of Ursa Major. It is located by drawing an imaginary line passing through the two stars at the end of Ursa Major. This imaginary line is extended towards the North direction, which is about five times the distance between the two lines. This line will lead to a star which is not too bright. This star is Pole star.

The constellation Orion is visible during winter in the late evenings. It also has seven or eight bright stars. It is also called the Hunter. The three middle stars represent the belt of the hunter. The four bright stars appear to be arranged in the form of a quadrilateral.

The distance between the Earth and stars and the distance between the stars is very large. The stars are millions of times farther away than the Sun. the Sun is nearly 150,000,000 Km i.e. 150 million Km away from the Earth. It is inconvenient to express these distances in kilometres. Therefore, these large distances are expressed in light years. For example, the distance of the Sun from the Earth may be said to be about 8 light minutes.

Earth is the only planet of the Solar System having life on it. The special environment conditions are responsible for the existence and the continuation of life on the Earth. These conditions include the right distance from the Sun, so it has the right temperature, the presence of water, suitable atmosphere and a blanket of ozone.

Mercury and Venus are the planets which lie between the Sun and the Earth. Mercury is the smallest planet and is very close to the Sun. Venus is the nearest planet to the Earth and is the brightest planet of the Solar System.

Asteroids are the celestial objects which are also called minor planets. Asteroids can only be seen through large telescopes.

Light year is the unit used to express distance between the various celestial bodies. Light year is the distance travelled by light in one year. The speed of light is 300,000km per second. For example, the Sun is nearly 150,000,000Km i.e. 150 million Km away from the Earth. The distance of the Sun from the Earth may be said to be about 8 light minutes. 1 light year = 9.46 × 1012Km.

Mercury and Venus shows phases like the Moon. They have the orbits which are smaller than the Earth and exhibit the full range of phases like the moon.

1. Cassiopeia is another prominent constellation in the northern sky. It is visible during winter in the early part of the night. It looks like a distorted letter W or M.
2. Leo Major is visible in the northern hemisphere around the spring. It is easily identifiable through may. Its brightest star is Regulus. Its most prominent pattern of stars is a backwards question mark called the Sickle. You can use the Pointer stars of the Big Dipper to find Leo Major.

Ursa Major is the constellation which reminds us of a large ladle or a question mark in the night sky. It is also known as the Big Dipper, the Great Bear or the Saptarshi. There are seven prominent stars in this constellation. It appears like a big ladle or a question mark.

Saturn has rings around it which makes it unique in the Solar System. These rings can be observed with a small telescope and cannot be seen with the naked eye. Saturn also has a large number of satellites.

INSAT stands for the Indian National Satellite System. It is a series of multipurpose geo-stationary satellites launched by ISRO to satisfy the telecommunications, broadcasting, meteorology, and search and rescue operations.

Venus appears in the eastern sky before sunrise. It is known as morning star. Sometimes, it appears in the western sky just after sunset. It is known as Evening star.