Stars and Solar System

Q61. How long does it take sunlight to reach the Earth?

Ans. It takes sunlight an average of 8 minutes and 20 seconds to travel from the Sun to the Earth.

Q62. What characteristics of Mars distinguish it from other planets?

Ans. Mars appears slightly reddish and, therefore, it is also called the red planet. Mars has two small natural satellites.

Q63. Which constellation appears like a big ladle or a question mark?

Ans. Ursa Major appears like a big ladle or a question mark. It is also known as the Big Dipper, the Great Bear or the Saptarshi.

Q64. Which is the nearest star to earth, after the sun?

Ans. Alpha Centauri is the nearest star to earth, after the sun. It is at a distance of about 40,000,000,000,000 km from the Earth.

Q65. What is a constellation? Name any two constellations.

Ans. The stars forming a group that has a recognisable shape is called a constellation. Two constellations are Ursa Major and Orion.

Q66. Name the constellation which appears to have the shape of a big bear.

Ans. Ursa Major is the constellation which appears to have the shape of a big bear. It is also known as the Big Dipper, the Great Bear or the Saptarshi.

Q67. In which part of the sky can you find Venus if it is visible as an evening star?

Ans. Sometimes Venus appears in the western sky just after sunset. Therefore it is often called an evening star, although it is not a star.

Q68. Which agency is responsible for the development of space science programs in India?

Ans. Indian Space Research Organization (ISRO) is the agency responsible for the development of space science programs in India.

Q69. What is solar system?

Ans. 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.

Q70. What is the simplest method of identifying planets from stars?

Ans. The simplest method of identifying planets from stars is that stars twinkle, whereas planets do not. Also the planets keep changing their positions with respect to the stars.

Q71. What are planets?

Ans. The planets look like stars, but they do not have light of their own. They merely reflect the sunlight that falls on them. A planet has a definite path in which it revolves around the Sun.

Q72. What are meteors?

Ans. At night, when the sky is clear and the moon is not there, we may sometimes see bright streaks of light in the sky. These are commonly known as shooting stars, although they are not stars. They are called meteors.

Q73. Which star has a system of planets with life on one of its planets?

Ans. The Sun is the star which has 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.

Q74. What are uses of artificial satellites?

Ans. Artificial satellites have many practical applications. They are used for forecasting weather, transmitting television and radio signals. They are also used for telecommunication and remote sensing.

Q75. What are inner planets?

Ans. The first four planets, Mercury, Venus, Earth and Mars are much nearer the Sun than the other four planets. They are called the inner planets. The inner planets have very few moons.

Q76. What is a Meteor Shower?

Ans. When the Earth crosses the tail of a comet, swarms of meteors are seen. These are known as meteor showers. Some meteor showers occur at regular intervals each year.