Geography [1 Mark Question Answer]

Mercury

Pluto

Jupiter and Saturn

Mercury and Venus

Neptune is not inhabitable because of very low surface temperature (-216°C) and methane clouds surrounding it.

Venus is not inhabitable because its atmosphere contains 96% of carbon dioxide and the temperature reaches a maximum of 480°C. It is the hottest planet in the solar system.

Titan, one of the 22 satellites of Saturn is the largest known satellite of any planet. Its size is larger than mercury and is surrounded by an atmosphere of nitrogen vapours.

There are 57 known satellites in our Solar System.

Planets are an opaque heavenly body. They radiate no light of their own but shine with the light that is reflected from the Sun.

There are several galaxies in the limitless universe. Each galaxy consists of millions of stare like the Sun. Thus, the Sun is an ordinary star in no way different from many of the other stars.

Earth and its Moon are called a double planet because they revolve around the sun nearly in one and the same orbit.

Because the Earth is the only planet that has water and 70% of its surface is covered by water.

The Moon is the only satellite of the Earth.

The Earth is the third planet of the Solar System. Its position lies between Venus and Mars. It is a spheroid.

Venus is similar to the Earth in size, weight, and density. Both the planets are very close to each other because of its similarity to the Earth, Venus is called ‘Earth’s Twin

Mercury is the smallest planet and the closest to the Sun. It takes only 88 days to orbit the Sun. It has a thin atmosphere. Due to its nearness to the Sun, it is the hottest planet.

The shape of the earth is not exactly that of a sphere due to the centrifugal force created by the rotation of the earth around its own axis.

The moon appears big in the sky though it is smaller than other heavenly bodies because it is nearest to the earth than other heavenly bodies.

The first four-planet in order of their distance from the Sun, Mercury, Venus, Earth, and Mars are called terrestrial planets, because of their similarity with the Earth.

The Comets appear very rarely because the orbits of the comets are very large and highly eccentric.

Pluto is the farthest planet in the Solar System, so it is deadly colder. It is about 40 times farther from the Sun than the Earth.

Venus is similar to the earth in size, weight, and density. Both the planets are very close to each other. Because of its similarity to the Earth, Venus is called ‘Earth’s Twin.

15.8 light year

 The unit adopted for measuring the distances in the universe is the light year. The reason for the choice of this unit is that a kilometer is too short a unit to measure the distances between one heavenly body and another in space.

Two sources of heat in the interior of the earth are the radioactive elements trapped inside and the immense temperature and pressure in the deep interior.

The conditions necessary for life on earth, are ideal temperature range with an average between 10°C and 35°C, solar radiation, humidity, wind, water, land, etc.

The biosphere is the narrow zone of contact amidst the lithosphere, hydrosphere, and atmosphere.

The earth is called a watery planet, as its major part i.e. 70% is covered by water or hydrosphere. The earth is seen blue in the satellite pictures due to the majority of the water.

The earth’s mean temperature is 17° C, which is ideal to support the survival of the life-system.

Our earth is also called a Tonely-planet’ because of its one important aspect of having an extensive life system.

The sun is a star or a ball of hot gases. Its diameter is 1,392,000 km. i.e. 110 times larger than that of earth and its volume is 1.3 million times larger than the earth.

The inner planets are called the terrestrial planets because their structure is similar to that of the earth.

The planets that lie within the asteroid belt that is Mercury, Venus, Earth, and Mars are called the inner planets.

A planet is a rocky or gaseous mass that revolves around a star.

On the surface of the earth, there are continents and oceans. The life on the continents or on land is called ‘Terrestrial Life’.

Mercury and Venus.

Third

Neptune

Mercury

Jupiter.

Eight

One second approximately.

(a) Presence of atmosphere
(b) Presence of water

Sun’s light is reflected from the surface of the moon.

8 minutes approximately.

27 days 7 hours 43 minutes.

Sun

100 approximately.

Venus