The Universe and Solar System Online Test – 6th Social Science Lesson 5 Questions in English

The Midnight Sun is a natural phenomenon that occurs in the summer months in places north of the Arctic Circle or south of the Antarctic Circle, when the Sun remains overhead 24 hours a day.

ISRO launched India’s first ever Moon mission, Chandrayaan - 1 in 2008.

The word ‘solar’ is derived from the Roman word ‘sol’, which means ‘Sun God’. The solar system is believed to have formed about 4.5 billion years ago.

Rotation is the spinning movement of the Earth on its axis. The Earth rotates from west to east (anticlockwise) and takes 23 hours 56 minutes and 4.09 seconds to complete one rotation. The time taken by the Earth to complete one rotation is called a day.

The inner planets are comparatively smaller in size and are composed of rocks. The surface of inner planets has mountains, volcanoes and craters.

Perihelion is the Earth’s closest position to the Sun. Aphelion is the farthest position of the Earth from the Sun.

The study of the Universe is called Cosmology. The term Cosmos is derived from the Greek word ‘Kosmos’.

A comet is a celestial object made up of a head and a tail. The head of a comet consists of solid particles held together by ice and the tail is made of gases.

The Sun is a star. It is self-luminous so it gives light on its own. 1.3 million Earths fit inside the Sun.

Mercury is the smallest and closest planet to the Sun. It has no natural satellites. It is an airless and waterless planet.

Life is possible on Earth because of the presence of land, air and water. The polar diameter of the Earth is 12, 714 km and the equatorial diameter is 12, 756 km.

Halley’s Comet is the most famous comet which comes close to the Earth every 76 years. It last appeared in 1986 and will next appear in 2061.

The velocity of the Earth’s rotation varies from 1670 km per hour at the equator to 845 km per hour at 60° N and S latitudes and zero at the poles.

The Northern Hemisphere is inclined towards the Sun for six months from 21st March to 23rd September while the Southern Hemisphere is tilted away from the Sun. From Sep 23rd to March 21st the southern hemisphere is inclined towards the Sun and the northern hemisphere faces away from the Sun.

The elliptical path in which the planets move around the Sun is known as orbit. The eight planets revolve in their respective orbits because of the gravitational pull of the Sun. They do not move out of their paths or away from the solar system.

Numerous stars and celestial bodies came into existence by a massive explosion called Big Bang. These celestial bodies together are called The Universe. It is also referred to as the Cosmos.

A Light year is the unit used to measure the distance between the celestial bodies. A light-year is the distance traversed by light in a year at a velocity of 300,000 km per second

The Sun is the source of light and heat energy to the entire solar system. Sunlight takes about 8.3 minutes to reach the Earth.

The Universe is a vast expanse of space. Light year is the unit used to measure the distance between the celestial bodies.

Jupiter is the fastest spinning planet in the solar system. It is called a gas giant planet. Its atmosphere is made up of mostly Hydrogen and Helium like the Sun.

Most astronomers believe that the Universe came into existence after the Big Bang explosion that took place about 15 billion years ago.

Venus is often visible in the mornings and the evenings and so it is frequently called as the Morning Star and the Evening Star. After the Moon, it is the brightest natural object in the night sky.

A meteor is a stone like or metallic body. As they often appear as streaks of light in the sky, they are also known as Shooting Stars.

A meteor is a stone like or metallic body. When entering into the Earth’s atmosphere, most of them burn. Meteors which strike the Earth’s surface are called meteorites.

Neptune is the eighth and the farthest planet from the Sun. There are strong winds in this planet. It is named after the Roman god of sea.

Galaxy is a huge cluster of stars which are held together by gravitational force. Most of the galaxies are scattered in space, but some remain in groups.

On 22nd December, the Tropic of Capricorn faces the Sun. It is called as Winter Solstice. It is the longest day in the Southern Hemisphere and longest night (shortest day) in the Northern Hemisphere.

Asteroids are small solid objects that move around the Sun. They are found as a belt between Mars and Jupiter. They are too small to be called as planets. They are also known as Planetoids or Minor Planets.

On 21st June, the Tropic of Cancer faces the Sun. This is known as Summer Solstice. It is the longest day in the Northern Hemisphere and longest night (shortest day) in the Southern Hemisphere.

The Sun is at the centre of the solar system. Each member of the solar system revolves around the Sun.

Uranus has 27 natural satellites, of which Titania is the largest. Its axis is tilted so much that, it appears to orbit the Sun on its sides like a rolling ball.

The striking blue and white features of Neptune help to distinguish it from Uranus.

Uranus (The Somersaulting planet) appears green due to the presence of methane. Uranus is the seventh planet from the Sun.

Uranus is the seventh planet from the Sun. It was the first to be discovered with a telescope by the astronomer William Herschel in 1781.

Saturn is the sixth planet from the Sun and the second largest planet in the solar system, after Jupiter. Saturn has 62 natural satellites around it.

The solar system is a gravitationally bound system which comprises of the Sun, the eight planets, dwarf planets, satellites, comets, asteroids and meteoroids.

The four planets nearer to the Sun are called Inner or Terrestrial Planets (Mercury, Venus, Earth and Mars).

Neptune has 14 natural satellites, the largest being Triton. Because of its distance from the Sun, Neptune is one of the coldest planets in the solar system.

Mars is named after the Roman God of war. It appears red in colour due to the presence of iron oxide on its surface. So, it is often described as The Red Planet.

Our solar system is a part of the Milky Way galaxy. Andromeda galaxy is the nearest to the Earth apart from the ‘Magellanic Clouds’ galaxy.

The distance between the moon and the Earth is about 3, 84,400 km. The size of the moon is one-quarter of the Earth. The Moon is the only celestial body where humans have landed.

The word planet means wanderer. There are eight planets in the solar system. They are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

Most of the galaxies are scattered in space, but some remain in groups. Milky Way Galaxy was formed about 5 billion years after the Big Bang explosion.

The Earth is the third planet from the Sun and the fifth largest planet in the solar system. It is called ‘blue planet’ or ‘watery planet’ because three-fourth of the Earth is covered by water.

Venus (The Hottest Planet) has the longest rotation period (243 days) among the planets in the Solar system.

The Moon - Earth’s Satellite has no atmosphere. The surface of the moon is characterized by craters created by the impact of meteors.

Jupiter has the largest number of natural satellites. Io, Europa, Ganymede and Callisto are a few large satellites of Jupiter.

Jupiter is the fifth planet from the Sun and the largest planet in the solar system. It is the third brightest object in the night sky, after moon and Venus.

The Earth revolves around the Sun at a speed of about 30 km per second. The only natural satellite of the Earth is the Moon.

The specific gravity of Saturn is less than that of water. If you could put Saturn in a large enough ocean it would float.

The last four planets are also called Gaseous Giants. An asteroid belt is found between Mars and Jupiter.

Saturn is named after the Roman god of agriculture. Saturn has many rings around it. Saturn is the sixth planet from the Sun and the second largest planet in the solar system, after Jupiter.

Venus is the second planet from the Sun. It is named after the Roman goddess of love and beauty.

Venus rotates in the opposite direction to all other planets except Uranus. It has no natural satellites like Mercury.

The Sun is a huge star. Sun is so huge that it accounts for 99.8 percent of the entire mass of the solar system.

Mars is the fourth planet from the Sun and the second smallest planet in the solar system, after Mercury.

The word lithosphere is derived from the Greek word Lithos, which means rocky. The Lithosphere is the land on which we live. It is the solid outer layer of the Earth consisting of rocks and soils.

The illuminated portion of the Earth experiences day, whereas the darkened part of the Earth experiences night. The line which divides the surface of the Earth into a lighted half and a dark half is called the Terminator Line.

Mercury is the smallest and closest planet to the Sun. It is named after the Roman deity ‘Mercury’, the messenger to the Gods.

All the planets rotate anti-clockwise (from west to east) on their own axes except Venus and Uranus. Hence remaining Neptune

Mercury can be viewed in the morning and evening with naked eye. It does not have an atmosphere and so experiences extremes of temperature

Venus is the second planet from the Sun. It is called Earth’s twin, as it is almost the same size as the Earth.

The major gases are Nitrogen (78%) and Oxygen (21%). The other gases like Carbon dioxide, Hydrogen, Helium, Argon, and Ozone are present in meager amounts.

A light-year is the distance traversed by light in a year at a velocity of 300,000 km per second. Sound travels at a speed of 330 m per second.

Mercury can be viewed in the morning and evening with naked eye. It does not have an atmosphere and so experiences extremes of temperature

The Earth’s axis is always tilted or inclined from the vertical by an angle of 23½°. It makes an angle of 66½° with the plane of the Earth’s orbit.

Mars has a thin atmosphere. It also has polar ice caps like the Earth. Mars has two natural satellites namely Phobos and Deimos. Many orbiters and rovers have been launched to explore this planet.

Satellites are celestial objects, which revolve around the planets. The moon is the Earth’s only satellite. It revolves around the Earth once in every 27 days and 8 hours.

Dwarf planets are small celestial bodies found beyond the planet Neptune. They are extremely cold and dark. They are almost spherical in shape, but unlike planets they can share their orbit with other dwarf planets.

The Gulf of Mannar Biosphere Reserve in the Indian Ocean covers an area of 10,500 sq.km in the ocean.

The narrow belt of interaction among the lithosphere, the hydrosphere and the atmosphere, where life exists is known as Biosphere. Bio means life in Greek.

Mercury is an airless and waterless planet. It does not have an atmosphere and so experiences extremes of temperature.

The Northern Hemisphere is inclined towards the Sun for six months from 21st March to 23rd September while the Southern Hemisphere is tilted away from the Sun.

The five dwarf planets of the solar system are Pluto, Ceres, Eris, Makemake and Haumea. Dwarf planets are small celestial bodies found beyond the planet Neptune.

The equator faces the Sun directly on 21 March and 23 September. These two days are called Equinoxes, during which the day and night are equal throughout the Earth.

The distance between the Sun and the Earth is about 150 million kilometres. A flight flying at a speed of 800 km per hour from the Earth would take 21 years to reach the Sun.

The Sun is made up of extremely hot gases like Hydrogen and Helium. The surface temperature of the Sun is about 6,000° C.

Saturn has many rings around it. These rings are huge and are mostly made up of ice, rocks and dust particles.

The Earth is the only planet in the solar system which is not named after any Greek or Roman deity. It is the only planet known to support life.

Uranus (The Somersaulting planet) is named after the Greek god of the sky. It rotates on its axis from east to west like Venus.