Universe

Question 1

Who proposed the heliocentric model (heltos Sun), with Sun at the centre of the solar system.

Answer 1

Nicolaus Copernicus

Question 2

Nearly all of the matter in the universe that we understand is made of ___________, the simplest elements, created in the Big Bang

Answer 2

hydrogen and helium

Question 3

Which galaxy is our closest neighboring galaxy

Answer 3

Andromeda

Question 4

Our solar system is _______ away from the centre of our galaxy.

Answer 4

25,000 light years

Question 5

Just as the Earth goes around the Sun, the Sun goes around the centre of the galaxy and it takes ______ years to do that.

Answer 5

250 million

Question 6

_______ are the fundamental building blocks of galaxies.

Answer 6

Stars

Question 7

The brightness of a star depends on their ___________ from the Earth

Answer 7

intensity and the distance

Question 8

Stars also appear to be in different colours depending on their ______

Answer 8

temperature

Question 9

Hot stars are __________ whereas cooler stars are _________ in colour.

Answer 9

white or blue,
orange or red

Question 10

A group of stars forms an imaginary outline or meaningful pattern on the space. They represent an animal, mythological person or creature, a god, or an object. This group of stars is called

Answer 10

constellations

Question 11

People in different cultures and countries adopted their own sets of constellation outlines. There are ______ formally accepted constellations. Aries, Gemini, Leo, Orion, Scorpius and Cassiopeia are some of the constellations.

Answer 11

88

Question 12

Sun has hydrogen and helium of _____ ratio

Answer 12

3:1

Question 13

The period of rotation of earth

Answer 13

23 hrs 56 mins

Question 14

Mercury

Answer 14

58.65 days

Question 15

Venus

Answer 15

243 days

Question 16

Earth

Answer 16

23.93 hrs

Question 17

Mars

Answer 17

24.62 hrs

Question 18

Jupiter

Answer 18

9.92 hrs

Question 19

Saturn

Answer 19

10.23 hrs

Question 20

Uranus

Answer 20

17 hours

Question 21

Neptune

Answer 21

18 hours

Question 22

Farther from the Sun is the outer solar system, where the planets are much more spread out. Thus the distance between Saturn and Uranus is much ___________ than the distance between the Earth and the Mars.

Answer 22

greater (about 20 times)

Question 23

The four planets grouped together in the inner solar system are Mercury, Venus, Earth and Mars They are called inner planets. They have a surface of solid rock crust and so are called _________,

Answer 23

terrestrial or rocky planets

Question 24

The four large planets Jupiter, Saturn, Uranus and Neptune spread out in the outer solar system and slowly orbit the Sun are called outer planets. They are made of hydrogen, helium and other gases in huge amounts and have very dense atmosphere. They are known as __________ The four outer planets Jupiter, Saturn, Uranus and Neptune have rings whereas the four inner planets do not have any rings

Answer 24

gas giants and are called gaseous planets)

Question 25

Mercury can be easily observed thorough ________ than naked eye

Answer 25

telescope It always appears in the eastern horizon or western horizon of the sky

Question 26

After our moon, it is the brightest heavenly body in our night sky. This planet spins in the opposite direction to all other planets. So, unlike Earth, the Sun rises in the west and sets in the east here.

Answer 26

Venus Venus can be seen clearly through naked eye. It always appears in the horizon of eastern or western sky.

Question 27

Mars has two small natural satellites

Answer 27

(Deimos and Phobos).

Question 28

Jupiter is called as Giant planet. It is the largest of all planets (about _____ times larger and ______ times heavier than Earth).

Answer 28

11 318

Question 29

. It has ____ rings and _____ moons

Answer 29

3 and 65(as 2023 Jupiter has 95 moon )

Question 30

Its moon _____ is the largest moon of our solar system.

Answer 30

Ganymede

Question 31

______ appears yellowish in colour. It is the second biggest and a giant gas planet in the outer solar system.

Answer 31

Saturn

Question 32

At least ______ moons are present at saturn

Answer 32

60

Question 33

_____ is the only moon in the solar system with clouds.

Answer 33

Titan Largest moon in saturn

Question 34

______ Having least density of all (30 times less than Earth), this planet is so light.

Answer 34

Saturn

Question 35

Uranus has the longest summers and winters each lasting ____.

Answer 35

42 years

Question 36

Neptune has _____ moons . ____ being the largest.

Answer 36

13 Triton

Question 37

_______ is the only moon in the solar system that moves in the opposite direction to the direction in which its planet spins.

Answer 37

Triton

Question 38

The biggest asteroid is ______&________ km across.

Answer 38

Ceres - 946

Question 39

________ are lumps of dust and ice that revolve around the Sun in highly elliptical orbits. Their period of revolution is very long

Answer 39

Comets

Question 40

One such comet is ________ Comet, which appears after nearly every 76 years. It was last seen in 1986. It will next be seen in 2062.

Answer 40

Halley's

Question 41

They are small pieces of rocks scattered throughout the solar system Most of them are burnt up by the heat generated due to friction in the Earth's atmosphere. They are called

Answer 41

meteors

Question 42

Some of the bigger meteors may not be burnt completely and they fall on the surface of Earth These are called .

Answer 42

meteorites

Question 43

A body moving in an orbit around a planet is called .

Answer 43

satellite

Question 44

The Sun travelling at a speed of 250 km per second (9 lakh km/h) takes about 225 million years to complete one revolution around the Milky Way. This period is called a

Answer 44

cosmic year.

Question 45

The first artificial satellite Sputnik was launched in .

Answer 45

1956

Question 46

India launched its first satellite Aryabhatta on

Answer 46

April 19, 1975

Question 47

The horizontal velocity that has to be imparted to a satellite at the determined height so that it makes a circular orbit around the planet is called

Answer 47

orbital velocity.

Question 48

the satellite stays over the same spot all the time, this kind of orbit is called '.

Answer 48

geostationary

Question 49

Orbital velocity can be calculated using the following formula

Answer 49

v=√{(GM)/(R+h)} G = Gravitational constant (6.673 × 10^-11 Nm^2kg-²) M = Mass of the Earth (5.972 x 10^24 kg) R = Radius of the Earth (6371 km) h Height of the satellite from the surface of the Earth.

Question 50

Can you calculate the orbital velocity of a satellite orbiting at an altitude of 500 km? Data: G=6.673 x 10-" SI units; M=5.972\times10^{24}kg h=500000m R=6371000m

Answer 50

Ans: v=7613 ms^-1 or 7.613 kms^-1

Question 51

________ is the condition in which people or objects appear to be weightless. The effects of microgravity can be seen when astronauts and objects float in space. Micro- means very small, so microgravity refers to the condition where gravity 'seems' to be very small.

Answer 51

Microgravity

Question 52

Time taken by a satellite to complete one revolution round the Earth is called .

Answer 52

time period T=2πr/v 2π(R+h) T= ------------- √{(GM)/(R+h)}

Question 53

At an orbital height of 500 km, find the orbital period of the satellite.

Answer 53

T= 5667 s T=~95min

Question 54

All stars appear to us as moving from east to west, where as there is one star which appears to us stationary in its position. It has been named as Pole star. The pole star appears to us as fixed in space at the same place in the sky in the north direction

Answer 54

because it lies on the axis of rotation of the Earth which itself is fixed and does not change its position in space. It may be noted that the pole star is not visible from the southern hemisphere.

Question 55

Kepler was able to summarize the carefully collected data of his mentor,

Answer 55

Tycho Brahe

Question 56

Kepler First Law - The Law of Ellipses

Answer 56

All planets revolve around the Sun in elliptical orbits with Sun at one of their foci.

Question 57

Second Law - The Law of Equal Areas

Answer 57

The line connecting the planet and the Sun covers equal areas in equal intervals of time

Question 58

Third Law - The Law of Harmonies

Answer 58

The square of time period of revolution of a planet around the Sun is directly proportional to the cube of the distance between sun and the planets.

Question 59

As great as the ISS' scientific achievements are, no less in accomplishment is the international co-operation which resulted in the construction of the ISS. An international collaboration of five different space agencies of 16 countries provides, maintains and operates the ISS. They are: _________ are also part of the consortium.

Answer 59

NASA (USA), Roskosmos (Russia), ESA (Europe), JAXA (Japan) and CSA (Cananda). Belgium, Brazil, Denmark, France, Germany, Italy, Holland, Norway, Spain, Sweden, Switzerland and the UK

Question 60

The period of revolution of planet A around the Sun is 8 times that of planet B. How many times is the distance of planet A as great as that of planet B?

Answer 60

4

Question 61

The Big Bang occurred ______years ago.

Answer 61

(a) 13.7 billion

Question 62

The speed of Sun in km/s is

Answer 62

250 km/s

Question 63

The rotational period of the Sun near its poles is

Answer 63

36 days

Question 64

4. The third law of Kepler is also known as the Law of

Answer 64

Harmonics