Chapter 16 - The Universe
1. Name these –
(a) Birthplace of stars
Ans: Nebula
(b) Biggest planet in the solar system
Ans: Jupiter
(c) The galaxy which is our neighbour.
Ans: Andromeda
(d) Brightest planet in the solar system
Ans: Venus
(e) Planet with largest number of satellites
Ans: Jupiter
(f) Planets without a single satellite
Ans: Mercury and Venus
(g) Planet with a rotation different from other planets.
Ans: Venus and Uranus
(h) A celestial body that carries a tail along.
Ans: Comets
2. Fill in the blanks.
(a) The group of galaxies of which our Milky Way is a part is called …………. .
Ans: ‘Local Group’
(b) Comets are made of …………. .
Ans: ice and dust particles.
(c) The planet …………. appears as if it is rolling along its orbit.
Ans: Uranus
(d) …………. is a stormy planet.
Ans: Jupiter
(e) The Pole Star is the best example of a …………. type of star.
Ans: variable
3. Say if the statements given below are right or wrong. Rewrite the statements after correcting them.
(a) Venus is the planet closest to the sun.
Ans: Wrong
Mercury is the planet closest to the Sun.
(b) Mercury is called a stormy planet.
Ans: Wrong
Jupiter is called a stormy planet.
(c) Jupiter is the biggest planet.
Ans: Right
4. Answer the following.
(a) What is a special characteristic of the planet Mars ?
Ans: The special characteristic of the planet Mars is that it is red in color. This is due to the presence of iron in its soil. Also, the highest and longest mountain in the solar system, “Olympus Mons,” is located on Mars.
(b) What are the types of galaxies ?
Ans: The different types of galaxies identified according to their shapes are spiral galaxies, elliptical galaxies, barred spiral galaxies, and irregular galaxies.
(c) Which celestial bodies does a galaxy include ?
Ans: A galaxy includes stars, clusters of stars, nebulae, clouds of gases and dust, dead stars, newly born stars, etc.
(d) Name the different types of stars.
Ans: There are five different types of stars:
(i) Sun-like stars
(ii) Twin stars
(iii) Supernova
(iv) Red giants
(v) Variable stars
(e) What are the types of comets and on what basis are they classified?
Ans: Comets are solar system bodies that are typically spherical in shape and develop tails when they approach the Sun.Comets become visible when they are close to the Sun and the Earth.
They can be categorized into two groups depending on how long they take to complete one revolution around the sun. These are:
(a) Long-period comets
(b) Short-period comets
(f) What is the difference between meteors and meteorites ?
Ans:
| Meteor | Meteorite |
|---|---|
Meteors do not land on the surface of the earth. | Meteorites land on the surface of the earth. |
Meteoroids break down in the earth’s atmosphere, which results in the flash of light known as a meteor. | Meteorites are fragments of meteoroids that fall to Earth. |
They are usually millimeter-sized or smaller. | Their size can range from about a fraction of a gram to 100 kilograms. |
Meteors are considered to be part of the solar system. | Meteorites originate from outer space. |
Meteors are burning rocks. | Meteorites contain a combination of metals, magnetic elements, and nickel. |
(g) What are the characteristics of the planet Neptune ?
Ans: Following are the characteristics of planet Neptune:
(i) A season on this planet lasts for about 41 years.
(ii) On this planet, the wind blows extremely fast.
5. Match the following.
| Group A | Group B |
|---|---|
(1) Galaxy | (a) From east to west |
(2) Comet | (b) 33 satellites |
(3) Sun-like star | (c) Spiral |
(4) Saturn | (d) Sirius |
(5) Venus | (e) Halley |
Ans:
| Group A | Group B |
|---|---|
(1) Galaxy | (c) Spiral |
(2) Comet | (e) Halley |
(3) Sun-like star | (d) Sirius |
(4) Saturn | (b) 33 satellites |
(5) Venus | (a) From east to west |