Last updated on June 28th, 2023 at 11:09 pm
Class 8 Stars and The Solar System Extra Question Answers
Que: Why is Earth a unique planet?
The Earth is not so hot not so cold. Water and air are essential for life on the planet for our survival. Air contains gases like oxygen that sustain life. These reasons make Earth unique among the planets in our solar system.
Que: Why do stars give out heat and light?
Stars are huge spinning balls of glowing gas. Hydrogen atoms combine to form helium at the center of stars. A huge amount of energy is released in this process in the form of light and heat.
Que: What is a light-year? Give its value.
Light-years are units of distance. A light-year is the distance light can cover in one year. Each second, light travels at a speed of about 300,000 kilometers (km). Therefore, one year’s light travels approximately 10 trillion kilometers. 1 light-year = 9,500,000,000,000 kilometers.
Que: What is a comet? Why does it show a long tail when it reaches near the Sun?
Comets are objects that are made up of frozen gases, dust, and rock and travel around the Sun in an elongated orbit. The gases present on the surface of the comet begin to glow when it approaches the Sun As the comet evaporates, it resembles a glowing ball with a long tail away from the direction of the Sun.
Que: Write down the names of some constellations.
The three constellations are Ursa Major, Ursa Minor, and Orion.
Que: Why is Mercury so hot during the day and so cold at night?
Since it is very close to the Sun, it is very hot during the day and very cold at night.
Que: What are the uses of artificial satellites?
Artificial satellites are used for weather forecasting, long-distance communication, and remote sensing.
Que: Why pole star appears stationary?
The pole star appears to be stationary from the Earth because it is situated close to the direction of the axis of rotation of the Earth.
Define the following terms:-
Constellation:- The stars forming a group that has a recognizable shape is called a constellation.
Asteroid:- Large pieces of rock or metal that revolve around the sun are called asteroids.
Phases of Moon:- en viewed from Earth, the moon appears to change shape from one night to the next. This is due to the fact that the Sun, Earth, and Moon’s relative positions change on a daily basis. The various shapes of the bright part of the moon as seen during a month are called phases of the moon
Artificial Satellite:-An artificial satellite is a man-made object orbiting the earth in outer space.
Celestial Object:- The stars, the planets, the moon, and many other objects in the sky are called celestial objects.
Astronomy: – The study of celestial objects and associated phenomena is called astronomy.
Orbit:- A planet has a definite path in which it revolves around the Sun. This path is called an orbit.
Meteors:- When the sky is clear and the moon is not present, you may sometimes see bright streaks of light in the sky. These are not stars but are commonly known as shooting stars also called meteors.
Meteorite:- Some meteors reach the Earth before they completely evaporate. The body that reaches the Earth is called a meteorite.