Basic Science Solutions for Class 8 Science Chapter 13 Our Universe are provided here with simple step-by-step explanations. These solutions for Our Universe are extremely popular among class 8 students for Science Our Universe Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the Basic Science Book of class 8 Science Chapter 13 are provided here for you for free. You will also love the ad-free experience on Meritnation’s Basic Science Solutions. All Basic Science Solutions for class 8 Science are prepared by experts and are 100% accurate.

Page No 145:

Answer:

Light year is a unit of distance. It is defined as the distance travelled by light in one year.

Page No 145:

Answer:

The source of the star's energy is the reaction in which hydrogen gas is converted into helium. In this reaction, a huge amount of energy is liberated.

Page No 145:

Answer:

The difference in the distribution of stars in the galaxies gives the galaxies different shapes. Some of the shapes of galaxies are spiral, ring or elliptical.

Page No 145:

Answer:

The seven brightest stars of the Ursa major form the shape of a dipper and the constellation is called the Big Dipper or Saptarshi.

Page No 145:

Answer:

Mercury, Venus and Mars are called terrestrial planets because they are like Earth. They are the closest to the sun and they have rocks.

Page No 145:

Answer:

The gas giants or Jovian planets have a ring around them. These planets include Saturn, Jupiter, Uranus and Neptune.

Page No 145:

Answer:

The huge spot on Jupiter is a huge storm that has been raging on it for more than 300 years.

Page No 145:

Answer:

Ceres and Eris are two dwarf planets.

Page No 145:

Answer:

A dwarf planet is different from a planet as it was not able to pull in the objects near its orbit at the time of its formation.

Page No 145:

Answer:

Stars Planets
They twinkle. They do not twinkle.
They emit their own light. They do not emit their own light.
They do not change their positions. They keep changing their positions.

Page No 145:

Answer:

Galaxy Constellation
It is a group of stars and other celestial bodies held together by gravitational force. It is a group of stars that form a particular pattern.
Galaxies are real. Constellations are imaginary.



Page No 146:

Answer:

The given pattern of stars belongs to the Great Bear or Ursa Major.
The two stars of this constellation used by travellers to locate the pole star are called pointers.

Page No 146:

Answer:

The small, rocky bodies that revolve around the sun between the orbits of Mars and Jupiter in a belt are called asteroids or minor planets. This belt is known as an asteroid belt. Asteroid belts can range from a few metres to hundreds of kilometres in width. Some of them also have moons. They are thought to be the pieces of materials that were not able to join together to form a planet during the formation of the solar system.

Page No 146:

Answer:

Those rocks that orbit the sun are called meteoroids. They burn on entering the earth's atmosphere, emitting a streak of light. Meteoroids that fall on a planet or a moon are called meteorites. Meteorite craters are more commonly found on those planets and moons that have little or no atmosphere to burn them. Thus, the meteorites hit the surface of these planets creating large craters.

Page No 146:

Answer:

A small body of ice and dust that moves around the sun in an elongated path is known as a comet. Its tail is formed by the glowing gases and dust that are left behind the comet when it heats up on approaching the sun.

Page No 146:

Answer:

Life on Earth is possible due to following conditions:

(a) Its distance from the sun. If it had been nearer to the sun, all the water would have evaporated and if it had been too far from the sun, all the water would have frozen.
(b) The composition of its atmosphere. Carbon dioxide is present in the atmosphere and is used by plants to make food for themselves and other animals. It also traps the appropriate amount of heat required to warm the Earth.
(c) Plenty of water in its liquid form exists on Earth.

Page No 146:

Answer:

The appearance of the Moon changes due to its revolution around the Earth. The portion of the Moon on which sunlight falls is lit up. As the Moon revolves around the earth, sunlight falls on different parts of the Moon, giving the impression that the Moon is changing shapes. These changing shapes that we see are the phases of the moon. It takes 28 days and eight hours to complete one revolution of the Moon. A full moon occurs when the whole side of the Moon facing the Earth is lit by the Sun whereas if the side of the Moon facing the Earth gets no sunlight, then it is called as a new moon. After the new moon, the size of the Moon gradually increases till the full moon after which it starts decreasing till the new moon.

Page No 146:

Answer:

1. The explosion that created the universe is called the big bang.
2. Scientists recently detected a newborn star 100 light years away. Light from this star takes 100 years to reach the Earth.
3. The stars seem to move across the sky from east to west.
4. The Milky Way Galaxy is spiral in shape.
5. The Sun is able to keep the bodies of the solar system together because of its gravitational force.
6. The giant planets of our solar system are made up mainly of gases.
7. Venus is hotter than Mercury because of the carbon dioxide in its atmosphere.
8. Ganymede, the largest moon of the solar system, is even larger than the planet Mercury.



View NCERT Solutions for all chapters of Class 8