The Universe || Class 9 Science Notes

THE UNIVERSE

1. Short answer type questions: 

a. Define the universe.

= The universe is each and every thing existing on or beyond the earth which consists of less than 5% visible bodies and about 95% dark matter and dark energy.

b.What are the major components of the universe?

= The major(Main) components of the universe are: 

i Dark matter. 

ii. Dark energy

c.What is the delicate equilibrium of a star?

= The delicate equilibrium of a star is the equilibrium between the inner energy (gravity) and the outer energy (nuclear) of a star. 

d. Define a black hole.

= A black hole is a massive dead star that has great amount of matter packed into a very small area.

e. What will the sun look like when this phase of its life cycle is over?

= Following this phase of its life cycle, the sun will transform into a white dwarf.

g. What makes up the universe's black matter?

= The universe's "dark matter" is a black hole.

h. Which celestial body experiences a supernova explosion?

= Red Super Gaint heavenly body explodes in the form of supernova.

i. Define light year. 

= The distance covered by light in one year is called (LY) light year.

j. How many kilometers astronomical unit? 

= 1.5x10^8 kilometers are equivalent to 1 astronomical unit.          

k. How many light years are equivalent parsec? 

→3.26 light years are equivalent to 1 parsec.

2. Long answer type questions: 

a. Derive that LY is equivalent to 9.46 x 10^12 km.

= Solf,

    LY = distance covered by light in year 

          =Speed of light x time

          =3x10 km/s x 365 d x 24hx60m x 60s. 

          =3x10 km/s x31536000s

          =94608000x10 km. 

          =9.46×10 km proved.

b. Define parsec with its value in km. 

= A parsec is that distance at which the mean range of the world's circle frames a point of "1 bend. It esteem in km is 3.08x10^13km.

c. Describe nebula as a star nursery. 

→ The term "nebula" refers to the massive cloud of dust and gas in the region between the stars. Nebulae are created from the gas and dust released by a supernova explosion. Nebulae are also known as star nurseries since they are the places where new stars are born.

d. How star born in a nebula? Describe the process clearly.

→ Nebulae come from the and dust thrown gas-out by the explosion of a super-nova. Much of the gas in nebulae is made up of hydrogen and helium. In a nebula, the dust and very gases are less dense because to gravity. can start to bring them together gradually. The scenario of producing new stars and star birth in a nebula results from the gravitational lumps' increasing size and gravitational strength.

e. Describe the hole of formation of black hole.

→ A black hole is an extremely dense concentration of stuff. Supernovas are explosions of stars caused by the discharge of enormous energy. After the cosmic explosion occurs, if there are still three suns left, it creates a multi-sun powered dark opening with such extreme gravity that even light cannot escape. be further framed by the collision of two neutron stars.

f. Briefly explain the role played by national organizations in astronomy promotion.

= "Cosmic revelations spellbind the human creative imagination by relating to significant and enduring questions about our origins and the concept of the cosmos in which we dwell Awareness," said the poet of the limitlessness of the universe, the remarkable structure that different universes can accept, and the spot of our home planet in existence move Lander in individuals, everything being equal. Suitable accounting of the benefits of large NASA space-based public interest. The logical accomplishments of NASA's space missions have garnered a great deal of interest from NSF ground-based cosmology offices, and this interest has been sustained by creatively presented and well supplied appropriated insight into these accomplishments.

g. Describe the role of international agencies in the promotion of astronomy in short.

= The Global Galactic Association (IAU) was established in 1919. Its main goal is to advance and shield the study of cosmology in the entirety of its perspectives, including research correspondence schooling and improvement, through worldwide collaboration.