6) Space Physics

Question 1

Define Rotation of Earth:

Answer 1

The circular movement of the Earth about its own axis is called as the rotation of the Earth.

Question 2

Define Average orbital speed:

Answer 2

It is defined using the equation: v = 2??r /T where r is the average radius of the orbit and T is the orbital period

Question 3

Define Solar system

Answer 3

Solar system is a single term that includes eight planets and their moons in orbit round the sun. Also included in the solar system are the smaller bodies such as the comets., asteroids, and the meteoroids.

Question 4

Define Orbital distance:

Answer 4

Orbital distance is the term that tells us the time taken by one object to revolve around the other.

Question 5

Define Orbital duration[ Orbital time}:

Answer 5

Orbital duration is the time taken by one object to completely orbit around the other.

Question 6

Define gravitational field strength:

Answer 6

Gravitational field strength is a term that indicates the amount of gravitational force that is exerted per unit mass at a particular point.It has a symbol “g”

Question 7

Define Interstellar clouds of gas and dust:

Answer 7

It is a cloud comprising of dust, plasma and gases present in all the galaxies, including our own.

Question 8

Define accretion disc

Answer 8

These are structures that surround the celestial objects such as the stars and the black holes.These structures are made of gas, plasma and dust

Question 9

Define Planetary data:

Answer 9

It refers to the data that gives us information on the different planets based on researches and explorations

Question 10

Define Stars:

Answer 10

Stars are massive , self-luminous celestial objects, made of Hydrogen and Helium

Question 11

Define Proto stars:

Answer 11

A protostar is a young star. .It is formed as a result of accretion in the nebula.

Question 12

Define Stable stars:

Answer 12

In every star, there is the gas pressure that exerts an outward force from the centre and at the same time , there is gravity that is pulling the atoms of Hydrogen and Helium inwards. When the outward pushing force balances the gravitational force, we call the star as a stable tar.Example of a stable star is the Sun.

Question 13

Define Sun:

Answer 13

The Sun is a very bright, luminous, celestial and a stable star, situated in the spiral arm of the Milky Way galaxy and at the centre of the Solar System.

Question 14

Define Galaxy:

Answer 14

The word galaxy encompasses billions of stars along with their solar systems,gas and dust held by their gravity. There are more than a hundred billion galaxies in the universe.

Question 15

Define Milky way:

Answer 15

Milky way is a spiral galaxy that includes our solar system. It has billions of stars, including our Sun.

Question 16

Define Universe:

Answer 16

Universe refers to the space, time and matter and all the laws that govern them.

Question 17

Define Light-year

Answer 17

One light-year is the distance traveled in (the vacuum of) space by light in one year.

Question 18

Define Red giants

Answer 18

These are massive , luminous stars with a very low surface temperature and a high volume , with a reddish-orange hue, in their final stage of stellar evolution and that have exhausted their supply of Hydrogen in their core.Examples: Aldebaran (Alpha Tauri) and Mira (Omicron Ceti).

Question 19

Define Red supergiants:

Answer 19

Red supergiants are aging giant stars with a minimum of 15 solar masses. [solar mass refers to the mass of the sun, when used as a unit of mass. One solar mass is equal to 1.989 x 1030 kg ]

Question 20

Define Supernova:

Answer 20

Supernova is a powerful and luminous stellar explosion, that happens when a star has reached the end of its life.Example: Kepler’s Supernova

Question 21

Define Nebula:

Answer 21

Nebula is a Latin word for fog or cloud.It consists of interstellar clouds consisting of Helium, Cosmic Dust, ionised gases, hydrogen as well as molecular clouds. [There are in all 5 different types of Nebulae, namely;emission nebulae, reflection nebulae, dark nebulae, planetary nebulae, and supernova remnants.

Question 22

Define Black hole:

Answer 22

A black hole is a region in the space, in which the effect of gravity is so strong, that it lets nothing escape out f it, not even light.The region appears to be black and circular.[ There are approximately 100 billion super massive black holes]

Question 23

Define Redshift:

Answer 23

Redshift is a phenomenon in which the spectrum of an astronomical object gets displaced towards the longer( red) wavelength.

Question 24

Define Cosmic microwave background radiation (CMBR):

Answer 24

Cosmic microwave background radiation (CMBR) is the leftover of the cosmic radiation after the big bang.

Question 25

Define Hubble constant Ho:

Answer 25

Hubble constant is the ratio of the speed at which the galaxy is moving away from the Earth to its distance from the Earth