Stars

Question 1

Define a planet

Answer 1

An object in orbit around a star with a mass large enough for its own gravity to give it a round shape that does not undergoes fusion and that has cleared its orbit of most other objects.

Question 2

planetary satellite

Answer 2

a body in orbit around a planet

Question 3

Define a comet

Answer 3

A small irregular body made of dust, ice and rock that orbits a star with a highly eccentric elliptical orbit

Question 4

Define solar system

Answer 4

A planetary system consisting of one star and at least one planet in orbit around it.

Question 5

Define galaxy

Answer 5

A collection of stars and interstellar dust and gas bound together by their mutual gravitational attraction

Question 6

Planets are defined by a series of characteristics. Identify all the statements from below that are used to characterise a planet

A Its mass is large enough for its own gravity to give it a round shape
B It has an oxygen-based atmosphere
C It has at least one moon
D It orbits a star
E It has cleared its orbit of most other objects
F It has no fusion reactions
G It has a highly elliptical orbit
H It has liquid water present on its surface

Answer 6

A planet is a body that orbits around a star and has the following 3 characteristics:

1. Its mass is large enough for its own gravity to give it a round shape
2. It has cleared its orbit of most other objects
3. It has no fusion reactions

The other options are not necessary characteristics of planets

Question 7

Identify the correct definition of a solar system

A A solar system is the collective name for a star and all the objects that orbit that star, including planets and asteroids only
B A solar system is the collective name for a star and all the objects that orbit that star, including planets, comets, and asteroids
C A solar system is the collective name for at least two stars in orbit around each other, and all the objects that orbit those stars, including planets, comets, and asteroids
D A solar system is the collective name for at least two stars in orbit around each other, and all the objects that orbit those stars, including planets and asteroids only

Answer 7

B. A solar system is the collective name for a star and all the objects that orbit that star, including planets, comets, and asteroids

Question 8

Identify the correct definition of the universe

A The universe is everything except black holes
B The universe is everything — from matter to energy and all of space-time
C The universe is everything except wormholes and black holes
D The universe is everything outside of our galaxy

Answer 8

B The universe is everything — from matter to energy and all of space-time

Question 9

Define the astronomical unti au

Answer 9

The mean distance of the Earth to the sun

Question 10

Define the Big Bang Theory

Answer 10

The theory that the universe originated as a small dense and hot region that expanded and cooled forming the structures in the universe we see today

Question 11

Chandrasekhar limit definition

Answer 11

The maximum mass that a white dwarf can have whilst remaining stable

Question 12

Define continuous spectrum and give an example of one

Answer 12

A spectrum that covers a full range of frequencies without any gaps. The electromagnetic spectrum is an example of a continuous spectrum

Question 13

State the definition of the cosmology principle

Answer 13

A principle stating that the universe is isotropic and homogenous

Question 14

Define Dark Energy

Answer 14

An energy that is responsible for the acceleration in the expansion of the universe which cannot be explained by any observable energy

Question 15

Define Doppler Effect

Answer 15

The apparent change in the wavelength of a wave as the source moves relative to an observer. For a source moving away the wavelength increases and vice versa

Question 16

Define electron degeneracy pressure

Answer 16

The outwards force, resisting the inwards force of gravity, produced asa result of multiple electrons not being able to exist in identical states in an energy level

Question 17

Define emission line spectrum

Answer 17

A series of bright lines at specific frequencies that have been emitted by the gases present. Elements can only release photons if certain energies abs therefore frequencies

Question 18

What’s a Hertzsprung-Russell diagram

Answer 18

A visual representation of the lifecycle of a star. Plots luminosity against temperature

Question 19

Define nebula

Answer 19

Nebula are huge clouds of dust and gas, where stars are born

Question 20

How are nebula are formed

Answer 20

They are formed over millions of years as dust and gas slowly come together due to gravitational attraction to form vast clouds

Question 21

How do stars forms in nebula

Answer 21

Some regions in the nebula cloud are denser than others and the cloud collapses around these denser regions

Question 22

Taking a single dense region in a nebula cloud undergoing gravitational collapse describe what happens in terms of energy when such collapse takes place

Answer 22

Work is done by the inward gravity causing the gravitational potential energy to decrease and the kinetic energy of the gas and dust to increase

Question 23

When a dense in a region undergoes gravitational collapse what happens to the temperature

Answer 23

The temperature increases as it is proportional to the average kinetic energy of the gas and dust which it has been increasing due to the work done by the gravity