Cosmology

Question 1

Nebulae

Answer 1

Clouds of dust, hydrogen, ice and helium.
Birthplace of new stars
Found in empty space between stars

Question 2

Stars

Answer 2

Celestial bodies that create their own light and heat from nuclear fusion within their core. They are collected together in galaxies.

Question 3

Solar system

Answer 3

refers to a star and all the objects that travel in orbit around it

Question 4

All objects…

Answer 4

exert a force of gravity on all other objects in the universe

Question 5

Galaxy

Answer 5

giant collection of gas, dust and stars held together by gravitational attraction
grouped in clusters

Question 6

planets

Answer 6

as a natural object in space that is massive enough for gravity to make it approximately spherical
orbit stars
they do not create their own light

Question 7

Black hole

Answer 7

region in space where gravity pulls so much that even light cant get out. The gravity is so strong because the matter in a black hole is extremely dense.
Created either when a massive star collapses or at the beginning of the Universe

Question 8

1 astronomical unit (au)

Answer 8

approx 150 million km

Question 9

1 light year (ly)

Answer 9

9.5 x 10(12) km

Question 10

nuclear fusion

Answer 10

the source of energy in the stars
fuel of hydrogen cannot last forever

Question 11

Structure and size of star depends on balance between

Answer 11

inward force of gravity pulling towards the stars centre
outward force of radiation pressure, the force caused by the heat from nuclear fusion

Question 12

life cycle of a star (Sun)

Answer 12

nebula, protostar, main sequence star like our Sun, planetary nebula, white dwarf, black dwarf

Question 13

life cycle of a star (bigger than Sun)

Answer 13

nebula, protostar, supergiant star, red giant, supernova, neutron star or black hole

Question 14

star size

Answer 14

determined by the balance between the inward force of gravity which pulls matter towards he centre of the star, and the outward force of radiation pressure that results from the pressure caused by the heat radiated from nuclear fusion within the star

Question 15

Neutron star

Answer 15

a dense celestial object that consists primarily of closely packed neutrons
resulted from the collapse of a supergiant stellar body

Question 16

red giant

Answer 16

dying star in the final stages of stellar evolution
hydrogen in the core runs out, star burns helium to produce carbon, atmosphere of star expands up to 100 times its original diameter

Question 17

white dwarf

Answer 17

stellar core remnant composed mostly out of electron degenerate matter
dense
no more nuclear fusion occurs and remaining core collapses due to gravity

Question 18

black dwarf

Answer 18

stellar remnant, white dwarf that has cooled sufficiently to no longer emit significant heat or light

Question 19

planetary nebula

Answer 19

regio fo cosmic gas and dust formed from the cast off outer layers of a dying star

Question 20

protostar

Answer 20

a cloud of interstellar gas and dust that gradually collapses, forming a hot dense core, and evolves into a star once nuclear fusion can occur in the core

Question 21

apparent magnitude

Answer 21

a measure of how bright a star appears to an observer on Earth

Question 22

2 factors that determine a stars apparent magnitude

Answer 22

the amount of light it emits and the distance between the star and Earth

Question 23

absolute magnitude

Answer 23

brightness of the star if it was 10 parsecs from Earth, where 1 parsec= 3.26 light years

Question 24

2 factors that determine a star’s colour

Answer 24

surface temperature and which elements it contains
the age of the star and the ratio of hydrogen to helium changes the colour