Chap 11

Question 1

what do galaxies mean

Answer 1

• a set of bodies consisting millions of stars with gas and dust particles

Question 2

3 forms of galaxies:

Answer 2

• spiral
  -elliptical
  -irregular

Question 3

Explain abt the milky way

Answer 3

• a medium large spiral galaxy
• solar system located at the edge of one of the spiral arms
  -consists of approx 200 billion stars

Question 4

Why do all the planets hv their own orbit

Answer 4

• so they dont collide into each other when orbiting

Question 5

List the planets in the solar system in order

Answer 5

• mercury
  -venus
  -earth
  -mars
  -jupiter
  -saturn
  -uranus
  -neptune

Question 6

list life cycle of medium sized star

Answer 6

nebula –> medium sized star –> red giant
–> white dwarf

Question 7

list life cycle of large star

Answer 7

nebula –> large star –> red giant –> supergiant –> supernova –> neutron star

Question 8

list life cycle of super large star

Answer 8

nebula –> large star –> red giant –> supergiant –> supernova –> black hole

Question 9

Explain the birth of stars

Answer 9

-stars formed frm nebulae
-gas n particles in nebula pulled by a strong gravitational force which causes it to form a globe
- causes the globes of gas to shrink n compress until it becomes dense n forms a core
- core shrinks n becomes dense due to increasing strength of the gravitational force
- when temp n pressure in the core is too high, a nuclear reaction will take place
- huge amount of heat energy n light is released
- core will shine n star is formed
- continues to expand

Question 10

what is nebulae

Answer 10

• large clouds consisting of dust particles and gases such as hydrogen and helium

Question 11

explain death of stars

Answer 11

• hydrogen within this layer starts to burn
  -star appears red in color n is called red giant
  -if red giant no massive, white dwarf is formed
• if red giant is big enough, it contracts so quickly that a big explosion called supernova occurs
• supernova is extremely bright
  -if original star is a super large star, black hole is formed

Question 12

characteristics of stars

Answer 12

• colour
  -temperature
  -brightness
  -size
  -distance

Question 13

the really big stars are called

Answer 13

supergiant stars

Question 14

big stars r called

Answer 14

giant stars

Question 15

really small ones r called

Answer 15

dwarf stars

Question 16

brightness of star depends on its

Answer 16

size
distance
surface temperature

Question 17

brightest stars are

Answer 17

sirius and rigel