4.8.1.1 Our Solar System

Question 1

What is within our solar system?

Answer 1

• there is one star - the Sun
• the 8 planets and the dwarf planets which orbit around the sun
  
  • Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
• natural satellites, the moons that orbit planets, are also part of the solar system
• asteroids and comets

Question 2

What is our solar system part of?

Answer 2

our solar system is a small part of the Milky Way Galaxy

Question 3

What was the sun formed from?

Answer 3

the Sun was formed from a cloud of dust and gas drawn together by gravitational attraction

Question 4

How does a star form e.g. the sun?

Answer 4

• the sun was formed from a cloud of dust and gas (nebula - the main gas in a nebula is hydrogen) drawn together by gravity which caused fusion reactions
• gravity causes the cloud of dust and gas to collapse
• as the dust particles moved faster the temp rises to millions of degrees C
• called a protostar

Question 5

What is a protostar?

Answer 5

scientists call the collapsing cloud of hot gas and dust a protostar

Question 6

What happens if the temperature of a protostar gets high enough?

Answer 6

• if temperature of protostar gets high enough then the hydrogen nuclei fuse together to form helium (nuclear fusion)
• protostar turned into a main sequence star and nuclear fusion releasing a huge amount of energy
• the fusion reactions lead to an equilibrium between forces of the gravitational collapse of a star and the forces causing the expansion of a star due to fusion energy

Question 7

What are the 2 forces acting on a star and how do they interact?

Answer 7

• force of gravity acts inwards and tens to make the star collapse
• E from nuclear fusion creates force acting outwards and tends to make the star expand
• force of gravity acting inwards is balanced by the force due to fusion energy acting outwards - star in equilibrium as the forces are balanced