space - the solar system

Question 1

what are the main parts of the solar system?

Answer 1

centre of solar system is the sun (star), eight main planets orbiting the sun; mercury, venus, earth, mars, (first 4 are relatively small rocky planets) jupiter, saturn, uranus + neptune (these 4 are much larger). beyond orbit of Neptune, there is a number of dwarf planets (extremely small) such as Pluto. also other objects such as moons, asteroids, and comets

Question 2

how is the solar system part of the milky way galaxy?

Answer 2

solar system is just a tiny part of the milkway galaxy. a galaxy is a massive group of stars and the milkway contains hundreds of billions of stars and in universe hundreds of of billions of galaxies

Question 3

how are stars such as the sun formed

Answer 3

• stars form from clouds of dust and gas. this is called a nebula and the gas in a nebula is mainly hydrogen
• first, gravity causes the cloud of dust and gas to collapse. as dust particles move faster, the temperature rises to millions of degrees celsius. this collapsing cloud of hot air is called a protostar
• if temp of protostar gets high enough then hydrogen nuclei join together to form helium. process called nuclear fusion. protostar has now turned into a star
• nuclear fusion now releasing huge amounts of energy

Question 4

what are moons?

Answer 4

natural satellites which orbit planets. most planets in solar system have at least one moon and some planets have a large number of moons

Question 5

stars

Answer 5

• there are 2 opposing forces acting within a star. the force of gravity acts inwards and tends to make the star collapse. the energy from nuclear fusion creates a force acting outwards, tends to make star expand.
• force of gravity acting inwards is balanced by force due to fusion energy acting outwards. because these a balanced, the star is in equilibrium