| Describe the structure of the universe | Solar system of planets, dwarf planets and moons in the Milky Way galaxy orbiting the sun |
| What is the life cycle of a star? | Nebula [cloud of dust and gas]
Protostar [Helium nuclei formed from particles colliding creating a high temperature]
Main Sequence Star [Star enters a long stable period generally several billions of years]
Then either:
Red Giant [Hydrogen runs out and star swells]
White dwarf [Becomes unstable and ejects outer layer of dust and gas leaving core]
Black Dwarf [White dwarf cools down, emits less energy]
Or:
Red Super Giant [Hydrogen runs out and star swells to bigger than Sun]
Supernova [Star undergoes more fusion and expands and contracts until it explodes]
Neutron Star [Exploding supernova leaves a very dense core] or
Black Hole [Exploding supernova leaves a super dense point in space] |
| How do fusion processes lead to the formation of new elements? | Two or more atomic nuclei collide at nearly the speed of light to form a new nucleus |
| What are the differences between planets? | Inner planets are rockier and smaller, whilst outer planets are filled with more gas and are larger
Inner planets are more dense and all have different atmospheres whilst outer planets are less dense and have similar atmospheres made of hydrogen and helium |
| What is the difference in planet moons? | Outer planets have more |
| Why in orbits does velocity change but not speed? | There is a constant change of direction in a circular motion so acceleration is constantly happening- therefore velocity constantly changes but speed does not |
| For a stable orbit, what must change if the speed changes? | The radius of the orbit [if increasing speed the radius becomes smaller] |
| What is red-shift? | Where wavelengths are shifted to the red end of the spectrum |
| What does red-shift suggest? | That distant galaxies are moving away from us |
| How does red-shift provide evidence of the Big Bang Theory? | Shows galaxies are moving away from each other so suggests that the universe began with a 'big bang' that began the dispersion of galaxies |
| What is the Big Bang Theory? | That an explosion provided the force that pushes galaxies away from each other at speed |
| What do moving galaxies show? | That the universe is expanding because they keep getting further and further away without limit |
| What observations have scientists made to theorise 'The Big Bang'? | Supernovae in 1998 to the present day show the increasing speed of the receding galaxies |
