Name the force that draws together dust and gas in a nebula
Gravity
Name the stage in a star's lifecyle that comes before protostar
Nebula
Name the force that tries to collapse a main sequence star
Gravity
What provides the outward pressure in a main sequence star?
Fusion reactions (of hydrogen to helium)
Name the stage after the main sequence for a massive star
Red super giant
Name the stage after a red super giant
Supernova
Name the stage after red giant
White dwarf
Name the final stage in the lifecycle of the Sun
black dwarf
What do the most massive stars eventually become?
Black hole
Name the heaviest elements that can be produced in fusion reactions
Iron
How are elements heavier than iron produced?
In a supernova explosion
Describe the process of nuclear fusion
Very high temperature and pressure force together two small nuclei to produce a single larger nucleus
HIGHER
Why does the force of gravity not cause an orbiting satellite to change speed?
Gravity acts towards the centre of the circle, perpendicular to the direction of motion. There is no component of gravity acting in the direction of motion so there is no change of speed.
Name the almost circular path taken by planets as they orbit stars
Ellipse / elliptical
HIGHER
How does the speed of a planet change as it gets closer to its star?
Increases (as gravity increases)
Light from distant galaxies appears to have a longer than expected wavelength. What does this demonstrate?
That they are moving from us.
Name the effect whereby light from distant galaxies appears to have a longer than expected wavelength.
Red shift
Compare the recession speed of near and distant galaxies.
Distant galaxies are moving away faster than nearby galaxies
What does the amount of red-shift show?
How fast a galaxy is moving away
If a galaxy showed blue-shift, what would this mean?
That the galaxy is moving towards us
Name the most commonly accepted model explaining the creation of the Universe
Big Bang
What provides the best evidence for the Big Bang model?
Red-shift
Explain why the light from an object moving away appears to have a greater wavelength than it should
As the object is moving away, the distance between wavefronts appears to increase
increases
Name a key feature of the Universe that scientists know little about
Dark energy
Dark mass/matter
Name a piece of evidence that seems to contradict the Big Bang theory
Observations of supernovae seem to suggest that distant galaxies are receding at an increasing rate
State how distance from object affects the strength of gravity