P8 - Space Physics Flashcards
Describe the main parts of the solar system
A star - the sun
8 main planets -
(Mercury, Venus, Earth & Mars): Relatively small, rocky planets.
(Jupiter, Saturn, Uranus, Neptune): Much larger
Moons are:
Natural satellites which orbit planets
Explain how stars form
Gravity causes the cloud of dust & gas (Nebula) to collapse.
As dust particles move faster, the temp rises to millions of degrees Celsius (Protostar).
If temp of protostar gets high enough, hydrogen nuclei join together to form helium. (Nuclear fusion)
The protostar has turned into a star
Nuclear fusion is now releasing huge amounts of energy.
Explain the 2 opposing forces acting within a star
Force of gravity acts inwards & tends to make the star collapse.
Energy of nuclear fusion creates a force acting outwards & tends to make the star expand.
The forces are balanced - the star is in equilibrium
Elements heavier than iron are produced in a…
Supernova
Fusion processes in stars produce…
All of the naturally occurring elements.
Explain how the force of gravity can lead to changing velocity but unchanged speed
The speed remains constant but the direction constantly changes due to gravity, meaning the velocity constantly changes.
Explain how for a stable orbit, the radius must change if the speed changes.
If the speed of the satellite increases, the radius of its orbit decreases.
At a higher speed, the satellite needs a greater force of gravity to prevent it flying off into space.
Describe red-shift
Observed light from distant galaxies is different to light from the sun and an increase in wavelength is observed.
The lines are shifted towards the red end of the spectrum.
Explain how red-shift provides evidence for the Big Bang theory
The further away a galaxy is, the more red-shifted its light is.
The further the galaxy, the faster it is moving.
