P8 Flashcards
Explain why the star is stable while it is in the main sequence stage of its life cycle.
Inward force of gravity and outward force due to fusion are balanced
Describe what will happen to the star between the main sequence stage and the end of the star’s life cycle for star same size as the sun
Star expands to form a red giant
Star collapses forming a white dwarf
Star cools forming black dwarf
Explain why the velocity of the satellite changes as it orbits the Earth.
- (force of) gravity causes the satellite to accelerate (towards the Earth)
- the acceleration causes a change in direction
- velocity changes because direction changes
How does red shift support the idea of the Big Bang theory?
- the furthest galaxies show the biggest red shift
- (meaning that) the furthest galaxies are moving fastest
- (so the) Universe is expanding
- (extrapolating backwards this suggests that) the Universe started from an initial point
What is another factor supporting the idea of the Big Bang theory?
cosmic microwave background radiation
Describe the ‘big bang’ theory.
universe comes from a single hot, dense point and explosion caused it to expand
Describe how stars release energy
- nuclei / atoms of light elements (like hydrogen) fuse
- each (fusion) reaction releases energy / heat / light
Define a black hole
(matter / mass) with such a high density / strong gravitational (field) electromagnetic radiation / light is pulled in
Difference between protostar and main sequence star
a protostar does not emit radiation /energy
as (nuclear) fusion reactions have not started
