P16 - Space (PAPER 2) Flashcards
What is the solar system formed from
gas and dust clouds that become very concentrated due to gravitational attraction
What is a protostar
a concentration of gas and dust that becomes hot enough to cause nuclear fusion
How is energy released from a star
hydrogen nuclei fuse together helium nuclei
Why is the Sun stable
because of the gravitational forces acting inwards balance the forces of nuclear fusion energy in the core acting outwards
When do stars become unstable
when they have no more hydrogen nuclei that they can fuse together
What are the stages of life of a star of similar size to the sun
protostar -> main-sequence star -> red giant -> white dwarf -> black dwarf
What are the stages of life of a star much larger than the sun
protostar -> main-sequence star -> red supergiant -> supernova -> neutron star / black hole
What is a supernova
the explosion of a red supergiant after it collapses
Where does the force of gravity on an orbiting body in circular orbit attract to
the centre of the circle
What happens to
- magnitude of velocity
- direction of velocity
as a body in circular orbit moves around its orbit
the magnitude stays the same,
direction always changes and is always at right angles to the force
Where does a body in circular orbit experience an acceleration
towards the centre of the circle
Why is the red-shift of a distant galaxy the shift to longer wavelengths of the light from the galaxy
because it is moving away from you
What is the correlation between the speed of a distant galaxy and its red-shift
the faster the galaxy is moving, the greater the red-shift
What is the correlation between how far a galaxy is from Earth and its red shift
The further away the galaxy, the larger the red-shift
Why are all distant galaxies moving away from Earth
because the universe is expanding
