Topic 8 Flashcards
Example of a natural satellite
Moon
Example of artificial satellite
Satellite from Elon
What is the initial form of a star called
what is it ?
A nebula
A cloud of dust as gas
What is the second stage of star cycle
How is it formed
What is it
Protostar
Formed when gravity pulls a nebula together
Gas and dust gradually getting denser
What is third stage of star cycle
How it formed
What is it
Main sequence star
When temp in a protostar gets high enough for helium nuclei to do fusion - gives out energy forms star
A stable period where the pressure caused by fusion and gravity balance (this is what our sun is in)
What is stage 4 if star cycle
How is it formed
What is it
Red giant - same size as sun / super red giant - bigger than sun
When hydrogen of main sequence star runs out
It is red as surface cools
Fusion of helium and other elements happens
Heavier elements up to iron form core
What is stage post red giant of star cycle
How is it formed
What is it
White dwarf
When red giant becomes unstable and ejects its outer layer of dust and gas
The hot dense solid core of a red giant
What is stage post white dwarf of star cycle
How is it formed
What is it
Black dwarf
As white dwarf cools down and emits less energy
A white dwarf that no longer emits a lot of energy
What is stage post red super giant of star cycle
How is it formed
What is it
Supernova
When a red super giant undergoes a lot of fusion and expands and contacts several times - this then explodes in a supernova forming elements heavier than Iron
Explody red super giant - its elements are ejected into universe to form new planets and stars
What is stage post supernova of star cycle
How is it formed
What is it
Neutron star / black hole
When the outer layers of gas from a supernova are thrown into space leaving a very dense core behind - neutron star
If it is big enough it will become a black hole - a super dense point not even light escapes from
How do orbits work
Gravity changes the direction of already moving object
What does the size of an orbit depend on
An objects speed - the stronger the force the more speed needed to stay in orbit
Faster moving objects will have a smaller orbit as more force is needed to counter the stronger grav pull
What is red shift
Wavelengths from other galaxies shifting towards the red end of the spectrum
What does red shift suggest
Distant galaxies are moving away faster than nearer ones - all galaxies are moving away due to the space between galaxies expanding
What is different about further galaxies red shifts
They are greater than nearer ones
