Topic 8 -Space Physics Flashcards
first 3 steps in the creation of a star
- Dust and Gas (nebula) pulled together by gravity to form a protostar
2.As the protostar grows in size and attracts more particles from the surrounding nebula
The temperature increases , Nuclear fusion could initiate , It becomes more dense
- Then nuclear fusion starts to take place(using hydrogen as fuel) in a protostar , forming a main sequence star , leading to an equilibrium between the gravitational collapse of a star and the expansion of a star due to fusion energy.
Example of satellites
satellites orbit a planet and they can be artificial or natural for example the moon or the space station
steps at the end of a main sequence stars life (for a red giant)
It turns into a white dwarf and then a black dwarf
steps at the end of a main sequence stars life (for a red super giant)
It explodes into a supernova forming elements even heavier than iron. These elements are ejected all across the universe.
After this it can either , condense into a neutron star or collapse into a black hole
how are elements in space formed
Fusion processes in stars produce all of the naturally occurring elements - helium atoms fuse and form helium , helium can fuse to form other elements. Elements heavier than iron are produced in a supernova.
What maintains an orbit in space
Gravity provides the force that allows planets and satellites (both natural and artificial) to maintain their circular orbits.
How does gravity cause an increase in velocity during orbits
Newton first law - An object travelling at a certain velocity will continue to travel at that velocity unless acted upon by a resultant force.
Gravity has a strong pull to the earth so the moon must change its direction constantly to stay within a circular orbit
speed stays same but direction changes = velocity changes
if speed of artificial satelite increases , radius of orbit decreases
What can you say about the relationship between the size of an objects orbit and its speed
The smaller an objects orbit the greater speed it has to travel at - this is because closer theres more gravitational forces and the speed must increase to resist these forces
All to maintain a stable orbit
Explain what red- Shift is
Red shift is the longer wavelength of light on the spectrum - this is because light is emitted from galaxies and the further away galaxies are , the more stretched the light is - this wavelength of radiation is red shift
the more
How is the big bang proven by red shift
The observed red-shift provides evidence that space itself (the universe) is expanding- this means the universes themselves arent moving away from eachother , the space between it is expanding - like the balloon model ; and supports the Big Bang theory. The Big Bang theory suggests that the universe began from a very small region that was extremely hot and dense.
