Space Flashcards
What is a nebula
Nebula is cloud of gas and dust
What happens to a nebula to make it form a protostar
Gravity pulls dust and gas together making it form a protostar
What happens to a protostar as it gets denser
It’s temperature rises and more particles collide
Eventually, nuclear fission occurs forming helium nuclei out of hydrogen which gives out lots of energy keeping the core hot making it form a star
What happens once a protostar has formed a star
The star enters a long stable period, where the outward pressure from nuclear fusion balances force of gravity pulling it together
It becomes a main sequence star and this period lasts several billions of years
What happens when the stable period of a main sequence star ends
It begins to run out of hydrogen, which causes it to swell to either a red giant or a red supergiant
Fusion of helium then occurs, and heavy elements are created
Why are giants red
Their outer layer cools
What happens to a red giant
It becomes unstable and ejects it’s outer layer of dust and gas, leaving behind a hot, dense, solid core called a white dwarf
What happens to a white dwarf when it cools down
It emits less energy, and eventually hardly emits anything is called a black dwarf
What happens to red supergiants
They start to glow brightly again and undergo more fusion, forming heavy elements
It eventually explodes in a supernova forming elements heavier then iron
What then happens to the exploding supernova
It throws the outer layers of dust and gas into space, leaving either a dense core called a neutron star or if it’s big enough a black hole
What is a black hole
A super dense point in space that not even light can escape from
How do satellites stay in orbit
They travel at a constantly changing velocity
Gravity keeps them in orbit of earth
Move fast enough so that gravity doesn’t pull them towards earth
If the speed of satellite increases what happens to the radius of orbit and why
Radius decreases so gravity is stronger to keep it in orbit
What is red shift and what does it show
Shows universe is expanding as wavelength of light from galaxies far away is shifting towards red end of spectrum
More distant galaxies have a greater red shift, so more distant galaxies are moving away from us faster
What is dark energy
Unknown substance that holds galaxies together
Responsible for accelerated extension of universe
