P8: SATELLITES + THE LIFE CYCLE OF STARS Flashcards
What is a satellite?
an object that orbits a larger object in space
What are the 2 types of satellite?
-natural (occur naturally in space eg: the moon)
-artificial (put into orbit by humans)
Why does velocity of a satellite change when the satellite is orbiting an object?
because direction of satellites movement changes
What is an elliptical orbit?
radius of the orbit changes
How does the size of the radius at which a satellite is orbiting an object affect the speed of the satellite?
as a satellite gets closer to what its orbiting, the speed increases as the force of gravity increases
What is the life cycle of a red giant star (eg: the sun)?
-initially form from a could of dust and gas called a nebula
-the force of gravity pulls the dust and gas together to form a protostar. temp rises as the star gets denser and more particles collide with each other. when temp gets high enough, hydrogen nuclei undergo nuclear fusion to form helium nuclei. this gives out huge amounts of energy which keeps the core of the star hot. a star is born
-the star enters a long stable period where the outward pressure caused by nuclear fusion that tries to expand the star balances the force of gravity pulling everything inwards. In this stable period its called a main sequence star and it typically lasts around 5 bil years
-eventually the hydrogen begins to run out. the star then becomes a red giant (if it is a small star like the sun). it becomes red because the surface cools.
-the star then becomes unstable and ejects its outer layer leaving behind a hot, dense solid core which is called a white dwarf
-as a white dwarf cools down, it emits less and less energy until it eventually becomes a black dwarf
What is the life cycle of a red super giant star?
-initially form from a could of dust and gas called a nebula
-the force of gravity pulls the dust and gas together to form a protostar. temp rises as the star gets denser and more particles collide with each other. when temp gets high enough, hydrogen nuclei undergo nuclear fusion to form helium nuclei. this gives out huge amounts of energy which keeps the core of the star hot. a star is born
-the star enters a long stable period where the outward pressure caused by nuclear fusion that tries to expand the star balances the force of gravity pulling everything inwards. In this stable period its called a main sequence star and it typically lasts around 5 bil years
-eventually the hydrogen begins to run out. the star then becomes a red super giant (if it is a big star). it becomes red because the surface cools. Fusion of helium (and other elements) occurs and heavier elements up to iron are created in the core of the star.
-eventually the star will explode in a supernova, ejecting the elements that had been formed in the star’s core and distributing them across the universe
-the supernova throws outer layers of dust and gas into space leaving a very dense core called a neutron star
-if the star is big enough it will become a black hole
