P16 Space Flashcards
describe the formation of a star
- clouds of dust and gas are pulled together by gravitational forces of attraction,
- particles become concentrated and sped up: a PROTOSTAR,
- protostar becomes denser, particles collide more frequently so temp increases,
- hydrogen nuclei fuse into helium nuclei, forming a STAR,
- objects too small to form a star may become planets that orbit a protostar.
describe the main sequence of a star
- hydrogen nuclei in core perform nuclear fusion to form helium nuclei,
- releasing energy that keeps it hot and flows in all directions from the core as gamma radiation,
- which sustains the star’s energy output for millions of years.
why is a main sequence star stable?
the outward force of nuclear fusion in the core is balanced out by the inward force of gravity acting down onto the star, keeping it in equilibrium.
heaviest known natural element
and what does it prove
uranium
proves that the Earth formed from remnants of a supernova
what happens to a star the same size as or smaller than the Sun at the end of its main sequence
what happens to a star larger than the Sun at the end of its main sequence
what becomes of a smaller star after a supernova
what becomes of a larger star after a supernova
describe the direction of motion of any planet
perpendicular to the direction of the force of gravity on it
how does the distance an orbiting body is from what it orbits affect its speed
the further an orbiter is from its planet
the weaker is the force of gravity on it
meaning less speed is needed to keep it in orbit
red shift
planets are moving Away, wavelengths Increase
RAI
blue shift
planets move Towards, wavelengths Decrease
BTD
why are distant galaxies moving away from us at a faster rate than nearer ones
because the universe is expanding
what does the Big Bang Theory suggest?
the universe started from a small, hot and dense region
what is CMBR
cosmic microwave background radiation
radiation coming from all directions in space
