SPACE Flashcards
(28 cards)
satelite
anything that orbits a planet
elliptical orbit
the path planets take isnt a perfect circle
asteroids
mainly found in the asteroid belt
made mostly of rock & metal
comets
made of ice & dust
much more elliptical orbits
travel outskirts of solar system
galaxy
collections of billions of stars
+ have their own solar systems
WERE IN MILKY WAY
what was our sun formed from
a cloud of dust and gas (nebula) pulled together by gravitational attraction
solar system
consist of a central star that planets orbit
life cycle of star the same size as the sun
NEBULA - PROTOSTAR - MAIN SEQUENCE STAR - RED GIANT - WHITE DWARF - BLACK DWARF
life cycle for a star much bigger than the sun
NEBULA - PROTOSTAR - MAIN SEQUENCE STAR - RED SUPERGIANT - SUPERNOVA - NEUTRON STAR / BLACK HOLE
how is a protostar formed
gravity pulls dust & gas together to form it
then more and more particles collide & join the protostar - so gets bigger , w/ stronger force of gravity , so attracts more dust & gas
(also gravity squeezes protostar - more dense)
particels collide more often - raises the temp = hydrogen nuclei start to fuse together - form helium nuclei - gives out huge amounts of energy - keeps core hot
how does a main sequence star form
how is a main sequence star fomed
nuclear fusion of hydrogen, making helium nuclei in a protostar, which gives out huge amounts of energy
outward pressure (nuclear fusion) & inward pressure (gravity) are BALANCED - long stable period (where our sun is)
what happens towards the end of a main sequence stars life
run out of hydrogen
inward pressure (gravity) takes over & contracts star into small ball unitl its so hot & dense that nuclear fusion can start up again , causing it to expand
then it forms heavier elements (instead of helium)
options after main sequence star
red giant
red supergiant
how is a white dwarf formed
red giant becomes unstable & expels its outer layers of dust/gas
leaves behind a hot dense solid core (=WHITE DWARF) , that doesnt do any nuclear fusion
how is a black dwarf formed
white dwarf gets cooler & darker
no longer has enough energy to emit light
whtat comes after a red supergiant
SUPERNOVA
how does a supernova form
red supergiant goes through several cycles of expansion & contraction and eventually explodes
what do supernovas do
form elements heavier than iron which get ejected across the universe
options after supernova
if very big:
NEUTRON STAR (dense core)
if absolutely massive:
BLACK HOLE (collapses in on itself )
black hole
gravity is able to pull in any light that passes nearby
what force allows planets & satelites to maintain their circular orbits
gravity
what can gravity change in circular orbits
CHANGING VELOCITY
BUT NOT SPEED
stable orbit
if the speed changes, the radius must change
