space physics Flashcards
what is a satelite
anything that orbits a planet
what are the 2 types of satelites
natural-arent man made
artificial-are man made
what is an example of a natural satelite
moon
what is an example of artficial satelites
communication
orbiting telescopes
eg international space station
how many planets are they and what do they orbit
-8 planets
-orbit central star(the sun)
what are the 8 planets
mercury
mars
venus
jupiter
saturn
uranus
earth
neptune
how do all planets orbit the sun
in an elliptical orbit
what are asteroids
objects made of mostly rock and metal in the solar system
where asteroids mainly found
in the asteroid belt between mars and jupiter
what are comets
objects made of ice and dust that orbit elliptically
what are galaxies
collections of billions of stars(with their own solar systems)
what holds the stars together
force of gravity
what makes up the universe
trillions of scattered galaxies and empty space
what are star systems
central star orbitted by planets except ours which is called solar system
what galaxy is our system in
Milky way
what is a nebula
a big cloud of dust and gas
how is a protostar formed
a nebulas dust and gas is pulled together by gravity to form it
what 2 steps happens when as a protostar grows
-more particles collide and join protostar making it grow
-gravity gets stronger
step 3/4 of protostar growth
more gas and dust is attracted
and it is squeezed to become more dense
how does the temp of a protostar increase
as it densens particles collide more often raising temp/pressure
step 5 and 6 of protostar growth
hydrogen nuclei fuse to form helium nuclei by nuclear fusion releasing lots of energy making core hot
what happens after step 5/6 of protostar growth
it is now called a main sequence star or an actual star
why do main sequence stars last for billions of years
the inward pressure of gravity=outward of nuclear fusion resulting in a long stable period
what is an example of a main sequence star
sun
1st step of what happens when main sequence star runs out of hydrogen(fuel)
star can no longer do fission
and gravity contracts star into small ball until its so hot/dense
2nd step of what happens when main sequence star runs out of hydrogen(fuel)
nuclear fusion can restart and star expands again and forms heavier elements up to iron(not just helium)
what do small/medium main seq stars form
red giants
what do really big main seq stars form
red super giants
how is a white dwarf formed step 1
-red giant becomes unstable and expels outer layers
how is a white dwarf formed step 2
becomes small hot dense solid core incapable of nuclear fusion called white dwarf
how is a black dwarf formed
white dwarf cools and darkens as it emits all its energy.no longer has enough to emit light forming
black dwarf
how do red super giants undergo supernovas
they undergo more fusion and expand and contract over several cycles
they then explode
what does a supernova do
forms and ejects elements heavier than iron
what 2 things can happen to red super giants after undergoing supernova
very big-forms neutron star with very dense core
absolutely massive-collapses into black hole
why do we call them black holes
so dense the gravity pulls in any light nearby so no light is ever emitted
what is an orbit
the curved path of one celestial object/spacecraft around another celestial object
give 2 examples of orbits
moon orbiting earth
earth orbiting sun
every time the moon changes direction as it orbits what can we say its doing
accelerating
why is there a force acting on the moon in its orbit of the earth
earth is massive and has a strong gravitational(attractive force) pull
they are also quite close
why doesnt the moon get pulled towards the earth
has a lot of momentum in direction it travels in so gravitational force can only change its direction slightly
the earth always applies gravitational force.what does this mean happens to the moon
moon always orbits earth
is the speed of the moon always the same
yes
because the moon is always changing direction what does this mean
its velocity is constantly changing so it is also accelerating as it changes direction
what 2 things result in a steady orbit
the instantaneous velocity of orbiting object
gravitational pull of object being orbited
if the moon got closer to the earth what would increase
the earths gravitational force as the distance is smaller
what would happen if moons orbit became closer to earth
likely get sucked in towards the earth
how would the moon maintain a stable orbit and not be pulled in towards earth if it got closer
travel much faster to increase its instantaneous velocity
the smaller an objects orbit
the faster it must travel to maintain a stable orbit
what is the central idea about space observation
from earth every direction we look into space galaxies seem to move further away
universe expanding
why do galaxies appear to be moving away from us
as the space between us and the galaxies is expanding
the further away a galaxy is
the quicker it appears to be moving away
limitations/pro of baloon model to visualise galaxy expansion
balloon would burst when it expanded too much whereas universe isnt likely to
galaxies should be inside balloon instead of on surface
dots get further as balloon expands representing space and galaxies moving apart
what do models do
help us understand difficult concepts
what is the big bang theory
all matter in the universe took up tiny space that was dense and hot.
it then exploded and space began to expand as it is to this day
what does the sun emit
different wavelengths of light to earth
roygbiv on the absorption spectra
what does the suns atmosphere contain
different chemicals that absorb certain wavelengths of light
what does the chemicals in the sun absorbing wavelengths mean
certain wavelengths are missing by the time they reach earth
how do we show the missing wavelengths on the absorption spectra
dark lines
with light from different galaxies how is the absorption spectra different
the black lines are in the same pattern but all shifted to the red end(left)
what is the red shift
wavelengths of light from distant galaxies are longer(stretched) than they should be and are shifted toward the red end
what does the red shift suggest
the source of light is moving away from us
how is the red shift of more distant galaxies different to closer
more distant have greater red shifts so are moving away faster
explain the balloon pompom model
as you blow into a pompom covered balloon the space between the pompoms increase
what is Cosmic microwave background radiation (CMBR)
electromagnetic radiation that is observed in all directions.
why is nothing certain in space and the universe
still alot unknown and observations being made
eg dark matter/energy made of unknown substances
the faster an object moves away from us
the larger the red shift
how do we know universe is expanding
all galaxies are moving away from us and each other which red shift shows us
why are theorys believed
Its predictions are supported by observations
