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state what is in the solar system
the Sun
eight planets
and dwarf planets
that orbit the Sun
and moons
that orbit planets
state what the Sun is
a star
state what moons in the solar system are
natural satellites
state what galaxy the solar system is part of
milky way galaxy
state what formed the Sun
a nebula
pulled together
by gravitational attraction
state nebula definition
cloud of dust and gas
state what causes nuclear fusion to occur
when two light nuclei
collide at high speed
and join to create
a larger, heavier nucleus
explain how the formation of a star causes fusion reactions
a star is formed when
it is hot enough
for hydrogen nuclei to undergo nuclear fusion
to make a helium nucleus
explain how fusion reactions of stars leads to an equilibrium between the collapse of a star and the expansion of a star
gravitational attraction tends to collapse stars
radiation pressure from fusion reactions tend to expand stars
forces caused by gravitational attraction and fusion energy are balanced
state what cycle a star goes through
life cycle
state what a life cycle determines
the size of the star
state the life cycle of a star the same size as the Sun
nebula
protostar
main sequence star
red giant
white dwarf
black dwarf
state the life cycle of a star much bigger than the Sun
nebula
protostar
main sequence star
red super giant
supernova
neutron star/black hole
state what fusion processes in stars produces
naturally occurring elements
state where elements heavier than iron are produced
supernovas
state what the explosion of a supernova does
distributes elements throughout the universe
explain how fusion processes lead to the formation of new elements
majority of a star’s life, hydrogen nuclei fuse together to form helium nuclei
as a star runs out of hydrogen, other fusion reactions take place
forming the nuclei of other elements
forming elements lighter than iron in this way
the explosion of supernovas forms elements heavier than iron
as the explosion releases large amounts of energy and neutrons
all elements produced by fusion reactions in stars
gets thrown out and combine with with the neutrons
to form heavier elements
state what allows planets and satellites to maintain their circular orbits
gravitational force
state the similarities between planets, moons and artificial satellites
all orbit larger celestial bodies
due to gravitational forces
state the differences between planets, moons and artificial satellites
artificial satellites are man-made
planets and moons are natural
explain how in circular orbits, the force of gravity can lead to changing velocity but unchanged speed
velocity is a vector quantity
objects in orbit is accelerating
although its speed is constant
because its direction is constantly changing
state what is needed for stable orbit
radius of the orbit must change
is speed changes
state red shift definition
when wavelength of light
and the speed galaxies move at
increases in distant galaxies
state what the red shift provides evidence for
provides evidence that space is expanding
and supports the Big Bang theory
state what the big bang theory suggests
universe began from
a very small region
that was extremely hot
and dense
describe observations of supernovae from 1988 suggest
distant galaxies are receding even faster
explain how red shift provides evidence for the big bang model
light spectrums from supernovae show that light from distant galaxies is redshifted
which suggests that the universe is expanding
as the Big Bang, a series of explosions
causes densely-packed matter to move out in all directions
and move further from the source of the explosion
before the Big Bang, galaxies were so close together that the entire universe was a single point
if the galaxies were originally grouped together and were then exploded, we would observe a similar red-shift effect
state the doppler effect definition
a moving object will cause the wavelength of waves to change
the wavelength of the waves in front of the object decreases
and the frequency increases
the wavelength of the waves behind the object increases
and the frequency decreases
state blueshift definition
when an object moves towards an observer
the wavelength of light decreases
as the light moves towards the blue end of the visible light spectrum
explain how the change in each galaxy’s speed with distance is evidence of an expanding universe
light coming to the milky way galaxy from distant galaxies is redshifted
as the visible light spectrum is shifted towards the red end
indicating that galaxies are moving away from us
if galaxies are moving away from us, then the universe is expanding
the greater the distance of the galaxy, the greater the redshift
meaning that the further away the galaxy is, the faster it is moving away from us
explain why there is still not much known about the universe
evidence from the rotation and motion of galaxies suggests that
there is much more matter in the universe than we are able to account for
this unseen matter is dark matter and its nature isn’t currently known
measurements of the expansion of the universe using supernovae suggest that the universe is expanding at a faster rate
it’s suggested that this is caused by dark energy pushing everything in the universe apart
if gravity was present everywhere in the universe, it would be expected that one day everything in the universe would get closer
which is the opposite of what we see
it’s suggested that dark energy may be counteracting gravitational forces in the universe
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Flashcard (135)