Physics Space Flashcards
The sun is the only star in the
solar system
There are how many planets in our solar system
8
What type of celestial body is a moon?
natural satellite
Formation of the sun steps
- Cloud of gas and dust (a nebula) collapsed due to gravity
- This formed a protostar which continued to accumulate more mass
- The temperature and pressure became high enough for nuclear fusion to start
- The star then went into a stable period called a main sequence star
In the Sun, what process creates a force outwards, balancing the inward force of gravity?
Nuclear fusion
The Sun is
currently ————–
and is powered by nuclear ———–
and is a ———– ————– star
stable
fusion
main sequence
weight with units equations =
weight in newtons
mass (kg) * gravitational field strength N/kg
comets and asteroids are balls of
which orbit the
ice and rock which also orbit the sun
If the speed of the object in orbit changes then the
the radius of the orbit also changes.
If the radius of the orbit increases then the
This explains why planets closer to the sun travel at a faster speed.
the speed decreases as the gravitational attraction is smaller.
What happens when the radius of an object in orbit decreases?
speed increases
What happens when the radius of an object in orbit decreases?
it speeds up
In a main sequence star, ——————are fused together to form ——.
This releases energy as ——-and ——.
hydrogen nuclei
heluim
heat
light
Red giant formation
Eventually all the hydrogen fuel runs out.
The star then cools and expands, becoming a red giant.
The star then starts to fuse together helium nuclei to release energy.
It is formed when he outward force of the energy is larger than the inward force of gravity so the star expands.
White dwarf process
As the heluim fuel runs out in a small to meduim star like the sun then the, the outward forces reduce in size and the star collapses inwards ejecting its outer layer of gas and dust.
This causes is temperatures to increase. A white dwarf is formed which is the hot core of the star.
Black dwarf very short summary
when the stars completely cools it becomes a black dwarf.
A black dwarf doesn’t emit any light or heat
How does a star become a super red giant quick summary
Nuclear fusion changes more and more of the star’s mass into energy. The star expands into a red super giant
Supernova quick summary (about how its created) what does it produce?
the largest stars explode into supernovas. A supernova produces elements heavy than iron and scatters them throughout the universe.
Black holes and neutrons stars are formed
by a supernova
Life Cycle of a large star
- Gravitational attration pulls dust and gas together to form a protostar. As the density increases the temp rises. When the temp gets high enough nuclear fusion happens and a huge amount of energy is emitted
- Main sequence star formed powered by nuclear fusion the star enters a long stbale priod where outward pressure ccaused by the nuclear fusion balances the forces of gravity pulling everything inwards. So the forces are balanced so it doesn’t collapse or explode. This typically lasts several billion years.
- The star expands becoming a super red giant
- The star explodes into a supernova
- The supernova leaves behind either a black hole or a neutron star
All stars fuse ——– nuclei into ——- in nuclear ———
hydrogen
helium
fusion
Larger stars fuse —— nuclei into ——- and other ———
heluim
lithium
of light metals
Describe red shift and explain how it supports the big bang theory as an explanation for how the universe began
(6 marker)
Red shift is when the wavelengths of observed light from a source are longer than that of the light emitted from the source. This occurs when the source of the light emitted by the source is moving away from the observer.
The light from the most distant galaxies is observed to be red-shifted. The light from galaxies that are further away from us is more redshifted than the light from nearer galaxies. This inidcates that all of these glaxies are moving away fromand each other. This suggests that the universe is expanding. The Big Bang theory is the theory that the universe began as a small region of space that was very hot and dense which exploded and his been expanding ever since. Therefore the observations of red-shift support the idea of the origin of the universe suggested by the BIG BANG THEORY
Evidence for an expanding universe
Light from distant galaxies in space is red-shifted. The further a galaxy is from earth, the Greater the red shift. This means that the further away a galaxy is, the faster it is moving away from us.
define dark matter
an unknown substance that holds galaxies together but doesn’t emit electromagnetic light radiation
define dark energy
the thing that causes the universe to quickly expand
Neumonic:
My Mercury
Very Venus
Easy Earth
Method Mars
Just Jupiter
Speeds Saturn
Up Uranus
Naming Neptune
The doppler effect causes the wavelength of light from galaxies moving away from us
to increase in length . This moves the position of absorption lines towards the red end of the spectrum, so it is called red-shift.
LEO Sattelite
LOwer
earth
orbit
Used for communication (orbit is about 90 minutes, gives detailed images of Earth)
Black holes are
a super dense point in space that not even ligh can escape from
neutron star is a
very dense core
If an object is continually moving around a circle (orbiting) then it is constantly changing ————- but not
velocity
speed
Observations of supernovae from 1998 to present day seem to suggest that
that distant galaxies are moving away from us faster and faster
Describe what happens to stars after their red giant phase until the end of their lifecyle (3 marker)
they become unstable and eject their outer layer of dust and gases
which leaves behind a hot dense sold core known as a white dwarf
White dwarfs then cool to become black dwarfs
Describe what happens to stars after their super red giant phase until the end of their lifecyle (3 marker)
They start to glow brightly again, undergo more fusion, and expand and contract several times
Heavier elements are formed and the star eventualy explodes into a supernova
The supernova leaves behind a neutron star or a black hole
Explain why the velocity of the satellite changes as it orbits earth
(force of) gravity causes the satellite to accelerate (towards the Earth)
the acceleration causes a change in direction
velocity changes because direction changes
Giga
10 to the 9
mega
10 to the 6
tera
10 to the 12
