Earth and Space
Astronomy
the study of celestial objects & processes
Cosmology
the study of the history and structure of the entire universe
galaxy
a system of millions of stars held together but gas, dust held together buy gravitational force
SI units (Meters, kilometers and seconds
Logarithmic thinking
a way of understanding numbers by focusing on how much larger or smaller they are in powers of ten, rather than their exact values
Lightyears - Measurement of length/distance
Distance light will travel in a year
1 year = 9.46000000000000000
Speed of light = speed of ALL electro magnetic radiation
Prior theory's
celestial bodies were gods
influenced by religion
Background
Edwin Hubble
Galaxies million of light years from earth
Spectral lined distance by starlight measured by wavelength
proving that galaxy's were moving away from earth
Space was expanding
distances between galaxy's increasing
galaxy’s would collide
Light Spectra
Chemical composition of stars
high frequency = short wavelength
continuous spectrum - full
emission spectra - missing frequencies
absorption - continuous - not absorbed by gas continues - emission
every element has its own unique spectra
Viewed on electromagnetic spectrum
energy directly proportional to frequency and inversely proportional to wavelengths
Small wavelength = Higher frequency - Have more energy
*Formation of spectra
The photons of electromagnetic radiation
created in the middle of a star interact with the
atoms in the outer layers of the star as it is
emitted.Electrons that gain energy from interacting
with photons will move to a higher energy
level. As these electrons in a higher energy
state are not stable they will fall back to a lower
energy level and release the extra energy as a
photon.The interaction of the photons with the atoms
in the outer atmosphere of a star produces two
types of spectra – absorption and emission
Stars emit electromagnetic radiation, including
visible light, across a range of wavelengths.
A stars temperature effects its colour
The hotter the star the more energy it has and the bluer the colour
Hotter stars have shorter peak wavelengths and
appear blue or white, while cooler stars have
longer peak wavelengths and appear red or
orange.
Scientists analyze a star’s spectrum and peak
wavelength to estimate its surface temperature
Temperature is a measure of the amount of kinetic energy of particles in a substance
all colours emit white light
Most galaxies are moving away from us
The doppler effect
The Doppler effect is the change in frequency
of a wave in relation to an observer who is
moving relative to the wave source.Pitch and frequency are directly proportional
Pitch increase - frequency increase
Stars release a continuous spectrum - which is a series of wavelengths forming either an absorption or emission spectra
when something is moving away from us at a lower frequency we get a red shift
When moving toward us with a higher frequency we see a blueshift
Redshift
The further away a galaxy is the faster it is travelling the greater the redshift
evidence for the expansion of the universe
the speed at which a star or galaxy is moving away from us
aerometer is the one galaxy that is moving towards us and has blue shifted
the spectral lines have moved toward the red or blue side - red shift or blue shift
13.8 years ago the universe began as an extremely hot dense singularity
Any temp above 0 Kelvin will emit electromagnetic radiation
the hotter the object gets the shorter the electromagnetic waves
hotter = decrease wavelength increase frequency
nucleus made up of protons and neutrons
prior to 380,000 10 to the 12 kelvin glowing superheated fog after 380,000 universe had cooled to 3000 degrease
1965 detect a faint microwave signal coming from all directions in space
known as recombination
protons + neutrons produces photons
photons can move through the universe
No explosion in the big bang - supporting the idea that space has been expanding since the beginning of time
What is the big bang - theory
not an explosion
Expanding of the universe
Time = 0
Incorrect Theory - Steady State
universe in a state of eternal expansion
new matter created to fill gaps
universe remain uniform
13.8 billion years ago = big bang
Singularity
universe expanding
density of matter decreasing
Big bang = expansion of space
redshift = galaxy's moving further away/receding shifting away
Recession velocity is directly proportional to distance
= 𝑣 =𝐻0×d
gradient = (rise/run) /constant = hubbles constant = Ho
CMB = after glo from the big bang
expansion of the universe caused the wavelength to increase
destroyed steady state model theory
predicted by math’s
evident from science
Need to define
cosmological red shift
CMB radiation
every element has its own unique spectra
Viewed on electromagnetic spectrum
energy directly proportional to frequency and inversely proportional to wavelengths
Small wavelength = Higher frequency - Have more energy
*Formation of spectra
The photons of electromagnetic radiation
created in the middle of a star interact with the
atoms in the outer layers of the star as it is
emitted.Electrons that gain energy from interacting
with photons will move to a higher energy
level. As these electrons in a higher energy
state are not stable they will fall back to a lower
energy level and release the extra energy as a
photon.The interaction of the photons with the atoms
in the outer atmosphere of a star produces two
types of spectra – absorption and emission
Stars emit electromagnetic radiation, including
visible light, across a range of wavelengths.
A stars temperature effects its colour
The hotter the star the more energy it has and the bluer the colour
Hotter stars have shorter peak wavelengths and
appear blue or white, while cooler stars have
longer peak wavelengths and appear red or
orange.
Scientists analyze a star’s spectrum and peak
wavelength to estimate its surface temperature
Temperature is a measure of the amount of kinetic energy of particles in a substance
all colours emit white light
Most galaxies are moving away from us
The doppler effect
The Doppler effect is the change in frequency
of a wave in relation to an observer who is
moving relative to the wave source.Pitch and frequency are directly proportional
Pitch increase - frequency increase
Stars release a continuous spectrum - which is a series of wavelengths forming either an absorption or emission spectra
when something is moving away from us at a lower frequency we get a red shift
When moving toward us with a higher frequency we see a blueshift
Redshift
The further away a galaxy is the faster it is travelling the greater the redshift
evidence for the expansion of the universe
the speed at which a star or galaxy is moving away from us
aerometer is the one galaxy that is moving towards us and has blue shifted
the spectral lines have moved toward the red or blue side - red shift or blue shift
13.8 years ago the universe began as an extremely hot dense singularity
Any temp above 0 Kelvin will emit electromagnetic radiation
the hotter the object gets the shorter the electromagnetic waves
hotter = decrease wavelength increase frequency
nucleus made up of protons and neutrons
prior to 380,000 10 to the 12 kelvin glowing superheated fog after 380,000 universe had cooled to 3000 degrease
1965 detect a faint microwave signal coming from all directions in space
known as recombination
protons + neutrons produces photons
photons can move through the universe
No explosion in the big bang - supporting the idea that space has been expanding since the beginning of time
age of the universe = 13.8b years
+or- 0.2 (million of year error)
Big Bang theory evidence
Cosmological
Redshift
Galactic redshifts demonstrate
that all galaxies are moving
away from each other, pointing
back to a single initial point.
Cosmic Microwave
Background Radiation
CMB radiation glow acts as a
snapshot of the hot, dense
early universe right when
atoms first formed.
*Light Element
Abundance = supplementary
The exact 3:1 mass ratio of
primordial Hydrogen to Helium
perfectly matches theoretical
nuclear calculations
Beginning is a = Singularity
Evolution
0s = singularity = all laws of physics break down
space time and matter originate from an infinitely hot and dense point (do not know exactly)
0 to 10-43 s
Planck Tim
Temperature > 10³² K
All four fundamental forces
were unified
10-43 to 10-36 s
Grand Unification
Gravity separates out
Particles and antiparticles
began to form
10-33 to 10-36 s
Inflation
Exponential expansion
increasing space by 1026
10-32 to 10-12 s
Electroweak Epoch
Strong force separates out
10-12 to 10-6 s
Quark Epoch
Formation of quarks
10-6 to 1 s
Hadron Epoch
Quarks combine to form
protons and neutrons
1s to 3 min
Nucleosynthesis
Formation of atomic nuclei
as protons and neutrons
combine
3 mins to 380 000 years
Photon Epoch
photons separates out from dense plasma universe
380 000 years
Recombination
Atomic nuclei form
Photons decouple and CMB
radiation is created
Universe is transparent
100 to 200 million years
Cosmic Dawn
Gravitational forces cause
matter to condense
First stars ignited
200 million years to
present
Nucleosynthesis
Galaxies formed
Heavy elements formed
Present
Dark Energy
Accelerations
Dark energy dominates
Accelerating cosmic
expansion=68% of the universe
expansion of the universe is speeding up
Future
Big Freeze
Widely accepted
Universe continues
expanding and it becomes
extremely cold and dark
Luminosity is the total amount of energy a
star releases each second across all
wavelength of the electromagnetic spectrum.
Luminosity is the actual brightness of a star.
Luminosity of a star depends on:
temperature, i.e. hotter stars emit more
energy and light.size (radius), i.e. larger stars have a
greater surface area emit more light.
The brightness of a star is referred to as
magnitude.
The brightness of a star by either its
▪ Apparent magnitude
▪ Absolute magnitude
Absolute magnitude is a measure of the star’s actual brightness.
The absolute magnitude of a star measures how bright a star would appear to us if it was observed at
the same distance from Earth. The distance used is 10 parsecs1 parsec = 3.26 light years
10 parsec = 32.6 light years
Absolute brightness depends on a star’s luminosity, not its distance
Stars emit light across a range of wavelengths.
The colour of a star provides information
about its surface temperature.Blue stars are the hottest
Red stars are the coolest
When light from a star passes through the
cooler gases in a star's outer atmosphere,
specific wavelengths are absorbed, producing
an absorption spectrum.By analyzing these dark absorption lines together with a star's colour, astronomers determine the
star's temperature and identify the elements present in its atmosphere
Cool stars → emit infrared and red visible light → appear red
In-between stars → emit light across a range of spectrums → appear orange, yellow or white
Hot stars → emit ultraviolet and violet visible light → appear blue
Spectral Class is a system that indicates the elements present in the star, the temperature and the
colour of the star.
There are seven classes of stars – O, B, A, F, G, K,M
Gravitational Fields and Force
A gravitational field is a type of force field that exists around any object (or particle) with
mass, i.e. where anything placed in the field may be pulled towards the center of the
object.
When another object with mass enters a gravitational field, a gravitational force exists
between the two objects pulling them toward each other's centers
greater the mass = greater the curvature
gravitational field strength = force of 9.8N per kg applied
During the inflation epoch in the early stages
of the universe microscopic variations in
density existed.Slightly denser regions exerted stronger
gravitational forces, establishing the ‘cosmic
seedsThe Cosmic Microwave Background (CMB)
captures the universe 380,000 years after the
universe began, serving as evidence of cosmic
structure origin
Gravitational forces can act over very large
distances.
Over billions of years gravitational forces between
the ‘close’ stars have caused them to clump
together and form galaxies
The size and shape of galaxies varies across the
universe
2 atomic light nuclei force together from a single heavier nucleus
Energy Source = power source of all main sequences stars
By products = clean non - toxic helium produces massive energy yields
Extreme temp must reach 15 million c
Immense pressure forces pack hydrogen nuclei (just 1 proton) extremely close together
stars are made mostly of hydrogen and helium
gravitational forces pulls the atoms inward causing the stars core to become extremely dense and hot and under immense pressure
these conditions allow nuclear fusion reactions to occur where hydrogen nuclei combine to form helium
release immense energy creating outward force due to radiation pressure
the size and structure of a star are determined by the balance between two opposing forces - inward gravitational forces
Hertzsprung Russell diagram shows the relationship between the brightness and the temperature of stars
Stars are formed in clouds of gas and dust known as nebulae
Nuclear reactions at the center of stars provides enough energy to make them shine brightly for many years
The exact lifetime of a star depends very much on its size
NEEDS HIGH TEMP HIGH DENSITY FOR NUCLEAR FUSION
Stellar ignition - when hydrogen begins to fuse with helium
Hydrogen nuclei fuse electrostatic repulsion is overcome
gradational force and radiation pressure are equal equilibrium = A main sequence star = forces =0
Gravitational force = the inward force attempting to collapse the stars mass forces
Radiation Pressure = The outward force generated by energy by nuclear fusion
most stars spend most of there life as a main sequence
All stars follow cycle Nebula - protostar - main sequence star
Equilibrium = forces are balanced
Low-mass main sequence star
nebula → protostar → low mass main sequence star → white dwarf → black dwarf (theoretical)
Medium-mass main sequence star
Nebula → protostar → medium-mass main sequence star → red giant → planetary nebula → white dwarf → black dwarf (theoretical)
High-mass main sequence star
nebula → protostar → high-mass main sequence star → red supergiant → supernova → neutron star or black hole
Lifecycles of stars are base on the initial mass
Red giant
is formed when nuclear fusion reactions occurring in the core of a medium-mass main sequence star slow down and stop
Gravitational forces cause the core to contract increasing the pressure and tempreture which allows fusion to continue in a shell around the core
the increased energy causes the outer layers of the star to expand and cool making the star larger and redder in colour
A supergiant star forms when a high mass main sequence begins to run out of hydrogen in its core causing changes in the nuclear fusion reaction occurring inside the star
Blue stars and supergiant's
Blue star
forms when a high mass star begins its main sequence stage
large mass creating strong gravitational forces producing high pressure and temp
can cool and become red giant or straight to supernova
blue = hotter
A planetary nebula is an expanding glowing shell of gas released from the outer layers of a red
giant near the end of its life
gas emitted and left with a white dwarf = old core of the star no more reactions
as it runs out of fuel gravitational forces cause the outer layers to be expelled into space leaving behind the hot core that becomes a white dwarf
A white dwarf dorms after a low - medium mass star ahs expelled its outer layers creating a planetary nebula the hot core of the star is extremely dense and initially very got appearing white due its high surface temperature
no longer producing energy through nuclear fusion
over time the star slowly cools and becomes less bright
A black dwarf is the final theoretical theory
Supernova
giant explosion occurring at the end of a high mass stars life cycle
Neutron star
core left after by a supernova
gravitational forces compress causing protons to combine