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Earth Science Unit 2: Astronomy - Coggle Diagram
Earth Science Unit 2: Astronomy
Vocabulary
Astronomer
scientist
studies celestial body
Constellation
group of stars
form a pattern
Electromagnetic Radiation
energy
travels in waves (air)
Electromagnetic Spectrum
all wavelengths of Electromagnetic Radiation
Frequency: # of waves passing a point each sec.
Types
Gamma Ray
shortest wavelengths
penetrating
Infrared Light: wavelengths b/twn radio and light waves
Radio Waves
longest wavelengths
lowest frequencies
Microwaves: shortest wavelengths
Ultraviolet Light
wavelengths b/twn visible light and x-rays
harmful to people
Visible Light
wavelengths b/twn infrared and ultraviolet light
can be seen by humans
Wavelength: distance b/twn two crests of troughs
Light-year
distance light travel in a yr.
9.5 trillion km
Telescopes
Catadioptric Telescope
uses mirrors and lenses
collect and focus light
Radio Telescope: collects radio waves
Reflecting Telescope
uses mirrors
gather and focus visible light
Refracting Telescope
uses convex lenses
gather and focus visible light
Space Telescope: orbits above Earth's atmosphere
Planet
space object
orbits a star
smaller objects orbit it
Spectrometer: breaks light into different wavelengths, or colors
Asterism
group of stars, visible from Earth
Black Hole
super-dense
remnants of supergiant exploding
Neutron star
remnant of exploded supernova
Nuclear Fusion Reaction
releases huge amt. of energy
two nuclei form a bigger nuclei
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Parallax
calculate dist. between stars
Star: sphere of gases; produces light through nuclear reactions in core
Red Giant
stage in star's life
helium core contracts and hydrogen core expands
Supernova
explosion
core of star is mostly iron
White Dwarf
small-medium
collapsed and stopped fusion
Electromagnetic Radiation
Light
energy of light is tied to wavelength
diif. colors have diff wavelentgsh
visible light
invisible light
unseeable form of electromagnetic radiation
emitted in form of energy
energy can be neither created nor destroyed
everything emits light
when electrons gain or lose energy it emits a diff energy/color
Spectrometer
help celestil made of
recognize specific colros
longer wavelength: red
shorter wavelength: blue
Speed of Light
fastest thing in the universe
300,000,000 meters per second
Light-year
unit of distance
how far light travels in a year
9.5 trillion km
still takes time for light to reach us from space
takes light from the Sun 8 minutes to reach us
we are seeing light as it was millions of years ago
Telescopes
Optical Telescopes
Refracting Telescopes
earliest telescopes
refract light
use glass lenses
Catadioptric
use glass lenses and mirrors
Reflecting Telescopes
Isaac Newton invented
use curved mirrors
reflect light
mirrors are lighter than glass
can be bigger than refracting and catadioptric
need less support from telescope
Radio Telescopes
look like satellite dishes
built to collect and focus radio and microwaves
first invented in 1500s
Galileo improved designs
Space Telescopes
no atmospheric resrictions
Hubble Space Telescope
took first disk image of a star that is not our Sun
Astronomers
Ancient Astronomers
stars were how ancient people kept track of time
knew when to harvest plants
planned religious traditions around celestial bodies
Galileo
Discoveries
Planets
Jupiter has orbiting moons
moon has craters
1st person known to look at the moon
Venus has phases like the moon
Stars
milky way consists of many stars
dark spots move across Sun
more stars than our eyes can see
observations backed up Copernicus' theory
Greeks made many advances in astronomy
identified constellation (named for myths/stories)
discovered planets (wanderer in Greek)
Modern Telescope Observations
Amateur
bands of Jupiter's atmosphere
rings of Saturn
polar caps on Mars
Professionals
rarely look through eyepiece of telescope
computers attached to telescopes process images
may take months to analyze all data collected
use spectrometers to analyze the light from the telescope
how hot the star is
elements in star
movement of the star
shifting of the dark lines
Hertz-Sprung Russel Diagram/ H-R Diagram
scatter graph
shows classes of stars
luminosity
absolute magnitude
color
stars that are reddish are cooler
bluish stars are cooler
effective temperature
1910
Main Sequence
fusing hydrogen and helium
vertical axis: luminosity
horizontal axis: temperature
white dwarfs
duller than temp. suggests
dull because of small size
brightness comes from stored heat energy
Red Giants
brighter than temp. suggests
brighter because they are so big
Stars
Constellations
patterns shift as Earth rotates
also shift with the seasons
people see different constellations at different times of the year
Nuclear Fusion
hydrogen and helium make up majority of star core
pressure in a star's core creates nuclear fusion
energy produced from nuclear fusion is pushed outward to the surface
Classification
Color
color suggests temperature
most common
color suggests temperature
cooler stars are red
hot stars are blue or bluish white
warmer stars are yellow of orange
Temperature
bigger stars produce more energy therefore more heat
Lifetime
known because of data from telescopes
life cycle similar to animals
changes in size, color, and class
Formation
Nebula
clouds of gas and dust
Pillars of Creation: gases come together; form a star nusery
Main Sequence
able to balance force of gravity w/ force of nuclear fusion
bigger stars burn energy faster; leave sooner
life cycle similar to animals
Formation
Nebula clouds of gas and dust
Pillars of Creation: gases come together; form a star nursery
Blue Giant
exhausted hydrogen
gravity takes hold and star collapses inward
outer layers expand and cool
Red Giant
formed from Blue Giant
when all helium burns out diff. things happen depending on size
typical stars collapse
White Dwarf
eventually just fade out
Red Super Giant
fusion continues after helium is gone
fuse into iron atoms
no more elements to fuse; star collapses
Supernova
can produce heavier atoms than iron
can shine as brightly as a galaxy for a few seconds
Neutron Stars
smaller stars become neutron stars after Supernova
made almost entirely of neutrons
no electrical charge
Measuring Distances
problem for astronomers
Parallax
apparent shift in position; takes place when position of observer changes
astronomers start in one position; look at a star from the biggest possible observing distances
as Earth moves around the Sun, astronomers observe the star from the same position on Earth
use brightness to determine distance
Galaxies: biggest group of stars
Andromeda Galaxy
closest galaxy to us
spiral galaxy (similar to us)
Three Types
Spiral
spin
contain lots of gas, dust, and young stars
Elliptical
most contain very little gas or dust
all has formed stars already
can contain over a trillion stars
mostly old stars
astronomers believe that form from two galaxies colliding
Irregular
not clearly elliptical or spiral
were once spiral or elliptical but became deformed
Dwarf Galaxies
mostly irregular; some can be spiral/elliptical
most common in the universe
small and dim; don't see many from Earth
near bigger galaxies; sometimes collide or merge
Milky Way Galaxy
we can only see a portion
contains 100-400 billion stars
spiral galaxy
Universe
Human Understanding of the Universe
Ancient Greeks
everything revolved around Earth
Galileo's telescope showed rotate around Sun
Edwin Hubble
discovered what scientists were calling nebulas were galaxies
distance to Andromeda Galaxy
showed true expanse of universe
combined his data with redshift data from others
Hubble's Law: further away a galaxy is the faster it is moving
data showed shifts; led to possible formation
Redshift
arrangement of dark bands allows astronomers to see distance
absorption bands tended to shift to red end of spectrum
spectrums have dark bands; light is absorbed by elements
occurs when object moving away
Doppler Effect: increase/decrease in frequency of EM radiation
Expansion
Hubble's law is helpful
galaxies stay same size but spread out
space is stretching
Formation of Universe
Big Bang Theory
most widely accepted theory of formation
uni. started 13.7 billion yrs. ago
universe was condensed
big explosion
universe began expanding
contained all matter
After
hot and dense
began to expand and cool
atoms could begin to fuse
enough energy to form hydrogen
matter wasn't evenly distributed
clumps of matter were together b/c gravity
clumps became stars then galaxies and other celestial bodies
Dark Matter
emits no EM radiation
most astronomers think makes up 80% of universe
has gravity
how we know it exists
Gravitational lensing
light is bent around massive obj.
little known about
could be regular celestial bodies
won't cover all dark matter
could be something irregular
Dark Energy
cause of universe expansion
some scientists think it makes up 72% of matter
Telescopes
Ground Based
Refracting
examine visible light
our moon
planets in our solar system
double stars
consists of
objective
diameter is called an aperture
lenses
can straighten images
eyepiece
controls magnification
Catadioptric
better error correction
uses mirrors and lenses
Catadioptric Dialytes
earliest Catadioptric
singel refractor objective
Hamiltonian was first
Full-Aperture correctors
two full diameter lenses in front of primary mirror
originally for wide fields of view
Schmidt Corrector
1st full diameter correction plate
1st used in Bernhard Schmidt's cameras
photographic telescope
Schmidt-Cassegrain
sub-type
big commercially
mostly for amateurs
long focal length--> smaller field of view
Reflecting
deep space observation
can study infrared and ultraviolet light
primary mirror is concave
inverts images
focuses images
glass covered in reflective metal
used by most astronomers
not meant for amateur use
advantages over refractors
easier to make
better quality images
tubes can be shorter
cheaper
wavelengths don't disperse
Largest
Hubble is the largest reflector in space
Gran Telescopia Canarias is the biggest on Earth
VLA
Very Large Array Telescopes
Karl G. Jansky VLA Observatory in New Mexico
has 27 25 meter telescopes
function as interferometer
interferometer
merge two or more light sources to study
used to oberve blackholes and protoplanetary disks
NASA's Great Observatories
Hubble Telescope
reflector (visible light, ultraviolet, and near infrared)
deployed in 1990
James Webb Telescope
replaced Hubble
infrared
meant to complement and extend Hubble telescope's discoveries
Compton Gamma Ray Observatory
studies supernovae and black holes
heaviest astrophysical load ever carried
Gamma Ray telescope
Chandra Telescope
x-ray telescope
studies Sun, stars, supernovas
Spitzer Telescope
Infrared Telescope
detected birth of stars
lost full functions due to liquid helium loss
H-R Diagram
Background
1800s scientists started studying absoprtion spectra of stars
absorption spectrum
wavelengths of light are absorbed
dark bands appear on the spectrum
use spectra to classify stars
also use luminosity/brightness to classify stars
how bright it seems from Earth
distance from Earth
early 1900s Hertzsprung and Russel decided to combine the two classification methods
started as muinosity against spectral classification t
became luminosity vs. temperature