astronamy pt3 Flashcards
geocentric model
the idea that the earth was at the center of the solar system
also earth was thought to be stationary because they couldn’t feel it move
heliocentric model
the idea that the sun was at the center of the universe
Nickolas Cupernicus
supported by astronomy
order of planets
mercury, Venus, Earth, mars, Jupiter, Saturn, Uranus, Neptune
Kuiper belt
disk shaped regions beyond Neptune commets asteroids lot a lot of ice bodies
Oort Cloud
cloud with ice bodies surround the sun
retrograde motion
apparent motion of a planet in a direction opposite that the other bodies in the system are going in
an illusion created by the look of the skies
all the other planets are going faster so it looks like it’s going backwards
if the motion is normal and not retrograde it is called prograde
AU
astronomical unit is the distance from the earth to the sun= 1 AU
To find another planets Au you just take their distance to the sun and divide it by 1 AU (149.6 million km)
light years
the distance light travels in a year
can measure other distances in space
parsec
3.26 light years
scientific notation
a way to write high numbers by writing a number between 1-9 then writing 10 exposent the times you want to times the number by 10
the HR diagram
a tool to show different relationships between stars
it measures luminosity and temperature
at different ages/stages at the same time
each star is a dot
y axis= luminosity
x axis= surface temp, right- lower temperature
used to show the elevation of stars and investigate their properties
main sequence star on the HR diagram
a star with a predictable relationship between brightness and temperature
would mean that if its hotter than its brighter
or cooler then its dimmer
throught the middle of the HR
giants
cool but very luminous
very large
has the same energy as the main sequance but are bigger
just above the main sequance the the right
super giants
very luminous more than giants
very large
top right corner
white dwarfs
very hot but dim so very small
bottom left corner or HR
star evolution
stars spend 90% of their lives in the main sequence burning helium and hydrogen
then then become giants or super giants when they finish burning hydrogen and begin burning just helium
white dwarfs is the last step for low intermediate mass stars
stellar spectra
the use of a spectroscope to look at the light energy of a star to determine it’s composition
can find out what elements are in it and what their temperatures are
spectroscope
split’s light energy into a pattern of colors (visible light) for observation
each element shows a recognizable pattern of lines
physical property
the big bang
approx 13.7 billion years ago there was a single atom (singularity)
and all matter and space created in an instant from the singularity
it keeps growing
energy converted into matter in clumps created protons neutrons electrons and atoms
the process of the big bang
atoms formed creating hydrogen and icetopes
the universe was 75% hydrogen and 25% helium (like now)
years later
stars and galaxies formed
our solar system was formed approx 4.6 billion years ago
misconceptions of the big bang
there was no explosion- only an expansion
there was nothing before the singularity
the singularity was not a burning flame
expansion started at time 0
how does Hubble’s law prove the big bang
he proved that the galaxies are always expanding and red shift
how does background radiation prove the big bang
people noticed that were was radiation static that was spread across space
believed to be left over from the big bang
hubble’s law
Hubble proved a expanding universe by noticing that other galaxies are red shifted proving that they are going away from us
he also noticed that the further away the galaxy the faster is is moving away
proving the expanding universe
Doppler shift
the change in frequency/ wavelength of a wave because of the movement in the source
if a source is coming to you the waves become blue shifted and become more frequent
as the source is going away it becomes red shifted and the wavelength become less frequent
spiral galaxy
shaped like a flattened disk
has one or more arms in a spiral
our solar system is on one of the arms of our galaxy
can have nebulae
elliptical galaxy
about 1/3 of galaxies massive blobs of stars round or elliptical in shape no gas so no new stars can form largest and smallest galaxies are elliptical
irregular galaxy
not in any other category
chaotic
found near spirals
the spirals mess up their shape
comet
made of carbon hydrogen oxygen and nitrogen
when it is far from the sun it is a cold dark ice ball
are a few km long also made of dust
surrounded by hydrogen gas creating a glow
when they travel to the sun the icy shell evaporates falling back to create a tail as well as creating a coma
tails
as the comet evaporates the ice goes back to create one tail
there is also another tail made of dust that leans one way
coma
when the ice evaporates on the comet some of it stays around and gives it a fuzzy look
short orbits
years or decades
is always prograde motion
comes from the Kuiper Belt
long orbits
century- a thousand years
can be retrograde or prograde
from the oort cloud
kuiper belt
a region of the solar system beyond the orbit of Neptune, believed to contain many comets, asteroids, and other small bodies made largely of ice.
