Astronomy test 3 Word Scramble

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Question	Answer
Describe the In transit theory	God made the light waves closer to us than the astronomical object
Name some problems with the in transit theory	Most observable events never happened - doesn't explain redshifts or CMB - Untestable
Decay in the speed of light	CDK
The CDK theory says	the speed of light was much greater in the past
Problems with the CDK theory are	Early data has large error bars - people would look for data to match a prediction - changing speed of light changes the nature of space
The heating theory says	Starlight heats gas and dust in the galaxy to a temperature of several thousand kelvin in thousands of years
Name some problems with the heating theory	Background radiation is smooth - starlight has many orders of magnitude, so why is CBM so smooth
Baryonic matter	Matter we can interact with
Baryonic matter makes up __% of all matter	4
___________ physics says space isn't fixed	Carmelian
___________ physics says space is fixed	Neutonian
The orbit of _____________ was an issue for astronomers.	Mercury
___________ physics does not need to invoke ________	Carmelian...Dark matter
In 1996, ________ predicted accelerating universe	Carmei
We can find distance with	Parallax
the distance at which 1 AU subtends an angle of 1 arc second	Parsec
Define a parsec	the distance at which 1 AU suptends an angle of 1 arc second
_______________ is the angle by which an object motions moves in an arc second	subtending
1/parsecs	distance
as stars get closer, the parallax angle gets	larger
a ____________ arcsecond is 1/3600 of a degree	arcsecond
there are ____ lightyears per parsec	3.26
the nearest star to the sun is	Proxima Centauri (the system it is in is Alpha Centauri complex)
The two components of star movement are	radial and transverse
The component of star movement that doppler shift measures is	radial motion
Proper motion is used to measure the	transverse motion
_________ star has the largest proper motion of any	Bernard's star
The measure of the total power radiated by a star	Luminosity or total brightness
Light drops off over	distance
Apparent brightness is proportional to	luminosity/distance^2
Apparent luminosity is measured using a __________ scale, which is related to our perception	magnitude
Concerning apparent luminosity, _________ magnitudes are dimmer	larger
__________ is a star large enough for us to image directly	Betelguese
For stars that cannot be imaged directly, size must be calculated from	luminosity and temperature
Luminosity is proportiional to	radies^2 * temperature^4
The radiation from stars is	blackbody radiation
The 7 general categories of stellar spectra are	OBAFGKM
Finding the stars spectral type reveals its	temperature
stars with low temperatures and high luminosity are	giants and supergiants
high temperature and low luminosity	white dwarfs
main sequence stars are fusing __________ into ____________ in their cores	Hydrogen into helium
Luminous main sequence stars are	hot (blue)
less luminous stars are	cooler (yellow or red)
Nuclear fusion requires that ____________________ get close enough to each other to fuse	Like charged Nlei
Nuclear fusion can only happen if the temperature is	over 10 million K
The process that powers most stars is	1) two protons fuse to deuterons 2) two deuterons have a proton added to them to make helium 3 3) two helium 3s add together to make helium 4
Hot blue stars are (larger/smaller) than cool red ones	larger
In order to balance gravity, the core temperature of a high mass star must be	higher
A higher core temperature leads to more	luminosity
______________________ can extend the cosmic distance scale to several thousand parsecs	Spectroscopic parallax
Spectroscopic parallax can only happen if the star	is on main sequence
we can measure mass using	binary stars
two stars orbiting a center of mass around each other	binary stars
name the 3 types of binary stars	Visual - eclipsing binary - spectroscopic binary
we can measure ___________ binary stars by measuring brightness over time	eclipsing
We can measure ____________ binary stars using Doppler shifts	spectroscopic binary
we measure _______ with gravity	mass
Most massive stars are _____ times mass of sun, least massive stars are ______ times mass of sun	100 times... .08 times
Sun's life expectancy is	10 billion years
atoms and small molecules, mostly hydrogen and helium	gas
absorbs light and reddens light that does get through	dust
general term for fuzzy objects in sky	nebula
A dust group that absorbs visible radiation and emits radio radiation	dark nebula
dust cloud glows due to hot stars	emission nebula
Nebula which scatters blue light	Reflection nebula (reflect light)
emission nebulae are made of	hot, thin gas (exhibits distinct emission lines)
The most prominent emission line from emission nebulae is the	H(alpha) line at hydrogen
Stars within nebulae cause dust and gas to	evaporate (light hitting dust particles)
The average temperature of dark nebulae is	a few tens of kelvins
dark nebulae absorb ______ and emit _______	light and emit radio waves
one particularly distinct dark nebula is the	horsehead nebula
the ________ line is the line at which dark nebula emit low energy radiation	21cm
some molecules used to study dust clouds are
The formation of stars goes	dust cloud, cloud collapses, forms a disk, planets form, solar systems form
as the dust cloud collapses, the cloud	breaks into parts, which then fragment
when stuff falls through disksa nd into stars, this is called	accretion
T tauri stars undergo	magnetospheric accretion
In stage 1 of star formation	cloud stars to collapse
for a star to form, ________ must overcome the force of _____________	Gravity, thermal pressure
When a dust cloud is collapsing, the cloud prevents a pressure buildup by converting _______ energy into _______________	thermal energy into infrared and radio photons
Stage 2 of star formation is	cloud fragments begin to collapse
stage 3 of star formation is	the interior of the fragment has begun heating and is 10,000K
In stage 3 of star formation, collisions with particles in the cloud, cause it to	flatten into a disk
When, during star formation, the star first appears on the H-R diagram, it is a	protostar
Stage 4 of star formation is	the core of the cloud fragment is a protostar
Stage 5 of star formation is	Protostars luminosity decreases as temperature rises
Stage 6 of star formation is	core reaches 10MillionK, nuclear fusion beings, now a star
Stage 7 of star formation is	star has reached main sequence, remains until hydrogen burns out
If the mass of the original star is not enough, it becomes	a failed brown dwarf
True or false: when photons strike matter, they exert pressure?	true
If a star is more massive than ______ it blows apart, if it is less massive than _____ it can't sustain fusion	300Msun, .08Msun
Star clusters are the best way to study star formation since	the only variable factor is mass
The two types of star clusters are	open and globular
Open star clusters are	young, loose, sparsely packed, in galactic plane
Globular star clusters are	old, strongly bound, mostly in halo, densely packed
When a star leaves main sequence, what it becomes is based on	its mass
when a star leaves main sequence, if it has high mass it __________ if it has low mass it __________	explode...die out
Stage 8, the star is a	subgiant
stage 9, the star is a	red giant
Stage 10, we achieve	helium fusion
When the core reaches 10^8, what happens	all of the helium in the core fuses within hours.
helium fuses to	carbon and oxygen
After a helium flash, the star becomes	a red giant again, with 2 shells
Stage 11 the star moves	back to the giant branch
stage 12 the star is	a nebula
a nebula has 2 parts	a core and an envelop
stages 13 and 14 are	white and brown dwarves
white dwarfs are	the remaining core of dead stars
the white dwarf limit is	1.4Msun
When a white dwarf in a binary star pair gets hot enough, a	nova forms (due to the accretion disk heating up)
A supernova happens when	an 8 solar mass star cools off
a supernova is ______ times more luminous than a nova	a million
the two types of supernova are	carbon detonation and death of a high mass star
a carbon detonation supernova happens when	a white dwarf accumulates too much mass

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