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140 Cards in this Set
- Front
- Back
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Identify the 2 competing forces that are equal when the star maintains a constant size |
Pressure and the outflow of energy produced by nuclear fusion with the force of gravity |
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TRUE OR FALSE? Outer portions of most stars are never burnt |
True, because gas there never seeps deeply enough to get to the super-hot core. |
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Although the surface of a star expands to become a red giant, is the core contracting or not ? |
Contracting |
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Which five events can trigger the formation of stars and their planets? |
1. spiral density of waves 2. collision 3. tidal influences 4. ionization patterns 5. a heavy short-lived star dies |
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a cloud of gas and dust fragments as it collapses, until pieces collapse to become what? |
an individual star |
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what is the name of the center portion of the collapsing gases that are becoming a star system? AKA Baby star |
protostar |
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What is the reason for “failed stars” ? |
They are too lightweight to get hot enough inside for nuclear reactions to occur |
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When does a star leave the Main Sequence? |
When the centermost part of the core has turned to pure “spent fuel” (it is helium now). |
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The expansion of the star and cooling/reddening of its surface as the visible changes when a star is becoming...? |
a red giant. |
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When something contracts it heats up and spins _________ ? |
faster |
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When something expands it cools and spins ______? |
slower |
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what two places are dust created in the universe? |
1. in red giants 2. supernova death of stars |
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The core contracts so much that temperatures may hit 100 million °K, hot enough to begin helium fusion suddenly. what is this event called? |
helium flash, helium in core ignites |
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After the helium flash, the star settles on the Horizontal Branch on the H-R diagram to burn helium to make what kind of atoms? |
carbon and some oxygen |
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When too much helium becomes carbon, diluting the remaining helium that's fusing, the core again contracts And the outer portions of the star again expand, and cool. which branch doe this define? |
Asymptotic Giant Branch, |
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what is a Nova and what does it cause? |
A nova is a cataclysmic nuclear explosion on a white dwarf, which causes a sudden brightening of the star. |
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what is a Supernova? |
explosive death of a star |
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how many Novaes is one super novae? |
1 million |
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Logically, where do we see most supernovas? ___________________ (in our Milky Way? Or other galaxies?) |
outside the milky and near the center as well |
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what is the cause of a white dwarf going supernova (Type Ia supernova)? |
being it getting too heavy, thus collapsing. |
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If you are asked what kinds of objects can “go supernova,” realize there are two possible answers that would be correct: |
(A) a white dwarf (Type Ia supernova) (B) a very heavy star that is dying (Type II supernova) |
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what is the process that breaks up large atoms during a supernova, undoing previous fusion? |
photodisintegration |
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when does a ball of neutrons (future “neutron star”) forms? |
when the iron core of a dying star collapses (during supernova). |
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what is the difference between the brightness of a supernova to that of a whole galaxy? |
just as bright |
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True or false A pulsar is a kind of neutron star |
true |
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what causes a pulsar to appear to pulse? |
(rotation of beam of radiation coming from it). |
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are the neutron star's North/South poles of rotation the same spots as the North/South magnetic poles? |
no they are not |
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how fast neutron stars rotate? |
it is many times per second! |
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Pick the cause for explosions of x-rays coming from a magnetar |
(strong magnetism ruptures its surface). |
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you can find a neutron star or black holeby what method? |
by observing the gravitational effects on other objects nearby. |
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how can you find the mass of that unseen object in space? |
by studying the motion of the star it is pulling on with its gravity. |
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the similarities and differences an X-ray binary and a Nova? |
X-ray binaries are like novae but involve neutron stars or black holes instead of white dwarfs; both involve mass transferfrom another star. Neutron stars are compacter/stronger so bursts are more violent and more quickly repeat with higher-energy light (X-ray) |
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Fill in blanks When a neutron star or black hole pulls material off another star, (BLANK) can send some of the material away in (BLANK) moving at a significant fraction of the speed of light. |
1 magnetism 2 powerful jets |
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The critical mass that leads a neutron star to collapse to become a black hole is? |
about 3 x Msun |
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method 1 of making a black hole? |
(1) too much weight gain by a neutron star |
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method 2 of making a black hole? |
(2) two neutron stars combine (kilonova) |
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method 3 of making a black hole? |
(3) hypernova death of a very massive star. |
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Pick the likely results of a hypernova |
black hole is formed plus two gamma ray light beams are sent out |
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what am I? A region of force and very strongly warped space, can spin, in center of all galaxies |
black hole |
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a theoretical boundary around a black hole beyond which no light or other radiation can escape. |
Event horizon |
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what are three methods of detecting black holes? |
Gravitational lensing, Accretion disks and jets, Stars orbiting black holdes |
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if a small black hole moves in front of star, it will make the star look (BLANK)? |
Brighter |
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True Or False Space can actually be dragged around the edge of a black hole! |
True |
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used to be thought all galaxies were just small nebulae inside the Milky Way, so they were called... |
Spiral Nebulae |
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Method to finding spiral nebulae ? |
Find stars in those spiral nebulae, then find distances to those stars, and that gives distances to the spirals |
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Variable Star |
A variable star is a star whose brightness as seen from Earth (its apparent magnitude) fluctuates and changes. |
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which aspect of Cepheid variable stars tells you their true brightness? |
their pulsation period does |
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how does the period-luminosity relation works for Cepheid stars? |
slower the pulsation, brighter the Cepheid! |
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Cepheids help us get the (blank) of other galaxies because of the brightness |
distance |
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Identify the difference between Population I and Population II stars |
One is early first-generation stars while other is more recently made The surfaces of the earlier generation show fewer heavy types of atoms present (“heavy elements”) |
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Which component of a spiral galaxy matches a description you are given? |
bulge, disk, halo, and nucleus/core |
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What kind of stars make up the bulge and halo of a galaxy? |
the oldest |
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2nd-generation stars formed from the mix are found where in the galaxy |
the disk |
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is flat, has gas/dust, has spiral arms, and has stars both young/old? what is it? |
disk in galaxy |
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TRUE OR FALSE Halo, bulge, and nucleus are round, have no spiral arms, are essentially just old stars, and have no appreciable gas/dust. |
True |
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what is the spherical region around the galaxy and overlaps all the other components. |
halo of galaxy |
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TRUE OR FALSE The nucleus is the most dense central part of Bulge. Bulge, nucleus, and surrounding halo contain old red stars. |
true |
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what kind of orbits does stars in the halo, bulge, and nucleus usually have? |
random orbits of all kinds |
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Does the dark halo component of the galaxy extends far beyond the visible edges of our Milky Way galaxy? |
yes |
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correct time it takes for the Sun to orbit our galaxy |
225 million years |
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spiral arms or spiral density waves as being waves of (BLANK) rotating around the galaxy. |
pressure |
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The reason spiral arms shine brightest? |
They have younger stars, which are brighter |
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parsecs, kiloparsecs, and megaparsecs are all units of what? |
distance |
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what kind of galaxy our Sun is in? |
Milky, which is a spiral galaxy |
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what the parts are possessed by a spiral galaxy |
a disc, spiral arms, bulge, halo. |
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what type of galaxy is it if If the bulge of a spiral galaxy is elongated? |
barred spiral galaxy |
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Elliptical galaxy does not have two qualities that a spiral galaxy has what is it? |
ellipticals lack a disc and spiral arms. |
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what is the reason elliptical galaxies have a color between gold and red? |
have both old and young stars |
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The largest galaxies are always elliptical galaxies? |
more stars and more collision of big galaxies |
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Do stars orbit more randomly in elliptical galaxies? |
yes |
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galaxy cluster |
group of galaxies |
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galaxies can come in groups of a few galaxies up to many thousands |
“rich” cluster |
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a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction. |
galaxy |
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a bar-shaped structure composed of over 400 billion stars that contains planets such as earth and jupiter |
Milky Way |
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What is the galaxy group that includes the Milky Way. It comprises more than 54 galaxies, most of them dwarf galaxies. |
Local Group |
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is a structure that consists of anywhere from hundreds to thousands of galaxies bound together by gravity with typical masses |
Galaxy Cluster |
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a cluster of galaxies which themselves occur as clusters. |
Super cluster |
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The vast empty spaces between filaments (the largest-scale structures in the Universe), which contain very few, or no, galaxies. |
cosmic voids |
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a network of filaments of dark matter, believed by many astronomers to form the basis of the universe |
Cosmic Web |
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All existing matter and space considered as a whole; the cosmos. Is believed to be at least 10 billion light years in diameter and contains a vast number of galaxies; it has been expanding since its creation in the Big Bang about 13 billion years ago. |
The Universe |
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If astronomers plot the “rotation curve” for a galaxy, this means they plot what? |
how the speeds of stars are different as you look at starsfurther and further from the center of the galaxy. |
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If the rotation curve stays high and “flat” even for objects orbiting out past the visible edge of the galaxy, it means there isextra material beyond that edge that you are failing to see. What is it called? |
Dark Matter |
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Redshifts and blueshifts of the light of galaxies that are orbiting in groups/clusters tell us what? |
the mass of the cluster |
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Active galaxies emit a lot more (BLANK) than normal galaxies of the same size usually do and Evidence of (BLANK) of material demonstrates why it is active galaxy |
light, acceleration |
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Seyfert galaxies and radio galaxies are what type of galaxies ? |
active |
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what kind of object often has two plumes or jets of high-speed particles coming from it? |
active galaxy” or “radiogalaxy. |
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What is the cause of the activity in an “active galaxy” ? |
supermassive black hole |
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are believed to be powered by accretion of material into supermassive black holes in the nuclei of distant galaxies, making these luminous versions of the general class of objects known as active galaxies. |
Quasars |
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what is brighter than a supernova. Brighter than the brightest galaxy? |
Quasar |
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The power source at the center of an active galaxy is what? |
supermassive black hole that is feeding. |
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What has a mass that is from 100,000 up to billions of times the Sun's mass? |
Black Holes |
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Roughly 30 million miles (45 million km), about 30 times the diameter of the Sun is the diameter of what? |
supermassive black hole |
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What causes tails of material to be torn off a galaxy during interaction or a near miss with another galaxy? |
tides from the force of gravity |
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What color will a galaxy have if it has a lot of new stars that have been born? |
white or light pink |
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what two kinds of stuff have existed in the universe since nearly the beginning of time? |
gas and dark matter |
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TRUE OR FALSE Young galaxy (protogalaxy) makes lots of stars at a much faster rate than normal galaxies do today. |
True |
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what is the reason why spiral arm shapes form in the disk of a spiral galaxy? |
spin of galaxy stretches lumps into curved shapes |
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what is a factor that has led to elliptical galaxies being elliptical instead of spiral? |
Basically they have a more violent past involving winds from black hole activities and collisions with other galaxies! |
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When galaxies collide, spiral galaxies can be converted into what type of galaxies ? |
elliptical galaxies with the spiral arms |
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which phenomenon can create false images of a galaxy or quasar |
a gravitational lens |
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Why does the gravitational lenses exist and causes them to produce false images? |
gravity makes space warped or “curved” |
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the science of the origin and development of the universe |
Cosmology |
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the world or universe regarded as an orderly, harmonious system. |
cosmos |
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What is the reason further and further galaxies looker redder and redder in color? |
they are moving faster away from us |
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Further galaxies move faster away from us is what law? |
Hubbles law |
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Is space stretching or shrinking? |
Stretching |
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Does the universe have an edge or center ? |
no |
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Why would the sky still be dark at night even if the universe is filled with an infinite number ofstars? |
The universe is too young for light from infinity to have reached us. |
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what tries to slow down the expansion of the universe? |
gravity |
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nonluminous material that is postulated to exist in space and that could take any of several forms including weakly interacting particles |
dark matter |
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a theoretical repulsive force that counteracts gravity and causes the universe to expand at an accelerating rate. |
dark energy |
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what does dark energy cause? |
increasing rate of expansion of the universe |
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a contraction of the universe to a state of extremely high density and temperature, hypothesized as a possible scenario for its demise. |
big crunch |
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The universe began very hot, but like anything that expands, it has done what? |
cooled down |
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Identify the reason radiation lost its dominance |
the expansion of the universe stretched the wavelength of light until high-energy light became very-low-energy light |
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3 eras of universe |
dark matter era, radiation era and matter era |
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what are the smallest possible measurements of length of space and length of time? |
Planck Length; Planck Time |
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Physicists favor the theory that there was an extreme sudden burst of expansion of the universe because of what? |
inflation |
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when the universe had finally cooled down enough, particles could come together to make the nucleus of an atom. what is this called? |
nucleosynthesis |
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what are the two types of atoms (elements) that naturally formed in significant amounts during the Big Bang? |
hydrogen and helium |
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is a supernova remnant and pulsar wind nebula in the constellation of Taurus. |
Crab Nebula |
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Supernova |
explosive death of a star |
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Milky way is the entire Universe. who thought of this concept? |
Harlow Shapley |
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Milky way is not the only galaxy and the M.K. Galaxy is small are the thoughts of who? |
Heber Curtis |
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Henrietta leavitt discovered what? |
period-luminosity relation |
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Standard candles |
technique and method that shows true brightness of star |
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Extragalactic astronomy? |
study of places outside our own milky way |
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mega parsecs |
one million parsecs |
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gigaparsecs |
one billion parsecs |
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irregular galaxies are what color and what happens? |
blue, short lived galaxy because they are so heavy |
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Safer galaxies are spiral galaxies with what kind of nucleas |
extra bright |
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radio galaxy emits what? |
plumes of material like radio waves |
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Doppler effect is used to find what of a astrologic object? |
speed |
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galactic canibalism |
large galaxies eat small galaxies |
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galaxies that show effects of recent collision |
starburst galaxies |
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what two things are needed to form a spiral galaxy? |
dark matter and gas |
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small, very few stars, old stars |
dark galaxies |
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is everything that is connected to us by space and time and is what is made up of the universe and cosmos |
cosmology |
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Found distance of galaxies, and knew there were galaxies outside milky way, and used the method of redshift |
Edwin Hubble |
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TRUE OR FALSE there is no edge to the universe and is infinite |
true |
