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PH 109 Final Part 2

QuestionAnswer
What causes the outward pressure that balances the inward pull of gravity in a black hole? nothing
Most of the elements that make us up were produced in supernovae
What is the single most important characteristic in determining the course of a star's evolution? Mass
Red stars are ____ than blue stars cooler
What causes the outward pressure that balances the inward pull of gravity in a normal star? The outward flow of energy
What is the correct sequence of spectral types of stars according to temperature? OBAFGKM
Synchrotron radiation is produced by high-velocity electrons moving through a magnetic field
A _____ is a city sized star supported by degenerate neutrons neutron star
When material expanding away from a star in a binary system reaches the Roche surface the material is no longer gravitationally bound to the star.
About how old is our sun? 5 billion years
If the Sun were replaced by a black hole having one solar mass, what would happen to the Earth's orbit? the Earth's orbit would remain the same
You can tell the age of a star cluster by using the HR diagram
the spectral type of a star measures its temperature
a star's luminosity depends only on the star's temperature and diameter
In relative terms, how does the Sun's temperature compare to all other stars? tends to be in the middle
The observed slowing of a clock in the vicinity of a black hole is a prediction of general relativity
an emission nebula is a region producing emission spectra
The total mass of a binary system can be calculated from the semi major axis and period of the orbit
What mechanism is most responsible for the twisting of the Sun's magnetic field lines? differential rotation
The centers of solar granules are hot material rising to the photosphere from below
The best way to observe cool Hydrogen atoms is 21 cm radiation
The heaviest element that stars can produce in their cores is Iron
What causes the outward pressure that balances the inward pull of gravity in a neutron star? the degenerate pressure of neutrons
How long does it take Sunlight to reach the Earth? 8 minutes
A star that has failed to gain enough mass to initiate fusion is a brown dwarf
What star is the most dense? a white dwarf
Reddening refers to scattering of blue light by dust
a planetary nebula is last gasp of a dying solar type star
What do Helioseiemologists study? the ringing Sun
In the twin paradox the faster twin lives longer
by what factor would the brightness of a star increase if an observer moved from 4 parsecs to 1 parsec from the star? 16
The two most abundant elements in the sun are hydrogen and helium
Of all the stars that are currently on the main sequence, which spectral type would be least abundant? B
What explanation does general relativity provide fro gravity? gravity is a result of curved space time
What is curious about jets? that they remain collimated over large distances
a neutron star is expected to spin rapidly because they conserved angular momentum when they collapsed
Sunspots appear dark because they are cooler regions
What nuclear fuels does a one solar mass star use over the course of its entire evolution? hydrogen and helium
The radio emission from radio galaxies and quasars is due to synchrotron radiation
What type of galaxy is the Andromeda galaxy M31? spiral
About how long does it take for the Sun to complete one trip around the galaxy? 250 million years
Quasars were originally discovered as strong radio sources identified with star-like images on photographs
When galaxies collide they simply perturb each others shape
The mass of a single galaxy might be found by the rotation curve method
Why is the energy source of active galaxies thought to be extremely compact? Their spectra are like those produced by ordinary stars.
Most of the mass of a galaxy is contained in the dark matter of the galaxy
What kind of galaxy do we live in? Spiral
How do we determine the masses of galaxies? Kepler's Law
The true distribution of galaxies is grouped in filaments, voids and clusters of galaxies
As matter streams in a black hole it usually forms what kind of structure? accretion disk
21 cm radiation is produced by which element? hydrogen
What was Klemperers dream about? colliding galaxies
The distribution of galaxies in the universe are arraigned on the surfaces of giant bubbles or voids
It is unlikely that astronauts will ever pass through black holes because tidal forces would rip them apart
About what percentage of the mass in the galaxy is "dark"? 90%
If our galaxy has a black hole at its center then why do we not see jets? It has consumed all available matter
Why are quasars called quasi-stellar? They look like stars on photographs
Most of the mass of a galaxy is contained in the dark matter of the galaxy
Which kinds of galaxies appear to have black holes at their centers? All
What good are 21 cm radio waves to galactic astronomers? Their Doppler shifts let us map the motions and locations of Hydrogen
Which type of galaxy contains the least amount of interstellar material? Ellipticals
What type of galaxy is frequently found at the center of a rich cluster of galaxies? elliptical
What is hardest to explain about spiral arm structure? how they maintain themselves
What is the name of the nearest large galaxy to our own? Andromeda
A rotation curve for a galaxy is a plot of orbital speed versus distance from center
What is the most likely source of energy for active galaxies and quasars? Accretion onto a super massive black hole
The location of our Sun in the galaxy is approximately about 2/3 of the way out to the edge
Why are the supermassive giant ellipticals found at the centers of the rich galaxy clusters? Such giants are the result of many mergers, cannibalizing smaller neighbors.
An Einstein ring and cross represent examples of distorted images
Hubble's law describes a relationship between a galaxy's redshift velocity and distance
For what type of object is the period-luminosity relation used for determining distances? Cepheids
Our galaxy has two smaller galaxies in orbit around it which are called Magellanic clouds
In what part of the spectrum can astronomers observe the 21 cm radiation? radio
What kind of galaxy has a rotation curve that does not fall off according to Kepler's laws out past the visible end? All
We can map out the distribution of dark matter by gravitational lensing
Created by: emulligan