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How many high tides are there in a day on average? |
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Why do we see both total and annular solar eclipses? |
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the moon's orbit around earth is not exactly circular |
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of these stars, which is coolest: red, yellow, green, dark red |
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When we think of epicycles, we think of: |
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What would you use to image very cold clouds containing atomic hydrogen? |
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What is the most important parameter that determines the behavior of star? |
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Which planet is least dense? |
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Which planet has the largest magnetic field? |
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What objects can be binary? |
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Definition
main sequence stars, black holes, neutron stars, red giants, and white dwarfs |
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Increasing the diameter of a telescope primary lens: |
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Definition
makes light gathering power go up |
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that any object at any temperature above absolute zero will emit a characteristic distribution of wave lengths of light |
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What balances the sun's huge gravitational force, keeping it from collapsing? |
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What is the last and heaviest element that can be created from fusion in the normal evolution of a high-mass star? |
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As our Sun leaves the main sequence: |
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Definition
It will have a helium flash and move into the horizontal branch of the H-R diagram |
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If you were to see signals coming into your radio telescope receiver, you'd think you were seeing |
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signals from a rapidly spinning neutron star |
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An old star cluster in the Halo of the milky way is generally a |
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A new, star-like object appears to have magnitude -10 M. It could be: |
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a supernova in the Milky Way or some distant galaxy |
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Elusive particles created by the sun that allow astronomers to determine what nuclear fusion reaction powers it |
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How massive can a black hole be? |
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Definition
Any size, as long as all the mass is within the Schwarzschild radius for that mass value |
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Noting the turnoff mass in a star cluster on an H-R diagram allows you to determine its |
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What kind of stars are used as "standard candles" to estimate the distances to star clusters in the Milky Way? |
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Cepheid and RR Lryae Variables |
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the location of a super massive black hole at the center of the Milky Way |
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What represents the Local Group? |
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Definition
Andromeda, Sagittarius drawf, large and small magellanic clouds, milky way, and other neighbors |
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Term
What is a proposed explanation for gamma ray bursters? |
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Definition
a hypernova making black holes and bi-polar jets |
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Term
*What are typical values of luminosity in AGNs? |
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Definition
Greater than 10^37 W, which means they consumer on average on sun's mass every couple of years. |
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*What is special about the emission spectra coming from AGNs? |
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Definition
they have non-stellar emissions |
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*what is special about the energy output of an AGN? |
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Definition
it is highly variable, indicating that the emission source is very compact (> a parsec in size) |
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Definition
usually have jets and accretion disks, with a black hole at the center |
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*What to AGN emission lines look like? |
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Definition
Very broad, indicating that their source is undergoing rapid internal motion (in more than one direction) |
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Term
What do data points near region A refer to? |
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Definition
older galaxies near to to us |
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Term
What do data points near region C refer to? |
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Definition
younger galaxies that are far from us |
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Term
Fact that the data falls below the straight lines near region C means that |
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Definition
the early universe was expanding more slowly than it is now |
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Term
What is the shape of an open universe? |
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Definition
the potato chip/saddle shape |
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Term
If two laser pointers sent out two parallel beams into space, they would ultimately cross at |
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Definition
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Term
The universe is similar in both ways from us, 14 billion years each way. Why is this? They could not have communicated because it would have taken 28 billion years and that is older than the universe itself. |
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Definition
Inflation theory can explain it |
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Term
What makes up critical density? |
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Definition
visible matter, dark matter, dark energy |
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Term
What information does the cosmic background radiation give us? |
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Definition
a picture of the sizes of early dark matter-shrouded galaxies, and a measure of the temperature of the present universe (2.7 K) |
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Term
How far does light travel in 32.6 years? |
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Definition
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tripling the diameter of a telescope with angular resolution of 1 arcsecond makes the angular resolution: |
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Definition
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Term
Find mass of a black hole given we see a star orbit it once a year, at a distance of 10 AU (keppler's law: M=A^3/P^2 |
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Definition
1000 thousand solar masses |
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Term
a star has a parallax of .001 arcseconds. how far away is it? |
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Definition
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two same size stars, one is 4x hotter. How much more luminous is it? |
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Definition
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How long is a year on Pluto? (40 AU from sun) |
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a star blows up, releasing 1.8x10^47 J of energy. It is what kind of star? |
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Definition
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Term
In the milky way, the sun is located: |
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Definition
about 8kpc from the center |
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Term
stars in the outermost regions of the milky way |
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Definition
orbit faster than expected based on the galactic mass we can see |
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Term
Most of the mass of the milky way exists in the form of |
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Definition
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Term
Hubble's law implies that |
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Definition
the greater the distance to a galaxy, faster it is moving away from us |
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Term
If the light from a galaxy fluctuates in brightness very rapidly, the region producing the radiation must be |
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Definition
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charged particles spiraling around magnetic field lines can produce |
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Definition
Inferring the distance to the galaxy through a measurement of its rotation rate |
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Galaxies that look like normal spiral galaxies, but have extremely bright galactic nuclei |
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More than ___% of the mass in the universe is dark |
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Definition
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A close encounter or collision between two galaxies may result in |
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Definition
a burst of star formation |
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Term
inflation theory solves the cosmological |
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galactic distances used to measure acceleration of universe are determined by observations of |
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chemical elements that form the basic molecules needed for life are found |
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Definition
commonly through the cosmos |
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Term
the centers of quasar are typically |
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Definition
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gravitational lensing causes |
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Definition
the light from distant stars to be bent or focused by unseen massive objects in its path |
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Definition
periodic blips in the received radio signals usually occuring at short intervals |
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Term
takes 8.3 minutes for light to reach earth. new object is found, 100 AU from sun. how long does it take light to reach this object? |
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Definition
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Term
How long does it take the moon to orbit on its axis? |
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Definition
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how long does it take the sun to rotate once on its axis? |
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Definition
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most important parameter that determines a star's evolution? |
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Definition
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Term
astronomers generally believe that planetary magnetic fields originate from: |
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Definition
the dynamo effect and liquid, metallic cores |
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Term
millisecond pulsars are mostly observed in |
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Definition
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biggest magnetic fields in the universe are probably associated with: |
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Definition
neutron stars and magnetars |
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Term
if you observe 4 identical images of the same quasar, |
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Definition
there is probably a dark matter between you at the quasar |
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Term
If you observe an object orbiting another object, you can determine: |
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Definition
the total mass of the binary system |
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Term
what constellation was rising in the east at the beginning of the semester, and is now setting in the west at the end of the semester? |
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Definition
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Term
if the moon's orbit were a little larger, solar eclipses would be |
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Definition
more likely to be annular |
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Term
Light coming from star has wavelength of 1000 nm. How hot is it? |
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Definition
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Term
Wavelength in nanometers of light coming from very hot star (about 29,000 K) |
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Definition
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Comet orbits the sun once every 10 years. What is the average distance from the sun to the comet? |
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Definition
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Temperature of star is 59,000 K. How much more power does it emit than the sun? (Sun is 5900 K) |
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Definition
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Term
why doesn't Venus have a magnetic field? |
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Definition
its extremely slow rotation doesn't produce a significant dynamo effect. |
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Term
Sun's average density is almost exactly the same as: |
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Definition
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Term
Star has parallax of .05 arcseconds, its distance is |
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Definition
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Term
in the proton-proton cycle, lost mass is: |
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Definition
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Term
when multiple radio telescopes are used for interferometry, resolving power (angular resolution) is most improved by increasing: |
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Definition
distance between telescopes |
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Term
emission nebulae like M-42 occur only near stars that emit large amounts of |
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Definition
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Term
on a H-R diagram, a protostar would be |
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Definition
above and to the right of the main sequence |
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Term
characteristics of globular clusters |
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Definition
old age, hundred of thousands of stars, only about 30 ly wide |
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Term
a recurrent nova could eventually build up to: |
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Definition
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Definition
leading candidate for an observable black hole binary system |
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Term
Mass range for a neutron star |
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Definition
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Term
Logical sequence of galaxy evolution: |
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Definition
quasar, active galaxy, and normal galaxy |
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Term
Obler's paradox is resolved by |
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Definition
the finite age of the universe |
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Term
horizon problem in standard big bang model is solved by having the universe: |
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Definition
inflate rapidly early in its existence |
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