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%\fancyfoot[LE,RO]{Ralf Kotulla}
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%% %\fancyhead[C]{Ralf Kotulla: Modeling explosive transient populations}
%% \fancyhead[L]{Scientific Data Processing \& Visualization in the cloud}
%% \fancyhead[R]{Ralf Kotulla: CIF21 DIBBs}














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\fancyhead[L]{Astronomy 103 - Midterm 3}
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\begin{document}
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\begin{center}
\large\bf Astronomy 103 --  Midterm 3 --  November 24, 2014
\end{center}


%\bigskip
%{\bf Solutions: correct answers are marked in bold, red type.}

\bigskip
{\bf Instructions:  } 

{\bf No books, notes or calculator are allowed.} You have 50 minutes to complete the exam, and please do not turn to the next page until instructed to do so.

%% {This exam consists of 50 questions. 45 correct questions correspond to a
%%   score of 100\%, i.e. 5 out of the 50 questions are bonus questions}

\bigskip
{\bf You may find the following information helpful:}

\begin{itemize}
\item{1 AU $=3\times10^8$ km}

\item{speed of light $c=3\times10^5$ km/s}

\item{Kepler's 3rd law: 
\[
a^3 = P^2 
\]
with the period $P$ in years and semi-major axis $a$ in AU.}

\item{Newton's law of gravity:
\[
F = \frac{GMm}{r^2}
\]}

\item{Peak wavelength and temperature of blackbody radiation:
\[
\lambda = \frac{3\times10^6}{T} \mbox{ nm}
\]
with wavelength $\lambda$ in nm (1 nm = $10^{-9}$ m) and temperature $T$ in
Kelvin.}

\item{Relationship between frequency $f$ and wavelength $\lambda$ of light:
\[
\lambda = \frac{c}{f}
\]}

\item{Conversion of mass into energy:  $E=mc^2$}

\item{Relationship between brightness $B$ and distance $d$:
\[
B_2 = B_1 \times \frac{d_1^2}{d_2^2}
\]}

\item{Relationship between luminosity $L$, temperature $T$ and radius $R$ of stars: 
\[
L=4\pi\sigma T^4 R^2
\]
where $4\pi \sigma$ are constants.}

\end{itemize}
\newpage


\begin{minipage}{0.55\textwidth}
\includegraphics[width=\textwidth]{1920px-Messier_81_HST.jpg}\\
Figure 1: Messier 81 (HST)
\end{minipage}

\vfill

\begin{minipage}{0.55\textwidth}
\includegraphics[width=\textwidth]{M101_hires_STScI-PRC2006-10a.jpg}\\
Figure 2: Messier 101 (HST)
\end{minipage}

\vfill

\begin{minipage}{0.70\textwidth}
\includegraphics[width=\textwidth]{GalaxyClusterAbell1689_sn.jpg}\\
Figure 3: Abell 1689 (Hubble)
\end{minipage}

\thispagestyle{empty}
%% \mbox{}
\newpage
\setcounter{page}{1}

%\begin{enumerate}[label=\arabic*.~, leftmargin=2em, itemsep=2ex]
\questions{1}










\item The density of a neutron star is closest to: 
\begin{enumerate}
\item 10 kg / teaspoon 
\item 1 atom / cubic centimeter 
\item 5 tons / teaspoon 
\correctitem{1 billion tons / teaspoon }
\end{enumerate}






\item A pulsar is a 
\begin{enumerate}
\item oscillating white dwarf 
\item oscillating neutron star 
\item rotating white dwarf 
\correctitem{rotating neutron star }
\item none of the above 
\end{enumerate}







%% \item Cygnus X-1 is almost certainly a black hol\item Which of these is an
%% important piece of evidence for this? a. Measurements of its mass and radius
%% show that it is much denser than a neutron star. \item Its measured mass is
%% larger than the maximum mass of a neutron star. \item It is the remnant of a
%% massive star which we observed exploding in a gamma ray burst. \item It is
%% observed to be perfectly black.

\item A black hole is likely to be the end of stellar evolution for what type of
main sequence star? 
\begin{enumerate}
  \correctitem{O }
\item M 
\item G 
\item A 
\end{enumerate}







\item What can escape from within a black hole? 
\begin{enumerate}
\correctitem{Neither light nor matter }
\item Light only 
\item Both light and matter 
\item Matter only
\end{enumerate}






\item The mass of a black hole candidate can be found by 
\begin{enumerate}
\item measuring its luminosity and distance 
\correctitem{measuring the speed of an orbiting companion and the radius of its orbit }
\item measuring the radius of its event horizon only 
\item measuring its luminosity and the radius of its event horizon 
\end{enumerate}







%% 7. The fastest-spinning neutron star known rotates about a. once a day
%% \item once an hour \item once a second \item 30 times a second \item 700 times a second



%% 8. Why do neutron stars in x-ray binaries rotate faster than most other
%% observed neutron stars? a. They are spun up by the gravitational tidal force
%% of their companion. \item They are spun up by matter that spirals onto them from
%% their companion star. \item Like other stars in binary systems, they spin faster
%% than isolated stars.

\enlargethispage{2ex}
\item Which of the following is not a terrestrial planet? 
\begin{enumerate}
\item Mars 
\item Earth 
\correctitem{Neptune }
\item Mercury 
\item Venus 
\end{enumerate}






\item Which of the following is not a Jovian planet? 
\begin{enumerate}
\correctitem{Venus }
\item Jupiter 
\item Neptune 
\item Saturn 
\item Uranus
\end{enumerate}






\item Compared to terrestrial planets, Jovian planets are 
\begin{enumerate}
\item larger and denser 
\item smaller and denser 
\correctitem{larger and less dense }
\item smaller and less dense 
\end{enumerate}






\item Most of the solar system's mass is in 
\begin{enumerate}
\correctitem{the Sun }
\item comets 
\item asteroids 
\item meteoroids 
\item planets 
\end{enumerate}






\item When a rotating cloud contracts, it 
\begin{enumerate}
\item spins slower and flattens 
\correctitem{spins faster and flattens }
\item spins slower and heats up 
\item spins faster and heats up 
\end{enumerate}






\item Why do all of the planets have orbits that lie in nearly the same plane
  and that are in the same direction -- counterclockwise looking down on the
  solar system from far above the Earth's North Pole? 

\begin{enumerate}
\item When they were captured by the Sun, the Sun was moving past a cluster of
planets, and all of those planets were on one side of its path. 
\item Shortly after they formed, the planets were moving in random directions. In
the 4 1/2 billion years since then, the Sun's gravity has pulled them into the
same plane. 
\correctitem{The planets and Sun all formed from a cloud of gas and dust that contracted as it cooled. As the cloud contracted, its spin increased and it flattened. By the time the planets formed, the cloud was a flat spinning disk.}
\end{enumerate}



%% \end{enumerate}


%% \newpage
%% For questions 12 to 15, choose one of the three following answers: 
%% \begin{enumerate}
%% \item comets 
%% \item meteoroids 
%% \item asteroids 
%% \end{enumerate}



%% \questions{12}
\newpage
\item Their orbits usually lie between Mars and Jupiter. 
\begin{enumerate}
\item comets 
\item meteoroids 
\correctitem{asteroids}
\end{enumerate}




\item They often pass the Sun once and then leave the solar system.
\begin{enumerate}
\correctitem{comets }
\item meteoroids 
\item asteroids 
\end{enumerate}




\item They have the lowest average density of the three kinds of objects. 
\begin{enumerate}
\correctitem{comets }
\item meteoroids 
\item asteroids 
\end{enumerate}





\item  They are typically small pebbles. 
\begin{enumerate}
\item comets 
\correctitem{meteoroids }
\item asteroids 
\end{enumerate}









\item  What is the reason for the difference between typical meteors and typical
meteorites? 
\begin{enumerate}
\correctitem{The only meteors that do not burn up in the atmosphere are the large
ones. These are all asteroid fragments. }
\item The only meteors that do not burn up in the atmosphere are the rocky
ones. These all come from comets. 
\item Meteorites are the meteors that burn up in the atmosphere. 
\item Meteors are ice balls, while meteorites are great balls of fire.
\end{enumerate}







\item Comet tails extend from the comet in what direction? 
\begin{enumerate}
\correctitem{away from the Sun }
\item away from the Sun when the comet is approaching the Sun and toward the Sun
when the comet is moving away 
\item toward the Sun
\end{enumerate}


%% \end{enumerate}



%% \bigbreak
%% For questions 18 to 21, choose one of the following answers: 
%% \begin{enumerate}
%% \item Jupiter 
%% \item Mercury 
%% \item Mars 
%% \item Venus 
%% \item Uranus 
%% \end{enumerate}


%% \questions{18}

\newpage
\item The greenhouse effect makes this the planet with the hottest average
temperature in the solar system. 
\begin{enumerate}
\item Jupiter 
\item Mercury 
\item Mars 
\correctitem{Venus }
\item Uranus 
\end{enumerate}




\item This planet is about 20 AU from the Sun. 
\begin{enumerate}
\item Jupiter 
\item Mercury 
\item Mars 
\item Venus 
\correctitem{Uranus }
\end{enumerate}




\item This planet is the only one of those listed that was not known to the
ancient Greeks. 
\begin{enumerate}
\item Jupiter 
\item Mercury 
\item Mars 
\item Venus 
\correctitem{Uranus }
\end{enumerate}




\item This planet has no liquid water on its surface, but does have channels which
are probably the streambeds of ancient rivers. 
\begin{enumerate}
\item Jupiter 
\item Mercury 
\correctitem{Mars }
\item Venus 
\item Uranus 
\end{enumerate}





\item  The average density of the Earth is about 
\begin{enumerate}
\item the density of water 
\item the density of iron 
\correctitem{the density of black volcanic rock }
\item the density of ice 
\end{enumerate}





\newpage
\item  The Earth's atmosphere is primarily 
\begin{enumerate}
\item carbon dioxide and oxygen 
\item water vapor and carbon dioxide 
\correctitem{nitrogen and oxygen }
\item methane and ammonia 
\item nitrogen and water vapor 
\end{enumerate}







\item Mars is larger than the Earth. 
\begin{enumerate}
\item TRUE 
\correctitem{FALSE}
\end{enumerate}






\item What are the main constituents of Mars? 
\begin{enumerate}
\item hydrogen and rock 
\item rock and ice 
\item water, methane and ammonia 
\item hydrogen and helium 
\correctitem{rock and iron }
\end{enumerate}






%% For questions 29 to 31, choose one of the following answers: 
%% \begin{enumerate}
%% \item Mars 
%% \item Mercury 
%% \item Earth 
%% \item Venus 
%% \item Jupiter
%% \end{enumerate}







\item The crater-covered surface of this terrestrial planet resembles the
  surface of the Moon. 
\begin{enumerate}
\item Mars 
\correctitem{Mercury }
\item Earth 
\item Venus 
\item Jupiter
\end{enumerate}





\item Olympus Mons is a volcano on this planet. 
\begin{enumerate}
\correctitem{Mars }
\item Mercury 
\item Earth 
\item Venus 
\item Jupiter
\end{enumerate}





\item Jupiter emits more energy than it receives from the Sun. 
\begin{enumerate}
\correctitem{TRUE }
\item FALSE
\end{enumerate}








\item Dry ice (frozen carbon dioxide) vastly enlarges this planet's polar caps
  in the winter for each cap. 
\begin{enumerate}
\correctitem{Mars }
\item Mercury 
\item Earth 
\item Venus 
\item Jupiter
\end{enumerate}





\item Voyager discovered active volcanoes on what moon? 
\begin{enumerate}
\item Phobos 
\item Ganymede 
\item Titan 
\item Europa 
\correctitem{Io }
\end{enumerate}







\item The Great Red Spot is 
\begin{enumerate}
\item a desert on Mars 
\item a crater on the moon 
\correctitem{a persistent storm on Jupiter }
\end{enumerate}






\item Pluto is now classified as 
\begin{enumerate}
\item a cold terrestrial planet 
\correctitem{a large Kuiper belt object }
\item a comet in a bound orbit 
\end{enumerate}







\item Pluto is the largest of the known plutoids. 
\begin{enumerate}
\item TRUE 
\correctitem{FALSE}
\end{enumerate}







\item Plutoids are 
\begin{enumerate}
\item comets in the Oort cloud 
\correctitem{balls of ice and rock in the Kuiper belt }
\item carbonaceous chondrites between Mars and Jupiter 
\item the moons of the Jovian planets that are primarily ices of water, ammonia,
carbon dioxide, and methane 
\end{enumerate}







\newpage\item Compared to Population I stars, Population II stars are 
\begin{enumerate}
\correctitem{older, with a smaller fraction of heavy elements }
\item younger, with a larger fraction of heavy elements 
\item older, with a larger fraction of heavy elements 
\item younger, with a smaller fraction of heavy elements 
\end{enumerate}







\item What population of stars are found in globular clusters? 
\begin{enumerate}
\item Population I only 
\correctitem{Population II only }
\item both Population I and Population II 
\item neither
\end{enumerate}





%\enlargethispage{2ex}
\item Each method of finding distances (or distance indicator) listed below is
  used to find the distance to a set of objects. Match the indicators to the
  objects. 

\begin{enumerate}[label=\arabic*]
\item radar bouncing 
\item parallax 
\item main-sequence matching ("spectroscopic parallax") 
\item Cepheid variables 
\end{enumerate}

\begin{enumerate}[label=\Alph*]
\item distances to planets 
\item distances to the nearest stars 
\item distances to nearby galaxies 
\item distances to stars in the Milky Way more than 2,000 ly away
\end{enumerate}

\begin{enumerate}
\item A and 2, B and 3, C and 1, D and 4 
\item A and 3, B and 1, C and 4, D and 2
\correctitem{A and 1, B and 2, C and 4, D and 3  }
\item A and 4, B and 3, C and 1, D and 2
\end{enumerate}






\item The Milky Way is 
\begin{enumerate}
\correctitem{a spiral galaxy }
\item an elliptical galaxy 
\item a globular cluster 
\item an irregular galaxy 
\end{enumerate}






%\enlargethispage{4ex}
\newpage
\item In which part of the Milky Way galaxy is the Sun? 
\begin{enumerate}
\item halo 
\correctitem{disk }
\item central bulge 
\item none of these 
\end{enumerate}







\item Most of the mass of the Milky Way galaxy is 
\begin{enumerate}
\item in the spiral arms 
\item in the disk, but not in the spiral arms 
\item in the nuclear bulge 
\correctitem{invisible and in the halo }
\item in the brightest, most massive stars of halo
\end{enumerate}







\item The strongest evidence for a black hole in the center of the Milky Way is 
\begin{enumerate}
\correctitem{Observed orbits of stars show nearly 4 million times the mass of the Sun is
in a region less than 6 light-hours across. }
\item Doppler shifts of 21-cm radiation from the galactic center imply that roughly
50 million times the mass of the Sun lies within a region 3 light-years across, 
\item Observed orbits of stars show nearly 30 million times the mass of the Sun is
in a region less than 8 light-seconds across. 
\item Doppler shifts of 21-cm radiation from the galactic center imply that over
one billion times the mass of the Sun lies within a region 3 light-years
across. 
\item None of these is thought to be evidence for a central black hole. 
\end{enumerate}






\item What is the approximate diameter of the disk of the Milky Way? 
\begin{enumerate}
\correctitem{100,000 ly }
\item 300,000 ly 
\item 3 million ly 
\item 100 million ly
\end{enumerate}






%\newpage
\item Why is 21 cm radio emission useful for studying the structure of the Milky Way
\begin{enumerate}
\item The waves penetrate dusty cocoons to reveal star formation
\item The waves are not absorbed by Galactic black holes
\correctitem{It can be used to map the hydrogen gas in the spiral arms}
\item Radio waves provide a distance measurement like parallax
\end{enumerate}






\newpage
\item What convincing evidence do we have for the presence of a relatively dense
  halo of invisible ``dark matter'' permeating the Milky Way?
\begin{enumerate}
\item Light from distant stars is blocked by some unseen effect
\item Much of the matter making up the Milky Way is far colder than it should be
\item Many of the stars in the Milky Way are losing energy, as though passing through
a dense cloud of material
\correctitem{Stars further out in the galactic disk seem to be moving at about the same speed
as those that are further in, when they should be moving slower.}
\end{enumerate}







\item What is the rough proportion (by total mass) in the universe of
  well-understood visible matter to poorly understood ``dark'' matter?
\begin{enumerate}
\item The amount of dark matter is about one percent the amount of visible matter
\item The amount of dark matter is about one fifth the amount of visible matter
\item The amount of dark matter is about equal to the amount of visible matter
\correctitem{The amount of dark matter is about five times the amount of visible matter}
\item The amount of dark matter is about one hundred times  the amount of visible matter
\end{enumerate}







\item How are galaxies spread out throughout the universe
\begin{enumerate}
\item They are grouped into clusters that are spread more-or-less evenly throughout space
\correctitem{They are grouped into clusters that in turn are clumped into superclusters}
\item Galaxies are densest near us, and become more spread out as we look further out
\item Galaxies are densest near a distant point in space, which can be interpreted as
the center of the universe, and are ore spread out as one looks way from that
point.
\end{enumerate}






\item What is Hubble's Law based on
\begin{enumerate}
\item More distant galaxies showing greater blueshifts
\item Distant galaxies appearing proportionally dimmer
\correctitem{More distant galaxies showing greater redshifts}
\item Slowly varying Cepheid variables appearing brighter
\end{enumerate}


%\newpage
\item What is the Hubble classification for the galaxy shown in Figure 1 (see
  page between Instructions and Questions)?
\begin{enumerate}
\item E
\correctitem{Sa}
\item Sc
\item Irregular
\item Quasar
\end{enumerate}

\newpage
\item What is the Hubble classification for the galaxy shown in Figure 2?
\begin{enumerate}
\item E
\item Sa
\correctitem{Sc}
\item Irregular
\item Quasar
\end{enumerate}


\item Most of the galaxies shown in Figure 3 have what Hubble classification?
\begin{enumerate}
\correctitem{E}
\item Sa
\item Sc
\item Irregular
\item Quasar
\end{enumerate}

\end{enumerate}

\vfill

\centerline{\huge Happy Thanksgiving!}
\vfill
\mbox{}

\newpage





\label{lastpage}

\end{document}
